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  • Nitrogen
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  • 1
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    Linking variation in planktonic primary production to coral reef fish growth and condition (2023)
    The Royal Society
    Details
    Publication Date: 2023-03-02
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Roche, R. C., Heenan, A., Taylor, B. M., Schwarz, J. N., Fox, M. D., Southworth, L. K., Williams, G. J., & Turner, J. R. Linking variation in planktonic primary production to coral reef fish growth and condition. Royal Society Open Science, 9(8), (2022): 201012, https://doi.org/10.1098/rsos.201012.
    Description: Within low-nutrient tropical oceans, islands and atolls with higher primary production support higher fish biomass and reef organism abundance. External energy subsidies can be delivered onto reefs via a range of physical mechanisms. However, the influence of spatial variation in primary production on reef fish growth and condition is largely unknown. It is not yet clear how energy subsidies interact with reef depth and slope. Here we test the hypothesis that with increased proximity to deep-water oceanic nutrient sources, or at sites with shallower reef slopes, parameters of fish growth and condition will be higher. Contrary to expectations, we found no association between fish growth rate and sites with higher mean chlorophyll-a values. There were no differences in fish δ15N or δ13C values between depths. The relationship between fish condition and primary production was influenced by depth, driven by increased fish condition at shallow depths within a primary production ‘hotspot’ site. Carbon δ13C was depleted with increasing primary production, and interacted with reef slope. Our results indicate that variable primary production did not influence growth rates in planktivorous Chromis fieldi within 10–17.5 m depth, but show site-specific variation in reef physical characteristics influencing fish carbon isotopic composition.
    Description: Fieldwork was supported by the Fondation Bertarelli.
    Keywords: Nitrogen ; Coral reef fish ; Pelagic energetic subsidies ; Stable isotope analysis ; Primary production ; Carbon
    Repository Name: Woods Hole Open Access Server
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  • 2
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    Assessment of the hydrochemical status of the Azov Sea based on the data collected during field surveys in 2019–2020 (2022)
    Details
    Publication Date: 2022-03-01
    Description: This work presents the results of the investigation of the influence the biogenic substances exercise on the primary production of organic matter by phytoplankton in the Azov Sea in 2019–2020. The analysis of the oxygen regime and the development of kill events has been conducted. During the investigated period, the changes in the oxygen regime of the Azov Sea were observed over the course of time. The content of ammonium nitrogen and phosphorus, as well as nitrate and total ones, in the Azov Sea influences the level of organic matter primary production by phytoplankton to a considerable degree. At present, as the result of low river flow volume, the concentration of biogenic substances is decreasing, which, in turn, leads to the decrease in the primary production of organic matter. The equations describing the relationship between the primary production and the content of biogenic substances are considered.
    Description: В работе представлены результаты исследования влияния содержания биогенных веществ на первичное продуцирование органического вещества фитопланктоном в Азовском море в 2019–2020 гг. Проведен анализ кислородного режима и особенностей формирования заморов. В исследуемый период прослежена динамика изменения кислородного режима Азовского моря. Концентрации аммонийного, нитратного, а также общего азота и фосфора в Азовском море оказывают существенное влияние на уровень первичного продуцирования органического вещества фитопланктоном. В современный период в связи с низким объемом речного стока снижается концентрация биогенных веществ, что приводит к снижению первичного продуцирования органического вещества. Рассмотрены уравнения зависимости первичной продукции от концентрации биогенных элементов.
    Description: Published
    Description: Non Refereed
    Keywords: Oxygen regime ; River runoff ; Nitrogen ; Primary production ; Кислородный режим ; Речной сток ; Азот ; Нитраты ; Nitrаtes ; ASFA_2015::B::Biogenic material ; ASFA_2015::O::Organic matter ; ASFA_2015::P::Phytoplankton
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: pp.82-89
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  • 3
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    A compilation of dissolved noble gas and N2/Ar ratio measurements collected from 1999-2016 in locations spanning the globe (2022)
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Details
    Publication Date: 2022-10-31
    Description: Dataset: Global Noble Gases
    Description: Inert gases dissolved in the ocean are powerful tracers of the impact of physical processes on gases, particularly air-sea gas exchange (by both diffusive and bubble-meditated processes), temperature change, atmospheric pressure variation, mixing between different water masses, and ice processes. We have compiled a global ocean database of dissolved neon, argon, and krypton measurements, supplemented by helium, xenon, and nitrogen/argon (N2/Ar) ratios in some locations. Samples were collected on board multiple research cruises spanning the period 1999 through 2016 and analyzed by mass spectrometry at four different shore-based laboratories (University of Victoria, Woods Hole Oceanographic Institution, University of Washington, and Scripps Institution of Oceanography). Version 2.0 corrects an incorrect sign in the longitude for cruise 33KI20040814:HOT162 in version 1.0. The error in the database does not affect any figures in the publication (doi: 10.1146/annurev-marine-121916-063604). For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/743867
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-0623034, NSF Division of Ocean Sciences (NSF OCE) OCE-0926659, National Sciences and Engineering Research Council of Canada (NSERC) 328290-2006, NSF Division of Ocean Sciences (NSF OCE) OCE-1130870, NSF Division of Ocean Sciences (NSF OCE) OCE-1232991, NSF Division of Ocean Sciences (NSF OCE) OCE-1029299, National Sciences and Engineering Research Council of Canada (NSERC) 329290-2012, National Sciences and Engineering Research Council of Canada (NSERC) 433848-2012, National Sciences and Engineering Research Council of Canada (NSERC) 433898-2012, NSF Division of Ocean Sciences (NSF OCE) OCE-9617487, NSF Division of Ocean Sciences (NSF OCE) OCE-9819181, NSF Division of Ocean Sciences (NSF OCE) OCE-9906922, NSF Division of Ocean Sciences (NSF OCE) OCE-0221247, NSF Division of Ocean Sciences (NSF OCE) OCE-0242139, NSF Division of Ocean Sciences (NSF OCE) OCE-0647979, NSF Division of Ocean Sciences (NSF OCE) OCE-0825394
    Keywords: Noble gases ; Nitrogen ; Neon ; Argon ; Krypton ; Carbon pumps
    Repository Name: Woods Hole Open Access Server
    Type: Dataset
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  • 4
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    Isotopic signals in an agricultural watershed suggest denitrification is locally intensive in riparian areas but extensive in upland soils (2022)
    Springer
    Details
    Publication Date: 2022-06-10
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Sigler, W. A., Ewing, S. A., Wankel, S. D., Jones, C. A., Leuthold, S., Brookshire, E. N. J., & Payn, R. A. Isotopic signals in an agricultural watershed suggest denitrification is locally intensive in riparian areas but extensive in upland soils. Biogeochemistry, 158, (2022): 251–268, https://doi.org/10.1007/s10533-022-00898-9.
    Description: Nitrogen loss from cultivated soils threatens the economic and environmental sustainability of agriculture. Nitrate (NO3−) derived from nitrification of nitrogen fertilizer and ammonified soil organic nitrogen may be lost from soils via denitrification, producing dinitrogen gas (N2) or the greenhouse gas nitrous oxide (N2O). Nitrate that accumulates in soils is also subject to leaching loss, which can degrade water quality and make NO3− available for downstream denitrification. Here we use patterns in the isotopic composition of NO3− observed from 2012 to 2017 to characterize N loss to denitrification within soils, groundwater, and stream riparian corridors of a non-irrigated agroecosystem in the northern Great Plains (Judith River Watershed, Montana, USA). We find evidence for denitrification across these domains, expressed as a positive linear relationship between δ15N and δ18O values of NO3−, as well as increasing δ15N values with decreasing NO3− concentration. In soils, isotopic evidence of denitrification was present during fallow periods (no crop growing), despite net accumulation of NO3− from the nitrification of ammonified soil organic nitrogen. We combine previous results for soil NO3− mass balance with δ15N mass balance to estimate denitrification rates in soil relative to groundwater and streams. Substantial denitrification from soils during fallow periods may be masked by nitrification of ammonified soil organic nitrogen, representing a hidden loss of soil organic nitrogen and an under-quantified flux of N to the atmosphere. Globally, cultivated land spends ca. 50% of time in a fallow condition; denitrification in fallow soils may be an overlooked but globally significant source of agricultural N2O emissions, which must be reduced along-side other emissions to meet Paris Agreement goals for slowing global temperature increase.
    Description: National Institute of Food and Agriculture, 2011–51130-31121, S. A. Ewing, 2011, S. A. Ewing, 2016–67026-25067, S. A. Ewing, Montana State University Extension, Montana Fertilizer Advisory Committee, Montana Agricultural Experiment Station, Montana State University Vice President of Research, Montana State University College of Agriculture, Montana Institute on Ecosystems, NSF EPSCoR, OIA-1757351, S. A. Ewing, OIA-1443108, S. A. Ewing, EPS-110134, S. A. Ewing.
    Keywords: Nitrogen ; Agriculture ; Soil ; Water ; Leaching ; Fallow
    Repository Name: Woods Hole Open Access Server
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  • 5
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    Ammonium and sulfate assimilation is widespread in benthic foraminifera (2022)
    Frontiers Media
    Details
    Publication Date: 2022-11-15
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in LeKieffre, C., Jauffrais, T., Bernhard, J., Filipsson, H., Schmidt, C., Roberge, H., Maire, O., Panieri, G., Geslin, E., & Meibom, A. Ammonium and sulfate assimilation is widespread in benthic foraminifera. Frontiers in Marine Science, 9, (2022): 861945, https://doi.org/10.3389/fmars.2022.861945.
    Description: Nitrogen and sulfur are key elements in the biogeochemical cycles of marine ecosystems to which benthic foraminifera contribute significantly. Yet, cell-specific assimilation of ammonium, nitrate and sulfate by these protists is poorly characterized and understood across their wide range of species-specific trophic strategies. For example, detailed knowledge about ammonium and sulfate assimilation pathways is lacking and although some benthic foraminifera are known to maintain intracellular pools of nitrate and/or to denitrify, the potential use of nitrate-derived nitrogen for anabolic processes has not been systematically studied. In the present study, NanoSIMS isotopic imaging correlated with transmission electron microscopy was used to trace the incorporation of isotopically labeled inorganic nitrogen (ammonium or nitrate) and sulfate into the biomass of twelve benthic foraminiferal species from different marine environments. On timescales of twenty hours, no detectable 15N-enrichments from nitrate assimilation were observed in species known to perform denitrification, indicating that, while denitrifying foraminifera store intra-cellular nitrate, they do not use nitrate-derived nitrogen to build their biomass. Assimilation of both ammonium and sulfate, with corresponding 15N and 34S-enrichments, were observed in all species investigated (with some individual exceptions for sulfate). Assimilation of ammonium and sulfate thus can be considered widespread among benthic foraminifera. These metabolic capacities may help to underpin the ability of benthic foraminifera to colonize highly diverse marine habitats.
    Description: This work was supported by the Swiss National Science Foundation (grant no. 200021_149333), and a postdoctoral fellowship allowed to CL by the University Loire-Bretagne. SBB sampling was funded by US National Science Foundation grant BIO IOS 1557430 to JMB, who also acknowledges NASA grant #80NSSC21K0478 for partial support. HF acknowledges funding from the Swedish Research Council VR (grant number 2017-04190). Svalbard sampling was supported by the Research Council of Norway through CAGE (Center for Excellence in Arctic Gas Hydrate Environment and Climate, project number 223259) and NORCRUST (project number 255150) to GP and the fellowship MOPGA (Make Our Planet Great Again) by CAMPUS France to CS.
    Keywords: Marine protists ; Coastal environments ; Biogeochemical cycles ; NanoSIMS ; Nitrogen ; Sulfur
    Repository Name: Woods Hole Open Access Server
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  • 6
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    The fate of anthropogenic nitrogen in a redox stratified pond: an isotopic approach (2022)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2023-01-18
    Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Chemical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2022.
    Description: The environmental effects of both increased urbanization and eutrophication are of growing global concern. Coastal areas, like those found on Cape Cod, Massachusetts, often experience severe impacts associated with the biogeochemical effects accompanying increased nitrogen pollution. Cape Cod is home to roughly 1,000 ponds and lakes which play an important role in local ecosystems, but the cycling of nitrogen in these waters is not well understood. The goal of this research is to identify the major biogeochemical cycling processes responsible for the fate of nitrogen in a nitrogen-rich, coastal, stratified pond. The investigation was carried out through regular high-resolution measurement and monitoring of environmental conditions, nitrogen speciation, and isotopic composition over the course of a summer. Elevated nitrogen concentrations coupled with strong redox gradients make Siders Pond an ideal place for studying dynamics of nitrogen transformations, giving insight into nitrogen retention or removal, which influence water quality. These data demonstrate significant dissolved nitrogen loss from the pond over the course of the summer as well as internal nitrogen cycling that promotes dissolved nitrogen accumulation to extreme levels in the deepest depths. The physical dynamics of mixing promote a coupling of nitrification and denitrification across this redox gradient, driving N loss while also supplying the sunlit waters with nutrient-rich deep water. A simple time-resolved box model suggests that approximately 50% of the upwardly delivered N is removed, while the other portion supports recycling through photosynthetic uptake. While dissolved organic nitrogen (DON) is widely considered refractory material and is rarely measured or reported in environmental studies, here there is evidence for a large and dynamic pool of DON within Siders Pond suggesting important dynamics between organic and inorganic pools in regulating N loss. While nitrate is a commonly used measurement for assessing N contamination, this work highlights the parallel importance of monitoring additional species (including ammonium and DON) for determining eutrophication/contamination. A deeper understanding of Siders Pond can be used to elucidate nitrogen cycling dynamics in analogous redox-stratified systems, including other lakes and ponds, or modern ocean regions such as the Santa Barbara and Cariaco Basins and the Baltic and Black Seas.
    Description: National Science Foundation (project number NSF-1924236)
    Keywords: Nitrogen ; Stable isotopes ; Lakes and ponds
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
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  • 7
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    Nitrogen and phosphorus forms in water and the food requirements of algae. [Translation from: Wiadomosci Ekologiczne 19 238-244, 1973. ] (2021)
    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4848 | 1256 | 2011-09-29 15:49:18 | 4848 | Freshwater Biological Association
    Details
    Publication Date: 2021-07-06
    Description: When dissolved in water, compounds of nitrogen and phosphorus ought to contain the basic assimilated food requirements for autotrophic plants and therefore autotrophic algae. This article summarises the occurrence of nitrogen in water, how species of algae utilize nitrogen and phosphorus forms for growth and the capacities of algae to adapt to environments of different nutrient wealth. This topic has unquestionable importance not only for the purpose of survival of a species but also in deciding indirectly about the stability of ecosystems.
    Description: Translated from Polish into English
    Keywords: Biology ; Chemistry ; Limnology ; Algae ; Nitrogen fixation ; Nitrogen ; Phosphorus ; Nutritional requirements ; Bacteria ; Organic compounds
    Repository Name: AquaDocs
    Type: monograph
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  • 8
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    The effect of oxygen concentration in water on the growth and nitrogen metabolism in the fry of rainbow trout [Translation from: Rybnoe Khoziaistvo,V.33, 74-75, 1957] (2021)
    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/5029 | 1256 | 2011-09-29 15:32:00 | 5029 | Freshwater Biological Association
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    Publication Date: 2021-07-08
    Description: To ascertain the effect of various concentrations of oxygen in water on the fry of rainbow trout experiments were made with aquaria at various concentrations of oxygen. The food supplied was chironomid larvae (Chironomus plumosus). A surplus of food was supplied to the fry. Indices are given of the reaction of the fry to different temperatures.
    Description: Translated from Russian into English
    Keywords: Biology ; Limnology ; Oxygen consumption ; Metabolism ; Nitrogen ; Freshwater fish ; Animal growth ; Fry ; Oncorhynchus mykiss
    Repository Name: AquaDocs
    Type: monograph
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  • 9
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    Ecological study on the Persian Gulf Martyres Lake, Tehran (2021)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25818 | 18721 | 2018-10-13 10:23:49 | 25818 | Iranian Fisheries Science Research Institute
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    Publication Date: 2021-07-16
    Description: The ecological study of the Persian Gulf Martyres Lake carried out at the 5 stations between 2013 and 2014. This study identified 35 phytoplankton taxa. The diatoms taxa was dominated and their abundance recorded highest (2000 000 cell. L^-1) in the lake. The annual phytoplankton abundance was measured as 2500 000 cell. L^-1 during the study. The total nitrogen and water temperature were the significant a biotic parameters to increase cyanophytes abundance. Furthermore, 37 zooplankton taxa were identified. The Rotatoria abundance was dominated zooplankton. The annual zooplankton abundance was measured as 72 ind.l-1. Based on the CCA, there was no correlation between Rotatoria abundance and a biotic parameters. The study benthos showed Ephemeroptera and Diptera abundance were dominated; artificial bottom and lack of sediment and organic matters were the main reasons in decreasing of the benthos density. The Chitgar lake is the poorest lake in Iran due to low density of plankton and benthos organisms. The estimation of fish production was 123 kg/ha and for the lake was determaind 16 tonne. The finding display, invasive species was the main fish Chitgar lake that would be negative effect and increase eutriphication trend in the lake. Phosphorus parameter was limited parameters and trophy level recorded low due to high N/P ration in the lake. In overall the Chitgar lake situation is in Oligotrophic category with the low trophy level.
    Keywords: Ecology ; Iran ; Persian Gulf ; Chitgar Lake ; Phytoplankton ; Zooplankton ; Benthose ; Trophy ; Abundance ; Nitrogen ; Temperature
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
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  • 10
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    The effects of slurry on larviculture of Rutilus frisii kutum and chienes carp yield and determination of efficient concentration for increasing of production (2021)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25300 | 18721 | 2018-09-08 16:40:33 | 25300 | Iranian Fisheries Science Research Institute
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    Publication Date: 2021-07-16
    Description: Rutilus frisii kutum is one of the important fish of Caspian Sea which has significant economical role in the region .The objective of this project is a comparative study on traditional culture of fishes versus slurry. This survey were conducted on nine pound of 1.7 hec triplicate with their treatment with stocking densities of 1.7 million fish larva at Dr yousefpoor center (Affiliated of Shahid Beheshti culture and propagation) at Siakal village , 32 km far from Rasht city in North of Iran, the first treatment considered as control which practice traditionally (using concentrated food plus grinded kilka fish) .In the second treatment for 13 days the pound supplied only by slurry then followed by concentrated fish food only .The tired treatment started with slurry for 13 days and followed by slurry plus concentrated food. The physical and chemical parameters of water, plankton, biometry of fish, growth indices such as daily weight growth (DWG), daily length growth (DLG) as well as specific ratio (SGR) were monitored weekly. The result indicate that net fish production was 1.7 to 2 times higher in slurry than traditional treatment also the survival rate were 1.7 times higher in slurry treatment . The treatment of slurry follow by addition of concentrated food plus slurry showed higher yield camper to others. Slurry with several active substances is more effective and can promote the growth of zooplanktons which is the food of larval stage of rutilus frisi kutum. In second phase of this project the effect of slurry was surveyed on Chinese carp. This experiment was conducted in triplicate with two treatment (one treatment is control which use cow manure plus chemical fertilizer and second treatment was conducted with slurry) and stocked with 2375 N/hec (Silver carp 60%, Big head 15%, common carp 17% and grass carp 8%) at June. In this survey common carp and grass carp were feed with concentrate food and fresh grasses respectively. Chemical factors were measured once for each two week and density of plankton was determined when it was necessarily. Nutritional content of phosphorous, nitrogen, calcium, potassium and magnesium after anaerobic fermentation as well as protein and lipid content with 1.4and 1.9 times respectively were higher in slurry treatment than control. The results showed that survival rate and yield were higher in slurry than control. The increasing percent of yield were 13.5, 2.6, 18.4 and 85.3 in Silver carp, Big head, common carp and grass carp respectively. The survival rate of grass carp was twice higher in slurry treatment than control. Zooplankton abundant in slurry pounds was more but blue- green algae density was less than control. Protein and lipid analysis reviled no significant difference between control and slurry. In general the result indicate that the slurry with higher nutritional content is more effective on the survival and growth rate of fishes and also is more efficient in proliferation of plankton in particular zooplankton.
    Keywords: Aquaculture ; Iran ; Caspian Sea ; Slurry ; Rutilus frisii kutum ; Cow fertilize ; Larviculture ; Carp ; Culture ; Plankton ; SGR ; Zooplanktons ; Silver Carp ; Big head carp ; Common carp ; Grass carp ; Phosphorous ; Nitrogen ; Survival rate ; Protein ; Lipid
    Repository Name: AquaDocs
    Type: monograph
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  • 11
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    Epidemiological study on some environmental and management parameters affecting on WSD occurrence in Fenneropenaeus indicus and Penaeus vannamei (2021)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25652 | 18721 | 2018-10-08 08:43:54 | 25652 | Iranian Fisheries Science Research Institute
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    Publication Date: 2021-07-16
    Description: For the first time white spot disease (WSD) was reported in shrimp farms of khoozestan province, in southwest of IRAN in 2002. Then in 2005 the neighbor province, boushehr, was contaminated. In 2008 WSD outbreak reported in sistan-bloochestan province in southeast of Iran. In 2015 all of southern shrimp farms of country except Hormozgan, the middle southern province, which has remained free of WSD, are being contaminated. White Spot disease suspended shrimp culture in thousands hectares of shrimp farms. Considering that white spot disease has not been observed in Hormozgan province yet, the question is; to what extent environmental and management factors participated in preventing WSD outbreak or cause WSD outbreak. In this study (20102012), the effects of environmental factors and management, stressors that decrease immune system function of shrimp are discussed. In addition, the role of pathogen as the main factor of outbreak is discussed. The goal of this study is to define environmental parameters and management practices associates with outbreak of white spot disease in affected provinces and discover reasons of being Hormozgan province free of this disease. In this study the role of the local environmental factors and management practice stressors in susceptibility to WSD was determine. Both the effects of environmental factors in water of ponds including total ammonia, nitrogen, dissolved oxygen, pH, salinity, transparency, and temperature and management issues related to biosecurity are studied. There were overlaps on physical and chemical parameter values obtained in clear areas with contaminated areas .Results of the data analysis suggest that lack of association with WSD incidence was 7 times greater than WSD incidence despite of disease outbreak in sistan-bloochestan province, so other sources of white spot disease virus incidence was suspected in affected areas. Histopathological examinations and polymerase chain reaction (PCR) tests during project performance did not reveal white spot disease virus evidences in post larvae examined from khoozestan province stocked in farms but disease outbreak was happened in that farms , so we suspected to management practice include feed , pond preparation and carrier of disease. Recorded values of temperature and salinity in some months during inspection in Hormozgan province specified stressful condition that may lead to WSD outbreak, however the disease did not appear. Therefore the hypothesis that the water physical and chemical conditions are reasons to prevent disease outbreak in Hormozgan province is being rejected. The policy of Hormozgan’s fishery authorities, to replaced Fenneropenaeus indicus with specific pathogen free Litopenaeus vannamei, that is more resistant to some of diseases, before incidence of WSD in farms and to before being endemic in the Hormozgan province, made an advantage compare to affected southern provinces that introduced Litopenaeus vannamei after WSD prevalence to their farms. However it does not guarantee to maintain current trend of being Hormozgan province farms free of white spot disease. Therefore establishing the principals of biosecurity are strongly emphasized. Strategies taken by the proficient authorities in preparation of SPF shrimp broodstock can be the most important factor in preventing WSD. Regarding biosecurity principals purchased feed must be free of shrimp head powder. Construction the new shrimp farms should be as far as it could be away from contaminated areas.
    Keywords: Aquaculture ; Ecology ; Health ; Iran ; Khouzestan Province ; Boushehr province ; Sistan and Balochestan province ; Hormozgan Province ; Epidemiological study ; WSD ; Fenneropenaeus indicus ; Penaeus vannamei ; Shrimp ; White Spot Disease ; Temperature ; Salinity ; PCR ; Polymerase Chain Reaction ; Ammonia ; Nitrogen ; Dissolved oxygen ; pH ; Transparency
    Repository Name: AquaDocs
    Type: monograph
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  • 12
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    Monitoring on nutrients of sediment with emphasis on algal bloom event in the southern of Caspian Sea (2021)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25657 | 18721 | 2018-10-08 08:23:30 | 25657 | Iranian Fisheries Science Research Institute
    Details
    Publication Date: 2021-07-16
    Description: This study was conducted to spatio-temporal fluctuation and distribution of phosphorous and nitrogen species, total organic carbone and some environmental parameters at suface sediments in the southern of Caspian Sea. In current study, 48 samples were collected from four stations (Bandar Anzali, Tonekabon, Bandar Nowshahr and Bandar Amirabad) and three dephths (5, 10 and 20 meter) during four seasons in 2013-2014. Results of this study showed that annual mean of Adsorbed-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Rese.-P and TP were obtained 6.68±0.63, 60.90±2.44, 24.94±2.39, 94.52±3.62, 1868±36, 1963±37, 87.51±9.52 and 2050±38 µg/g.dw, respectively. Result also showed that inorganic phophotous was maximum during different seasons, however, percent mean of residue-P which containe organic compounds and non-degrediable compounds, was less that 5 percent. Percent of Ca-P was higher than 90, whereas Bioava.-P was less that 10 percent. The order of different forms of phosphorous were registered Ca-P〉Org-P〉Fe-P〉Al-P〉Adsorbed-P.Annual mean of NH4/N, NO3/N, TIN, TON and TN were observed 2.56±0.27, 0.89±0.12, 3.52±0.26, 6.06±0.27 and 9.57±0.32µg/g.dw respectively. Annual percent of TON was two folds than TIN and NH4/N was also three times than NO3/N. In addition, mean of Fe, Al, Ca, Eh and TOC% were obtained 25.39±0.65, 18.76±0.68, 60.15±1.50 mg/g.dw and 67.02±0.68, 1.11±0.09, respectively. Maximum mean of carbon (1152±171), nitrogen (0.87±0.05) and phoporous (74±23) µM/g were observed in fall, winter and summer, recpectively. Also, maximum ratios of TOC:TP (16.8±2.3) and TOC:TN (2378±363) were obtained in fall season. As a conclusion, mian role of Adsorbed-P, Fe-P and Al-P adsorbed and desorbed were temperature, Eh and pH, respectively. Results of this study showed that TOC:TN was very high which represented to excitance of organic matter with almost non-degrediable. Whereas, TOC:TP was low which showed that organic phophoros was not related to proteins and phospholipids therefore sources of org-P were belong to other compounds.
    Keywords: Ecology ; Iran ; Caspian Sea ; Anzali ; Tonekabon ; Nowshahr ; Phophorous ; Carbon ; Nitrogen ; Environmental parameters ; Surface sediments ; Nutrients ; Algal bloom ; Species ; Samples ; Temperature ; pH ; Proteins ; Phospholipid
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    Study of water's physico-chemical characteristics in the southern Caspian Sea (2021)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25337 | 18721 | 2018-09-13 12:43:04 | 25337 | Iranian Fisheries Science Research Institute
    Details
    Publication Date: 2021-07-16
    Description: This study was conducted to determine the physico-chemical characteristics of water during four season and 8 transects (Astara, Anzali, Sefidroud, Tonekabon, Nowhshar, Babolsar, Amirabad, Bandar Tourkman) in the Southern of Caspian Sea in 2009-2010. 480 samples were collected at different water layers and then physicochemical parameters were measured based on standard methods. Result of this study showed that surface water temperature was varied from 7.2 to 29.8◦C in winter and summer, respectively. Minimum fluctuation of water temperature was observed at 100 m depth (6.8-10.3◦C). Mean value of water transparency was obtained 4.91±0.24 m. This value increased from inshore to offshore. pH value was fluctuated from 7.15 to 8.83 unit with variance of 1.54. Maximum DO concentration was observed at surface layer (8.40±0.08 mg/l) with 137±18 saturation and minimum was at 100 m depth (6.46±0.18) with 86.1±2.8 saturation. The nitrite, nitrate and ammonium concentration were ranged 0.0-0.2, 0.0-4.6 and 0.05-7.12 µM, respectively. Maximum value of TN was observed at inshore and minimum at offshore (100m). Nitrite concentration decreased from inshore to offshore but increased from surface to the bottom (100 m). The inorganic phosphorous increased at surface water and also at the bottom. Trend of inorganic and TP was similar. Minimum of N/P ratio were observed at summer (5.48±0.38) and maximum value at winter (9.13±0.46). This value of N/P ratio showed that the growth of phytoplankton was limited by nitrogen. The dissolved silicate was decreased from spring (230.7±6.65 µg/l) to winter.
    Keywords: Ecology ; Iran ; Caspian Sea ; Astara ; Anzali ; Tonekabon ; Nowhshar ; Babolsar ; Bandar Tourkman ; Sefiroud River ; Water ; Physico-chemical parameters ; Temperature ; pH ; Phosphorous ; Phytoplankton ; Nitrogen ; Dissolved silicate ; Fluctuation
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  • 14
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    Improvement the texture properties and acceptability of silver carp investigation on possibility of burger by addition pectin in the fish burger material (2021)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25489 | 18721 | 2018-10-05 06:51:09 | 25489 | Iranian Fisheries Science Research Institute
    Details
    Publication Date: 2021-07-16
    Description: In this study the physical properties of silver carp burger over a period of six months at a temperature of -18 ċ were studied using pectin. Indicators such as hardness texture, juiciness, flavor and overall acceptance of the product containing. The product were evaluated using qualified assessors، the microbial, chemical markers to evaluate the qualitative change such as peroxide treatments, total volatile nitrogen bases ، total count of bacteria and examined psychotropic of tests six months of treatments carried out on a monthly basis. The results indicate that the addition of pectin 0.3 percent of total admissions acceptance of burgers tissue was obtained and significant differences are. The chemical test results were also increased with storage time burger in refrigerators -18 degrees. Range of volatile nitrogen bases out of 15.2±1.2 at the time of 26/5±1.17 mg/100, the peroxide from 0.6±0.61 to 3/56±0.6 meq/kg of oxygen was. Thus despite a significant increase in indicators of physical Chemical and sensory evaluation of texture analysis. In the past six months storage period of -18 degrees, burger productive uses of pectin 0/3 percent of the limit between acceptable and will was.
    Keywords: Fisheries ; Burgers ; Fish ; Silver Carp ; Storage ; Quality ; Changes ; The shelf life ; Texture ; Pectin ; Nitrogen ; Bacterial ; Psychotropic
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    Determination of sediment nutrients in the cage fish culture area (before breeding) of the southern Caspian Sea (Mazandaran coast-Kelarabad) (2021)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25755 | 18721 | 2018-10-13 06:22:22 | 25755 | Iranian Fisheries Science Research Institute
    Details
    Publication Date: 2021-07-16
    Description: This study was conducted to determine phosphorous and nitrogen species at the surface sediment in the southern Caspian Sea (Mazandaran Coast, Kelarabad). Surface sediments samples were collected at three stations from autumn of 2011 to winter of 2012. All samples were prepared by digesting and extracting processes and then phosphorous and nitrogen species concentrations determined using spectroscopy instrument. Results of this study showed that annual mean of Loosely-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Rese.-P and TP was obtained as 5.06±0.33, 55.11±2.52, 42.38±3.74, 102.52±5.68, 172.91±7.12, 275±9.12, 333.30±28.52 and 608±52 µg/g.dw, respectively. The results also showed that inorganic phophorous was less than organic phophorous during different seasons, however, mean percentage of residue-P containing organic compounds and non-degradable compounds was more than 50 percent. Percentage of Ca-P was higher than 60, whereas Bioava.-P was less than 40 percent. In addition, Fe-P and Loosely-P attained the maximum and minimum values, respectively, among the bioavailable phophorous. The order of different forms of phosphorous were recorded as Org-P〉Ca-P〉FeP〉Al-P〉Loosely-P. Annual mean of NH4/N, NO2/N, NO3/N, TIN, TON and TN were observed as 4.23±0.50, 0.06±0.01, 0.74±0.12, 5.02±0.53, 2.48±0.63 and 7.53±0.51 µg/g.dw, respectively. Annual percentage of TIN was two folds than TON and concentration of NH4/N was also four times than NO3/N. As a conclusion, the results revealed that main causes of Bioava.-P adsorption and desorption were temperature, Eh and pH. Also, the form of NH4+/N was of a high percentage because of anaerobic condition in the sediments. According to the high ratios of nitrogen/phosphorous of sediments to nitrogen and phosphorous of bottom water, it finds that released of those from the sediments to water will be happened with high rates. Therefore, it is expected that the establishment of fish farming cages should be carried out with more precautionary approaches which not leads to increased algae bloom.
    Keywords: Biology ; Chemistry ; Ecology ; Iran ; Caspian Sea ; Kelarabad ; Mazandaran coast ; Phophorous ; Nitrogen ; Surface sediment ; Determination ; Breeding
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  • 16
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    Estimated un-ionized ammonia at small incremental pH value and temperatures: practical option for fish farmers (2021)
    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24235 | 19325 | 2018-05-20 05:20:54 | 24235 | Fisheries Society of Nigeria
    Details
    Publication Date: 2021-07-15
    Description: Ammonia as the primary product of nitrogen metabolism causes mortality due to ammonia toxicity produced in a culture system. Effect of pH and Temperature was calculation and expanded using the acid dissociation constant (pka) for equation: pka = 0.09018+ 2729.92/T. Ammonia values (f) expressed in percents for intervals of 1.0 degree from 0 - 30~'C and pH increasing from pH 6-10 where T is the Temperature and acid dissociation constant (pka). Ammonia (f) was calculated using the equation: f= 1/(10pka-pH+1).Small increments of 0.5 were considered from pH values of 3.0 - 7.0 for Temperature range of 20 - 34~'C as experienced now in most farms in Lagos. Casio scientific calculator fx-82TL (12 Digits) with four significant figures was used for the calculation. The acid dissociation constant (Pka) calculated for 31-34~'C was 9.0702, 9.0407, 9.0115 and 8.9824 respectively. pH and Temperature can be monitored and used for ammonia estimation by cross-marching with the extended pH -Temperature Emerson monogram. This will show the estimated ammonia as observed for pH and Temperature at pH 6.0 - 7.0. The use of this management protocol (Monogram) will reduce mortality in culture systems serving as a prompt management tool for fish farm operation. The understanding of the usage of this monogram will reduce the cost of production usually necessitated by non availability and high cost of imported water quality, which many farmers cannot afford.
    Description: Includes: 12 references.
    Keywords: Aquaculture ; Nigeria ; Lagos State ; Ammonia ; Acid dissociation constant ; (pksuba/sub) ; pH ; Temperature ; marine environment ; Ammonia ; Nitrogen ; Metabolism ; Toxicity ; pH effects ; Acidity ; Fish culture ; Monitoring ; Baseline studies ; Mortality ; Reduction ; Temperature tolerance
    Repository Name: AquaDocs
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    Spatial and Seasonal Nutrient Trends in Manila Bay Aquaculture Farms (2021)
    In:  http://aquaticcommons.org/id/eprint/26984 | 25026 | 2020-03-05 01:26:54 | 26984 | National Fisheries Research and Development Institute, Philippines
    Details
    Publication Date: 2021-07-24
    Description: Sampling was done in duplicates during dry (May 2014 and February 2015) and wet season (September 2014 and November 2014) following the blocking scheme for the nutrient trends. As for the nutrient loading, water samples were collected in three ponds after flooding (water intrusion) and prior to draining (water release). Colorimetric analyses by UV-Vis Spectroscopy following the US EPA standard methods were used to determine the samples’ nutrient levels specifically, ammonia, nitrate, nitrite, and phosphorus. Results showed that ammonia had the highest levels followed by phosphorus, nitrate, and nitrite. Geographically, higher concentration of nitrogen and phosphorus were observed in Eastern Bulacan aquaculture farms, which is attributed to the farmers’ disregard of the important pond preparation activities. Varying seasonal trends were noted among nutrient species due to the different reactions of each analyte under changing climatic conditions. Nutrient levels in sediments were several folds higher than that in the water column. Results of correlation analyses of nutrients in water and sediments showed: a) a good correlation for phosphorus, b) weak correlation for ammonia, and c) no correlation for nitrites and nitrates, implying that sediments maybe a possible contributor of phosphorus and ammonia in water but not nitrite and nitrate. Ammonia and TKN were significantly higher during the flooding suggesting that water coming in to the pond already contains high levels of said nutrients possibly due to higher organic load. Conversely, nitrite and nitrate levels were significantly higher during the draining suggesting transformation of ammonia into these less toxic substances by nitrifying bacteria.
    Keywords: Aquaculture ; Chemistry ; Fisheries ; Oceanography ; Aquaculture ; Nitrogen ; Phosphorus ; Manila Bay
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    Nutrient Limitation of Periphyton in a Spring-Fed, Coastal Stream in Florida, USA. (2021)
    In:  http://aquaticcommons.org/id/eprint/1642 | 3 | 2011-09-29 20:15:42 | 1642 | Aquatic Plant Management Society, Inc.
    Details
    Publication Date: 2021-07-09
    Description: There is strong evidence to suggest that ground-waternitrate concentrations have increased in recent years andfurther increases are expected along portions of the centralGulf coast of Florida. Much of the nitrate enriched groundwateris discharged into surface waters through numerousfreshwater springs that are characteristic of the area and thepotential for eutrophication of their receiving waters is alegitimate concern. To test the potential effects of elevatednutrient concentrations on the periphyton community aninsitunutrient addition experiment was conducted in thespring-fed Chassahowitzka River, FL, USA, during the summerof 1999. Plastic tubes housing arrays of glass microscopeslides were suspended in the stream. Periphyton colonizingthe microscope slides was subjected to artificial increases innitrogen, phosphorus or a combination of both. Slides fromeach tube were collected at 3- to 4- day intervals and theperiphyton communities were measured for chlorophyll concentration.The addition of approximately 10 μg/L of phosphateabove ambient concentrations significantly increasedthe amount of periphyton on artificial substrates relative tocontrols; the addition of approximately 100 μg/L of nitrateabove ambient concentrations did not. The findings fromthis experiment implicated phosphorus, rather thannitrogen, as the nutrient that potentially limits periphytongrowth in this system.(PDF contains 4 pages.)
    Description: January 2003
    Keywords: Management ; Biology ; Limnology ; Nitrogen ; Phosphorus ; Bioassay ; Eutrophication ; Nutrient Enrichment ; Chassahowitzka River ; Florida ; springs
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    Spatial mapping of sedimentary contaminants in the Baltimore Harbor/Patapsco river/Back river system (2021)
    University of Maryland Center for Environmental Science. Chesapeake Biological Laboratory | Solomons, MD
    In:  http://aquaticcommons.org/id/eprint/2883 | 130 | 2011-09-29 18:17:42 | 2883 | University of Maryland Center for Environmental Science. Chesapeake Biological Laboratory
    Details
    Publication Date: 2021-06-29
    Description: Primary objective was to map concentrations of target contaminants in the surfacial sediments. Secondary objectives included: characterization of potential sites for sediment capping demonstration projects, further characterization of sediment depositional and accumulation patterns, and estimation of historical contaminant inventories through sediment geochronology. (PDF contains 112 pages)
    Description: Maryland Department of the Environment
    Keywords: Ecology ; Pollution ; Environment ; Chemistry ; Polychlorinated biphenyls ; Polycyclic aromatic hydrocarbons ; organochlorine pesticides ; Mercury ; Methylmercury ; Nitrogen ; Sulfur ; Trace metals ; toxic effects ; Chesapeake Bay ; Baltimore Harbor ; Patapsco river ; Back river ; Maryland ; carbon ; PCB ; Cadmium ; Chromium ; Nickel ; Copper ; Zinc
    Repository Name: AquaDocs
    Type: monograph
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  • 20
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    Nitrates in surface water, inputs and seasonality (2021)
    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5222 | 1256 | 2011-09-29 15:12:09 | 5222 | Freshwater Biological Association
    Details
    Publication Date: 2021-07-09
    Description: Because of the widespread concern over increasing nitrate concentrations in river water , the Freshwater Biological Association has undertaken a study to investigate seasonality, nitrate concentrations and loads in the River Frome catchment in relation to land use and compare the results for 1984/86 with data obtained in 1970/71. Information on land use changes and fertiliser applications were obtained both from MAFF and individual farmers. The study concludes that input of nitrogen from rainfall to the River Frome catchment had not significantly changed between 1970/71 and 1984/86.
    Keywords: Ecology ; Limnology ; Pollution ; Rivers ; Nitrogen ; Rain ; River discharge ; Monitoring ; Sewage ; Nitrates ; Fertilizers ; England ; Frome River
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  • 21
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    The culture of algae and its applications (2021)
    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5108 | 3949 | 2011-09-29 15:23:52 | 5108 | Freshwater Biological Association
    Details
    Publication Date: 2021-07-08
    Description: An article explaining how the methods and results from the time spent by the author culturing algae can be applied to other algal investigations. The work by the author found that physiological requirements differ widely among algae belonging to different systematic groups. Details are given of the results of a series of experiments which were undertaken in solutions with similar proporties to some natural waters in the Lake District. Reference is made to a paper under preparation at that time containing data on phytoplankton studied in the field within the Lake District during 1937. Reference is also made to Loch Leven and the affects of bluegreen alga on the number of trout caught weekly during 1937.
    Keywords: Biology ; Limnology ; Laboratory culture ; Plant physiology ; Algal culture ; Algae ; Freshwater fish ; Nitrogen ; Annual reports ; England ; Scotland
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    Identifying and assessing effectiveness of alternative low-effort nitrogen footprint reductions in small research institutions (2021)
    IOP Publishing
    Details
    Publication Date: 2022-10-27
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Messenger, S., Lloret, J., Galloway, J. N., & Giblin, A. Identifying and assessing effectiveness of alternative low-effort nitrogen footprint reductions in small research institutions. Environmental Research Letters, 16(3), (2021): 035014, https://doi.org/10.1088/1748-9326/abd9f6.
    Description: Concern over the ecological damage of excess nitrogen has brought increased attention to the role of research institutions and universities in contributing to this problem. Institutions often utilize the concept of the ecological 'footprint' to quantify and track nitrogen emissions resulting from their activities and guide plans and commitments to reduce emissions. Often, large-scale changes and commitments to reduce nitrogen footprints are not feasible at small institutions due to monetary and manpower constraints. We partnered with managers in the dining and facilities departments at the Marine Biological Laboratory (MBL), a small research institution in Woods Hole, Massachusetts, to develop five low-effort strategies to address nitrogen emissions at the institution using only resources currently available within those departments. Each proposed strategy achieved emissions reductions in their sector and in the overall nitrogen footprint of the MBL. If all modelled strategies are applied simultaneously, the MBL can achieve a 7.7% decrease in its nitrogen footprint. Managers at MBL considered strategies that required no monetary input most feasible. The intersection of carbon and nitrogen emissions also means the modelled strategies had the co-benefit of reducing the MBL's carbon footprint, strengthening the argument for applying these strategies. This paper may serve as a model for similar institutions looking to reduce the ecological impact of their activities.
    Description: The work of the Nitrogen Footprint Tool Network was supported by Cooperative Agreement No. 83563201 awarded by the U.S. Environmental Protection Agency.
    Keywords: Nitrogen ; Nitrogen footprint ; Small institutions ; Low-effort
    Repository Name: Woods Hole Open Access Server
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    Basic aspects of the biogenic elements balance in the Azov Sea (2020)
    Details
    Publication Date: 2021-05-19
    Description: This article presents the basic aspects of the dynamics of biogenic elements in the Azov Sea, based on literature data and our field research, conducted recently in different seasons of the year from 1998 to 2018. Correlation relationships of the main factors, affecting the change in the content of biogenic salts, are presented, and seasonal aspects of the dynamics of the mineral forms of nitrogen, phosphorus and silicon are given. It has been established that the Taganrog Bay is affected by the Don River flow to a greater measure, and in the sea, the significant role in the dynamics of biogenic elements is played by intrabasin processes. The importance of the river flow influence is shown by the supply of biogenic elements to the Taganrog Bay, in which not only the volume of river flow but also the general antrhopogenic pressure on the Lower Don and the Taganrog Bay area are crucial factors. Bottom hypoxia in the summer season plays a prominent role in enriching the water column with phosphates and ammonium nitrogen. In estimation of the dynamics of biogenic elements in the Azov Sea, the seasonal processes of mineralization of organic substances, the rate of recycling of biogenic compounds, life cycle of phytoplankton, wind speed over the sea surface, formation of density and oxygen stratification of water masses, water exchange with the Black Sea, bottom sedimentation, outwashing from rock material, and introduction of elements with atmospheric precipitations should also be taken into account. All factors, affecting the change in the concentration of mineral forms of nitrogen, phosphorus and silicon in water, are given in the form of flowcharts.
    Description: В статье представлены основные аспекты баланса биогенных веществ в Азовском море на основе литературных данных и собственных экспедиционных исследований, проведенных в современный период с 1998 по 2018 г. в разные сезоны года. Приведены корреляционные взаимосвязи основных факторов, влияющих на изменение содержания биогенных солей, и представлены сезонные аспекты динамики минеральных форм азота, фосфора и кремния. Установлено, что Таганрогский залив в большей степени подвержен влиянию стока р. Дон, а в собственно море существенную роль в балансе биогенных элементов играют внутриводоемные процессы. Важность влияния речного стока показана в обеспечении Таганрогского залива биогенными элементами; при этом существенную роль играет не только объем речного стока, но и общая антропогенная нагрузка на акваторию Нижнего Дона и Таганрогского залива. Придонная гипоксия в летний период года на акватории собственно моря обеспечивает обогащение водной толщи фосфатами и аммонийным азотом. При оценке баланса биогенных элементов в Азовском море необходимо учитывать также сезонные процессы минерализации органических веществ, скорость рециклинга биогенных соединений, жизненный цикл фитопланктона, скорость ветра над акваторией, формирование плотностной и кислородной стратификации водных масс, водообмен с Черным морем, седиментацию в донные отложения, вымывание с горных пород, поступление с атмосферными осадками. Все факторы, оказывающие воздействие на изменение концентраций в воде минеральных форм азота, фосфора и кремния, приведены в виде блок-схем.
    Description: Published
    Keywords: Biogenic matter ; Nitrogen ; Seasonal variations ; Phosphorus ; Silicon ; Phytoplankton ; Life cycle ; Bottom sediments ; Water column ; Sea surface ; Водная толща ; Фосфор ; Кремний ; Жизненный цикл ; Фитопланктон ; Поверхностный слой ; Донные отложения ; Сезонная динамика
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
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    Nitrite Oxidoreductase targeted metaproteomics from R/V Kilo Moana cruise KM1128 and R/V Falkor cruise FK160115 in the Central Pacific Ocean in 2011 and 2016 (2020)
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Details
    Publication Date: 2022-10-31
    Description: Dataset: Pacific Nitrite Oxidoreductase
    Description: Nitrite Oxidoreductase targeted metaproteomics from R/V Kilo Moana cruise KM1128 and R/V Falkor cruise FK160115 in the Central Pacific Ocean in 2011 and 2016. NxrA and NxrB peptide concentrations in fmol/L. Peptide names are using the GEOTRACES naming convention (PEP for peptide, full tryptic peptide amino acid sequence, Protein name, Sampling device (=Pump)). Quality flags follow each peptide column and use the GEOTRACES convention of 1 for good, 6 for below detection limit. These data were published in Saito et al., 2020 as Supplementary Table 1. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/806510
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1031271, Gordon and Betty Moore Foundation: Marine Microbiology Initiative (MMI) GBMF3782, NSF Division of Ocean Sciences (NSF OCE) OCE-1657766, NSF Division of Ocean Sciences (NSF OCE) OCE-1736599, NSF Division of Ocean Sciences (NSF OCE) OCE-1850719, NSF Division of Ocean Sciences (NSF OCE) OCE-1924554
    Keywords: Nitrite ; Nitrogen ; Enzyme ; Iron ; ProteOMZ ; Metzyme
    Repository Name: Woods Hole Open Access Server
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  • 25
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    Discrete hydrographic measurements - Effects of Hurricane Harvey on Estuarine Water Quality in the Lavaca-Colorado, Guadalupe and Nueces Estuaries between August 2017 and January 2018. (2020)
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Details
    Publication Date: 2022-10-31
    Description: Dataset: Wetz-783256-Discrete
    Description: Discrete hydrographic measurements of Lavaca-Colorado, Guadalupe and Nueces Estuaries on the Texas coast between August 2017 and January 2018. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/787316
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1760006
    Keywords: Hurricane Harvey ; Freshwater Inflow ; Flooding ; Water quality ; Texas Coast ; Estuary ; Salinity ; Temperature ; Dissolved oxygen ; Chlorophyll ; Nutrients ; Nitrogen ; Carbon
    Repository Name: Woods Hole Open Access Server
    Type: Dataset
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  • 26
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    An evaluation of the C/N ratio of the mantle from natural CO2-rich gas analysis: Geochemical and cosmochemical implications (2020)
    Elsevier
    Details
    Publication Date: 2022-10-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marty, B., Almayrac, M., Barry, P. H., Bekaert, D., V., Broadley, M. W., Byrne, D. J., Ballentine, C. J., & Caracausi, A. An evaluation of the C/N ratio of the mantle from natural CO2-rich gas analysis: Geochemical and cosmochemical implications. Earth and Planetary Science Letters, 551, (2020): 116574, doi:10.1016/j.epsl.2020.116574.
    Description: The terrestrial carbon to nitrogen ratio is a key geochemical parameter that can provide information on the nature of Earth's precursors, accretion/differentiation processes of our planet, as well as on the volatile budget of Earth. In principle, this ratio can be determined from the analysis of volatile elements trapped in mantle-derived rocks like mid-ocean ridge basalts (MORB), corrected for fractional degassing during eruption. However, this correction is critical and previous attempts have adopted different approaches which led to contrasting C/N estimates for the bulk silicate Earth (BSE) (Marty and Zimmermann, 1999; Bergin et al., 2015). Here we consider the analysis of CO2-rich gases worldwide for which a mantle origin has been determined using noble gas isotopes in order to evaluate the C/N ratio of the mantle source regions. These gases experienced little fractionation due to degassing, as indicated by radiogenic 4He / 40Ar* values (where 4He and 40Ar* are produced by the decay of U+Th, and 40K isotopes, respectively) close to the mantle production/accumulation values. The C/N and C/3 He ratios of gases investigated here are within the range of values previously observed in oceanic basalts. They point to an elevated mantle C/N ratio (∼350-470, molar) higher than those of potential cosmochemical accretionary endmembers. For example, the BSE C/N and 36 Ar / N ratios (160-220 and 75 x 10-7, respectively) are higher than those of CM-CI chondrites but within the range of CV-CO groups. This similarity suggests that the Earth accreted from evolved planetary precursors depleted in volatile and moderately volatile elements. Hence the high C / N composition of the BSE may be an inherited feature rather than the result of terrestrial differentiation. The C / N and 36 Ar / N ratios of the surface (atmosphere plus crust) and of the mantle cannot be easily linked to any known chondritic composition. However, these compositions are consistent with early sequestration of carbon into the mantle (but not N and noble gases), permitting the establishment of clement temperatures at the surface of our planet.
    Description: M.A, D.V.B, M.W.B, D.J.B and B.M were supported by the European Research Council (PHOTONIS project, grant agreement No. 695618 to B.M.). Samples were collected as part of Study # YELL-08056 - Xenon anomalies in the Yellowstone Hotspot. We would like to thank Annie Carlson and all of the rangers at the Yellowstone National Park for providing invaluable advice and help when collecting the samples. This work was partially supported by a grant (G-2016-7206) from the Alfred P. Sloan Foundation and the Deep Carbon Observatory to P.H.B as well as NSF award 2015789 to P.H.B.. Sampling at Mt. Etna and gas analysis was supported by Instituto Nazionale di Geofisica e Vulcanologia Palermo. Fruitful discussions with Marc Hirschmann helped us to shape the ideas presented in this work. We acknowledge detailed and insightful reviews by Sami Mikhail and an anonymous reviewer, and efficient editing by Frederic Moynier. This is CRPG contribution 2741.
    Keywords: Carbon ; Nitrogen ; Earth ; Mantle ; Gases
    Repository Name: Woods Hole Open Access Server
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    Investigating boron isotopes for identifying nitrogen sources supplied by submarine groundwater discharge to coastal waters (2020)
    Frontiers Media
    Details
    Publication Date: 2022-10-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Tamborski, J., Brown, C., Bokuniewicz, H., Cochran, J. K., & Rasbury, E. T. Investigating boron isotopes for identifying nitrogen sources supplied by submarine groundwater discharge to coastal waters. Frontiers in Environmental Science, 8, (2020): 126, doi:10.3389/fenvs.2020.00126.
    Description: Stable isotopes of oxygen, nitrogen, and boron were used to identify the sources of nitrate (NO3–) in submarine groundwater discharge (SGD) into a large tidal estuary (Long Island Sound, NY, United States). Potential contaminants such as manure, septic waste and fertilizer overlap in δ15N and δ18O but have been shown to have distinctive δ11B in non-coastal settings. Two distinct subterranean estuaries were studied with different land-use up gradient, representative of (1) mixed medium-density residential housing and (2) agriculture. These sites have overlapping δ15N and δ18O measurements in NO3– and are unable to discriminate between different N sources. Boron isotopes and concentrations are measurably different between the two sites, with little overlap. The subterranean estuary impacted by mixed medium-density residential housing shows little correlation between δ11B and [B] or between δ11B and salinity, demonstrating that direct mixing relationships between fresh groundwater and seawater were unlikely to account for the variability. No two sources could adequately characterize the δ11B of this subterranean estuary. Groundwater N at this location should be derived from individual homeowner cesspools, although measured septic waste has much lower δ11B compared to the coastal groundwaters. This observation, with no trend in δ11B with [B] indicates multiple sources supply B to the coastal groundwaters. The agricultural subterranean estuary displayed a positive correlation between δ11B and [B] without any relationship with salinity. Binary mixing between sea spray and fertilizer can reasonably explain the distribution of B in the agricultural subterranean estuary. Results from this study demonstrate that δ11B can be used in combination with δ15N to trace sources of NO3– to the subterranean estuary if source endmember isotopic signatures are well-constrained, and if the influence of seawater on δ11B signatures can be minimized or easily quantified.
    Description: This research was funded by New York Sea Grant projects R/CMC-13 and R/CMC-13-NYCT. The MC-ICP-MS used for this work was funded through NSF-MRI 0959524.
    Keywords: Submarine groundwater discharge ; Boron ; Nitrogen ; Nitrate ; Fertilizer ; Wastewater ; Septic waste
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    Radium mass balance sensitivity analysis for submarine groundwater discharge estimation in semi-enclosed basins: the case study of Long Island Sound (2020)
    Frontiers Media
    Details
    Publication Date: 2022-10-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Tamborski, J., Cochran, J. K., Bokuniewicz, H., Heilbrun, C., Garcia-Orellana, J., Rodellas, V., & Wilson, R. Radium mass balance sensitivity analysis for submarine groundwater discharge estimation in semi-enclosed basins: the case study of Long Island Sound. Frontiers in Environmental Science, 8, (2020): 108, doi:10.3389/fenvs.2020.00108.
    Description: Estimation of submarine groundwater discharge (SGD) to semi-enclosed basins by Ra isotope mass balance is herein assessed. We evaluate 224Ra, 226Ra, and 228Ra distributions in surface and bottom waters of Long Island Sound (CT-NY, United States) collected during spring 2009 and summer 2010. Surface water and bottom water Ra activities display an apparent seasonality, with greater activities during the summer. Long-lived Ra isotope mass balances are highly sensitive to boundary fluxes (water flux and Ra activity). Variation (50%) in the 224Ra, 226Ra, and 228Ra offshore seawater activity results in a 63–74% change in the basin-wide 226Ra SGD flux and a 58–60% change in the 228Ra SGD flux, but only a 4–9% change in the 224Ra SGD flux. This highlights the need to accurately constrain long-lived Ra activities in the inflowing and outflowing water, as well as water fluxes across boundaries. Short-lived Ra isotope mass balances are sensitive to internal Ra fluxes, including desorption from resuspended particles and inputs from sediment diffusion and bioturbation. A 50% increase in the sediment diffusive flux of 224Ra, 226Ra, and 228Ra results in a ∼30% decrease in the 224Ra SGD flux, but only a ∼6–10% decrease in the 226Ra and 228Ra SGD flux. When boundary mixing is uncertain, 224Ra is the preferred tracer of SGD if sediment contributions are adequately constrained. When boundary mixing is well-constrained, 226Ra and 228Ra are the preferred tracers of SGD, as sediment contributions become less important. A three-dimensional numerical model is used to constrain boundary mixing in Long Island Sound (LIS), with mean SGD fluxes of 1.2 ± 0.9 × 1013 L y–1 during spring 2009 and 3.3 ± 0.7 × 1013 L y–1 during summer 2010. The SGD flux to LIS during summer 2010 was one order of magnitude greater than the freshwater inflow from the Connecticut River. The maximum marine SGD-driven N flux is 14 ± 11 × 108 mol N y–1 and rivals the N load of the Connecticut River.
    Description: This project has been funded by New York Sea Grant projects (R/CCP-16 and R/CMC-12). This research is contributing to the ICTA-UAB Unit of Excellence “María de Maeztu” (MDM-2015-0552) and MERS (2017 SGR – 1588, Generalitat de Catalunya). VR acknowledges financial support from the Beatriu de Pinós postdoctoral program of the Catalan Government (2017-BP-00334).
    Keywords: Radium isotopes ; Submarine groundwater discharge ; Porewater exchange ; Nitrogen ; Long Island Sound
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    Quantifying oxygen management and temperature and light dependencies of nitrogen fixation by Crocosphaera watsonii (2020)
    American Society for Microbiology
    Details
    Publication Date: 2022-10-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Inomura, K., Deutsch, C., Wilson, S. T., Masuda, T., Lawrenz, E., Lenka, B., Sobotka, R., Gauglitz, J. M., Saito, M. A., Prášil, O., & Follows, M. J. Quantifying oxygen management and temperature and light dependencies of nitrogen fixation by Crocosphaera watsonii. Msphere, 4(6), (2019): e00531-19, doi: 10.1128/msphere.00531-19.
    Description: Crocosphaera is a major dinitrogen (N2)-fixing microorganism, providing bioavailable nitrogen (N) to marine ecosystems. The N2-fixing enzyme nitrogenase is deactivated by oxygen (O2), which is abundant in marine environments. Using a cellular scale model of Crocosphaera sp. and laboratory data, we quantify the role of three O2 management strategies by Crocosphaera sp.: size adjustment, reduced O2 diffusivity, and respiratory protection. Our model predicts that Crocosphaera cells increase their size under high O2. Using transmission electron microscopy, we show that starch granules and thylakoid membranes are located near the cytoplasmic membranes, forming a barrier for O2. The model indicates a critical role for respiration in protecting the rate of N2 fixation. Moreover, the rise in respiration rates and the decline in ambient O2 with temperature strengthen this mechanism in warmer water, providing a physiological rationale for the observed niche of Crocosphaera at temperatures exceeding 20°C. Our new measurements of the sensitivity to light intensity show that the rate of N2 fixation reaches saturation at a lower light intensity (∼100 μmol m−2 s−1) than photosynthesis and that both are similarly inhibited by light intensities of 〉500 μmol m−2 s−1. This suggests an explanation for the maximum population of Crocosphaera occurring slightly below the ocean surface.
    Description: We thank Stephanie Dutkiewicz and Sallie W. Chisholm for useful discussion, Martin Lukeš for technical assistance for the N2 fixation measurement, and the members of Writing and Communication Center at MIT for their advice on writing. This research was supported by the Japan Student Service Organization (JASSO) (grant L11171020001 to K.I.), the Gordon and Betty Moore Foundation (grant GBMF 3775 to C.D. and grant GBMF 3778 to M.J.F.), the U.S. National Science Foundation (grant OCE-1756524 to S.T.W., grant OCE-1558702 to M.J.F., and grant OCE-PRF 1421196 to J.M.G), the Simons Foundation (Simons Postdoctoral Fellowship in Marine Microbial Ecology award 544338 to K.I., Simons Collaboration on Ocean Processes and Ecology award 329108 to M.J.F., Simons Collaboration on Computational BIOgeochemical Modeling of Marine EcosystemS [CBIOMES] award 549931 to M.J.F.), the Czech Science Foundation (GAČR) (grant 16-15467S to O.P.), and the National Sustainability Programme (NPU) (grant LO1416 Algatech plus to O.P.).
    Keywords: Crocosphaera ; Carbon ; Cell flux model ; Daily cycle ; Iron ; Light ; Nitrogen ; Nitrogen fixation ; Oxygen ; Photosynthesis ; Temperature
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    The effect of different Nitrogen sources on growth rate and protein content of Spirulina platensis (2019)
    Details
    Publication Date: 2021-05-19
    Description: Nitrogen is known to have a strong influence on the metabolism of lipids and protein in various microalgae. In the present study, the production of S. platensis was optimized in terms of biomass and protein by using different Nitrogen sources as NH_4Cl, NH_4NO_3 and Urea. S. platensis was grown in Zarrouk’s medium in a 3000 ml Erlenmeyer flask, in which the NaNO_3 was replaced by NH_4Cl, NH_4N_O3 and Urea with concentrations of 0.010, 0.025 and 0.050 M. Cultures were incubated at temperature of 30oC, salinity of 25 ppt and initial pH of 9.5 under 12/12 hour light-dark photo period with normal white light. The results clearly showed that S. platensis successfully cultivated by using different Nitrogen regimes, and though the maximum biomass was produced in medium containing NH_4NO_3, but there is not significant differences between treatments (p〉0.05). The maximum protein content was obtained in culture containing NH_4NO_3 followed by NH_4Cl and KNO_3, and there is not significant differences between treatments (p〉0.05). Moreover, in all S. platensis cultures, increasing in nitrogen concentrations, led to an increase in maximum biomass and protein content. The chl. content increased with increasing Nitrogen concentrations in all treatments and relatively high values (9.18 µg/ml) were found with KNO_3 as a Nitrogen source at 14th day of culturing period. Overall, though the results of present study clearly showed no significant differences between treatments, but using of NH_4NO_3 could have relatively more effectiveness than the other Nitrogen sources.
    Description: Published
    Keywords: Spirulina platensis ; Biomass ; Protein ; Nitrogen
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.57-65
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    Nitrogen cycle patterns during forest regrowth in an African Miombo woodland landscape (2019)
    American Geophysical Union
    Details
    Publication Date: 2022-10-27
    Description: Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Biogeosciences, 124(6), (2019): 1591-1603, doi:10.1029/2018JG004803.
    Description: Tropical dry forests in eastern and southern Africa cover 2.5 × 106 km2, support wildlife habitat and livelihoods of more than 150 million people, and face threats from land use and climate change. To inform conservation, we need better understanding of ecosystem processes like nutrient cycling that regulate forest productivity and biomass accumulation. Here we report on patterns in nitrogen (N) cycling across a 100‐year forest regrowth chronosequence in the Tanzanian Miombo woodlands. Soil and vegetation indicators showed that low ecosystem N availability for trees persisted across young to mature forests. Ammonium dominated soil mineral N pools from 0‐ to 15‐cm depth. Laboratory‐measured soil N mineralization rates across 3‐ to 40‐year regrowth sites showed no significant trends and were lower than mature forest rates. Aboveground tree N pools increased at 6 to 7 kg N·ha−1·yr−1, accounting for the majority of ecosystem N accumulation. Foliar δ15N 〈0‰ in an N‐fixing canopy tree across all sites suggested that N fixation may contribute to ecosystem N cycle recovery. These results contrast N cycling in wetter tropical and Neotropical dry forests, where indicators of N scarcity diminish after several decades of regrowth. Our findings suggest that minimizing woody biomass removal, litter layer, and topsoil disturbance may be important to promote N cycle recovery and natural regeneration in Miombo woodlands. Higher rates of N mineralization in the wet season indicated a potential that climate change‐altered rainfall leading to extended dry periods may lower N availability through soil moisture‐dependent N mineralization pathways, particularly for mature forests.
    Description: This study depended on the knowledge, insights, and cooperation of many people and institutions. We thank the Millennium Villages Project‐Mbola site for providing introductions to the landscape and village headmen in many regions. We thank the ARI‐Tumbi staff (now TARI‐Tumbi) in Tabora, Tanzania for providing invaluable logistical support in identifying forest regrowth sites and help with labwork in Tabora, Tanzania. We thank other key local organizations, including Tabora Development Foundation Trust (Dick Mlimuka, Oscar Kisanji) and Tanzania Forest Service (Bw. Relingo), for logistical support and transportation. We thank many village headmen and farmers for access to forest sites within their lands for sampling. Finally, we would like to thank the MBL Stable Isotope laboratory and Dr. Marshall Otter for his expertise with producing and interpreting soil and leaf C, N and stable isotope data. This study was funded in part by NSF PIRE Grant OISE 0968211, a Dissertation Support Grant to Marc Mayes from Brown University (2015–2016), and completed with permission and cooperation from the Tanzania Commission on Science and Technology (COSTECH permits 2013‐261‐NA‐2014‐199 and 2015‐183‐ER‐2014‐199). Data and code for analyses can be accessed at a Github repository: https://github.com/mtm17/MiomboN.git.
    Description: 2019-11-08
    Keywords: Nitrogen ; Africa ; Miombo ; Tropical dry forest ; Carbon ; Secondary forest regrowth
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  • 32
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    Dissolved and sinking particulate organic nitrogen data from a large volume mesocosm experiment in the Noumea Lagoon, New Caledonia, measured from January to February 2013 (2019)
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Details
    Publication Date: 2022-10-31
    Description: Dataset: VAHINE nitrogen
    Description: This dataset includes water column dissolved organic nitrogen (DON) concentration and d15N data, as well as sinking particulate nitrogen d15N (“PNsink d15N”) data. These samples were collected inside triplicate (“M1”, “M2”, and “M3”) large volume (i.e., 2.3 m diameter, 15 m deep) mesocosm experiments deployed in a lagoon off of Noumea, New Caledonia. DON samples were collected at 6 m depth daily by a Teflon pump and PVC tubing. PNsink d15N samples were collected daily by SCUBA divers who removed a screw-top plastic bottle from the bottom of the plastic mesocosm. “Swimmers” were removed from the PNsink d15N samples prior to analysis. These measurements were made as part of project "VAriability of vertical and tropHIc transfer of diazotroph derived N in the south wEst Pacific" (VAHINE) to study the fate of fixed nitrogen in the oceanic pelagic food web and its potential impact on carbon export. The field campaign of VAHINE took place in the South West Pacific (New Caledonia) in January and February of 2013 and involved 16 scientists from France, Israel, Germany and the USA. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/739646
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1537314
    Keywords: Nitrogen ; Stable nitrogen isotopes ; Nitrogen fixation ; D15N budget ; Diazotrophs ; Sinking flux
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    Determination of sediment nutrients in the cage fish culture area (before breeding) of the southern Caspian Sea (Mazandaran coast-Kelarabad) (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: This study was conducted to determine phosphorous and nitrogen species at the surface sediment in the southern Caspian Sea (Mazandaran Coast, Kelarabad). Surface sediments samples were collected at three stations from autumn of 2011 to winter of 2012. All samples were perpared by digesting and extracting processes and then phosphorous and nitrogen species concentrations determined using spectroscopy instrument. Results of this study showed that annual mean of Loosely-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Rese.-P and TP was obtained as 5.06±0.33, 55.11±2.52, 42.38±3.74, 102.52±5.68, 172.91±7.12, 275±9.12, 333.30±28.52 and 608±52 µg/g.dw, respectively. The results also showed that inorganic phophotous was less than organic phophorous during different seasons, however, mean percentage of residue-P containing organic compounds and non-degredable compounds was more than 50 percent. Percentage of Ca-P was higher than 60, whereas Bioava.-P was less than 40 percent. In addition, Fe-P and Loosely-P attained the maximum and minimum values, respectively, among the bioavailable phophorous. The order of different forms of phosphorous were recorded as Org-P〉Ca-P〉FeP〉Al-P〉Loosely-P. Annual mean of NH4/N, NO2/N, NO3/N, TIN, TON and TN were observed as 4.23±0.50, 0.06±0.01, 0.74±0.12, 5.02±0.53, 2.48±0.63 and 7.53±0.51 µg/g.dw, respectively. Annual percentage of TIN was two folds than TON and concentration of NH4/N was also four times than NO3/N. As a conclusion, the results revealed that main causes of Bioava.-P adsorbtion and desorbtion were temperature, Eh and pH. Also, the form of NH4+ /N was of a high percntage because of anaerobic condition in the sediments. According to the high ratios of nitrogen/phosphorous of sediments to nitrogen and phosphorous of bottow water, it finds that released of those from the sediments to water will be happned with high rates. Therefore, it is expected that the establishment of fish farming cages should be carried out with more precautionary approaches which not leads to increased algae bloom.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Phophorous ; Nitrogen ; Surface sediment ; Determination ; Breeding
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 42pp.
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    Macro and micro nutrients of tropical seagrasses, Halophila ovalis, H. spinulosa and Halodule uninervis in Johore, Malaysia (2018)
    Details
    Publication Date: 2021-05-19
    Description: The present study determined and compared contents of macro- (Nitrogen-N, Phosphorus-P, Potassium-K, Calcium-Ca, Magnesium-Mg) and micro- (Zinc-Zn, Iron-Fe, Manganese-Mn, Cupper-Cu) nutrients in four seagrass species big-leaved (BL) Halophila ovalis (R. Br.) Hook. f., small-leaved (SL) H. ovalis (R. Br.) Ascherson, H. spinulosa (R. Br.) Aschers. in Neumayer and Halodule uninervis (Forssk.) Aschers from three locations Merambong shoal, Seluyong shoal-1 and Seluyong shoal-2, Johore, Malaysia on March 2013. Dried seagrass samples were subjected to wet digestion method and concentration determined using a Perkin Elmer 5100 PC atomic absorption spectrophotometer. Macro and micro-nutrients varied with species and locations. Observed macro-nutrient contents were high for N (17320 mg kg-1) in big-leaved (BL) H. ovalis from Seluyong shoal-2, P (2921.33 mg kg-1) in big-leaved (BL) H. ovalis from Seluyong shoal-1, and for K (10942.67 mg kg-1) in H. uninervis from Merambong shoal and for Ca (10576 mg kg-1) in small-leaved (SL) H. ovalis from Merambong shoal. Mg (3534.67 mg kg-1) was comparatively higher in H. spinulosa from Merambong shoal. Micro-nutrients such as Zn ranged from 138.67 mg kg-1 to 212 mg kg-1 and Cu from 13.33 mg kg-1 to17.33 mg kg-1 with no discernible differences between species. Fe concentration was consistently higher in all species. Hierarchically macro and micro-nutrients contents did not show a consistent ordered pattern according to species and location. Based on biplots generated by Principle component analysis (PCA), there were clear separation of seagrass species based on the micro- and macro-nutrient contents with locations from Malaysia and other regions.
    Description: Published
    Keywords: Biotechnology ; Halodule sp ; Halophila sp ; Macro-nutrient ; Micro-nutrient ; PCA ; Nitrogen ; Phosphorus ; Potassium ; Calcium ; Magnesium ; Zinc ; Iron ; Manganese ; Cupper
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.246-261
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  • 35
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    Epidemiological study on some environmental and management parameters affecting on WSD occurrence in Fenneropenaeus indicus and Penaeus vannamei (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: For the first time white spot disease (WSD) was reported in shrimp farms of khoozestan province, in southwest of IRAN in 2002. Then in 2005 the neighbor province, boushehr, was contaminated. In 2008 WSD outbreak reported in sistan-bloochestan province in southeast of Iran. In 2015 all of southern shrimp farms of country except Hormozgan, the middle southern province, which has remained free of WSD, are being contaminated. White Spot disease suspended shrimp culture in thousands hectares of shrimp farms. Considering that white spot disease has not been observed in Hormozgan province yet, the question is; to what extent environmental and management factors participated in preventing WSD outbreak or cause WSD outbreak. In this study (20102012), the effects of environmental factors and management, stressors that decrease immune system function of shrimp are discussed. In addition, the role of pathogen as the main factor of outbreak is discussed. The goal of this study is to define environmental parameters and management practices associates with outbreak of white spot disease in affected provinces and discover reasons of being Hormozgan province free of this disease. In this study the role of the local environmental factors and management practice stressors in susceptibility to WSD was determine. Both the effects of environmental factors in water of ponds including total ammonia, nitrogen, dissolved oxygen, pH, salinity, transparency, and temperature and management issues related to biosecurity are studied. There were overlaps on physical and chemical parameter values obtained in clear areas with contaminated areas .Results of the data analysis suggest that lack of association with WSD incidence was 7 times greater than WSD incidence despite of disease outbreak in sistan-bloochestan province, so other sources of white spot disease virus incidence was suspected in affected areas. Histopathological examinations and polymerase chain reaction (PCR) tests during project performance did not reveal white spot disease virus evidences in post larvae examined from khoozestan province stocked in farms but disease outbreak was happened in that farms , so we suspected to management practice include feed , pond preparation and carrier of disease . Recorded values of temperature and salinity in some months during inspection in Hormozgan province specified stressful condition that may lead to WSD outbreak, however the disease did not appear. Therefore the hypothesis that the water physical and chemical conditions are reasons to prevent disease outbreak in Hormozgan province is being rejected. The policy of Hormozgan’s fishery authorities, to replaced Fenneropenaeus indicus with specific pathogen free Litopenaeus vannamei, that is more resistant to some of diseases, before incidence of WSD in farms and to before being endemic in the Hormozgan province, made an advantage compare to affected southern provinces that introduced Litopenaeus vannamei after WSD prevalence to their farms. However it does not guarantee to maintain current trend of being Hormozgan province farms free of white spot disease. Therefore establishing the principals of biosecurity are strongly emphasized. Strategies taken by the proficient authorities in preparation of SPF shrimp broodstock can be the most important factor in preventing WSD. Regarding biosecurity principals purchased feed must be free of shrimp head powder. Construction the new shrimp farms should be as far as it could be away from contaminated areas.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Environmental ; Physical ; Chemical ; Epidemiological study ; WSD ; Fenneropenaeus indicus ; Penaeus vannamei ; Shrimp ; White Spot Disease ; Temperature ; Salinity ; PCR ; Polymerase Chain Reaction ; Ammonia ; Nitrogen ; Dissolved oxygen ; pH ; Transparency
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 468pp.
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    Improvement the texture properties and acceptability of Silver Carp Investigation on possibility of burger by addition pectin in the fish burger material (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: In this study the physical properties of silver carp burger over a period of six months at a temperature of -18 ċ were studied using pectin. Indicators such as hardness texture,juiciness, flavor and overall acceptance of the product containing. The product were evaluated using qualified assessors، the microbial,chemical markers to evaluate the qualitative change such as peroxide treatments, total volatile nitrogen bases ، total count of bacteria and examined psychotropic of tests six months of treatments carried out on a monthly basis. The results indicate that the addition of pectin 0/3 percent of total admissions acceptance of burgers tissue was obtained and significant differences are. The chemical test results were also increased with storage time burger in refrigerators -18 degrees. Range of volatile nitrogen bases out of 15.2±1.2 at the time of 26/5±1.17 mg/100, the peroxide from 0.6±0.61 to 3/56±0.6 meq/kg of oxygen was. Thus despite a significant increase in indicators of physical Chemical and sensory evaluation of texture analysis. In the past six months storage period of -18 degrees, burger productive uses of pectin 0/3 percent of the limit between acceptable and will was.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Physical ; Microbial ; Chemical ; Burgers ; Fish ; Silver Carp ; Storage ; Quality ; Changes ; The shelf life ; Texture ; Pectin ; Nitrogen ; Bacterial ; Psychotropic
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 42pp.
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  • 37
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    Study of water's physico-chemical Characteristics in the southern Caspian Sea (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: This study was conducted to determine the physico-chemical characteristics of water during four season and 8 transects (Astara, Anzali, Sefidroud, Tonekabon, Nowhshar, Babolsar, Amirabad, Bandar Tourkman) in the Southern of Caspian Sea in 2009-2010. 480 samples were collected at different water layers and then physicochemical parameters were measured based on standard methods. Result of this study showed that surface water temperature was varied from 7.2 to 29.8 ◦C in winter and summer, respectively. Minimum fluctuation of water temperature was observed at 100 m depth (6.8-10.3 ◦C). Mean value of water transparency was obtained 4.91±0.24 m. This value increased from inshore to offshore. pH value was fluctuated from 7.15 to 8.83 unit with variance of 1.54. Maximum DO concentration was observed at surface layer (8.40±0.08 mg/l) with 137±18 saturation and minimum was at 100 m depth (6.46±0.18) with 86.1±2.8 saturation. The nitrite, nitrate and ammonium concentration were ranged 0.0-0.2, 0.0-4.6 and 0.05-7.12 µM, respectively. Maximum value of TN was observed at inshore and minimum at offshore (100m). Nitrite concentration decreased from inshore to offshore but increased from surface to the bottom (100 m). The inorganic phosphorous increased at surface water and also at the bottom. Trend of inorganic and TP was similar. Minimum of N/P ratio were observed at summer (5.48±0.38) and maximum value at winter (9.13±0.46). This value of N/P ratio showed that the growth of phytoplankton was limited by nitrogen. The dissolved silicate was decreased from spring (230.7±6.65 µg/l) to winter.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Water ; Physico-chemical parameters ; Temperature ; pH ; Phosphorous ; Phytoplankton ; Nitrogen ; Dissolved silicate ; Fluctuation
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 79pp.
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  • 38
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    Investigating the influence of different concentrations of sodium nitrate and sodium bicarbonate ingredients on biomass and lipids production on microalgae (Neochloris oleoabundans) (2018)
    Details
    Publication Date: 2021-05-19
    Description: Carbon and nitrogen sources are considering as the essential substances for microalgae growth. In this study the effects of sodium Nitrate (NaNO3) and sodium bicarbonate (NaHCO3) on the growth rate of N. oleoabundans microalgae in BBM culture medium were investigated. In this regards, different concentrations of NaNO3 as 0, 0.5. 1.0, 2.5, 5 and 10 and NaHCO3 as 0, 0.25, 0.5, 0.75, 1.0 and 1.25 in BBM during 21 days were tested. According to the results, by application of 10 mM NaNO3 the highest number of microalgae as (84.66±0.577)× 106 cells/mL was recorded and in case of nitrogen absence no increase in cell numbers was observed (p 〈0.05). However, by increasing of the concentration of NaNO3, the lipid production was decreased which the highest amount of lipid was recorded as 1.32±0.27 gL-1 without nitrogen addition (p 〈0.05). In case of NaHCO3, by addition of 1.25 gL-1 sodium bicarbonate the highest cell number as (96±1.00)× 106 cell/mL was recorded whereas in its absence the lowest number of (2.00±0.00)× 106 cell/mL was obtained (p 〈0.05). Similarly, by addition of higher amounts of NaHCo3, the lipid production was decreased as its highest amount as 0.3±0.144 gL-1 was produced at level of 0.25 gL-1 of NaHCO3 (p 〈0.05). Considering the positive effects of NaHCO3 on growth of N. oleoabundans on BBM, it is recommended to use it for mass production of this microalgae.
    Description: Published
    Keywords: N. oleoabudnans microalgae ; Biomass ; Sodium nitrate ; Sodium bicarbonate ; BBM ; Neochloris oleoabundans ; Carbon ; Nitrogen
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.71-79
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  • 39
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    Ecological study on the Persian Gulf Martyres Lake, Tehran (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: The ecological study of the Persian Gulf Martyres Lake carried out at the 5 stations between 2013 and 2014. This study identified 35 phytoplankton taxa. The diatoms taxa was dominated and their abundance recorded highest (2000 000 cell. l-1) in the lake. The annual phytoplankton abundance was measured as 2500 000 cell. l-1 during the study. The total nitrogen and water temperature were the significant a biotic parameters to increase cyanophytes abundance. Furthermore, 37 zooplankton taxa were identified. The Rotatoria abundance was dominated zooplankton. The annual zooplankton abundance was measured as 72 ind.l-1. Based on the CCA, there was no correlation between Rotatoria abundance and a biotic parameters. The study benthos showed Ephemeroptera and Diptera abundance were dominated; artificial bottom and lack of sediment and organic matters were the main reasons in decreasing of the benthos density. The Chitgar lake is the poorest lake in Iran due to low density of plankton and benthos organisms. The estimation of fish production was 123 kg/ha and for the lake was determaind 16 tonne. The finding display, invasive species was the main fish Chitgar lake that would be negative effect and increase eutriphication trend in the lake. Phosphorus parameter was limited parameters and trophy level recorded low due to high N/P ration in the lake. In overall the Chitgar lake situation is in Oligotrophic category with the low trophy level.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Ecological ; Phytoplankton ; Zooplankton ; Benthose ; Trophy ; Abundance ; Nitrogen ; Temperature
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 92pp.
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  • 40
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    Determination of nutrients, BOD and COD in manured polyculture ponds (2018)
    Details
    Publication Date: 2021-05-19
    Description: In experimental ponds total ammonia solution, total nitrogen, phosphate and inorganic carbon varied between 0-1050), 178-1093, phosphate 0-88 and 130-5410 ug/lit) respectively. During the growing season the total amount of nitrogen (N), phosphate (P) and carbon (C) were fluctuating between (0.7-1.9), (0.062-2.05), (49.71-130) mg/gr. The primary variation range was 0.98 and 8.9 carbon/m2 per day, COD was 11-109 and BOD was 0.4-16.35 mg/lit oxygen. The results showed that in spite of using inorganic manures 100-150 kg/ha per day, the ponds still had the ability of digestion of inorganic carbon, nitrogen and phosphorus. In the majority of the ponds the rate of total sediment of inorganic C and P were increased during growing period. We can use also COD and BOD as the manuring rate indicator in fish pond ecosystems.
    Description: Published
    Keywords: Nutrients ; BOD ; COD ; Polyculture ; Ponds ; Ammonia ; Nitrogen ; Phosphate ; Inorganic ; Carbon ; Sediment ; Growing ; Manuring rate ; Fish ; Ecosystems
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.1-22
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  • 41
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    The study of the Nitrogen and Phosphorus concentration and some of the physicochemical parameters change in karkheh Reservior and determining of budget (2018)
    Iranian Fisheries Science Research Institute | Ahvaz, Iran
    Details
    Publication Date: 2021-05-19
    Description: This project was conducted to survey the changes of Nitrogen and Phosphorous in Karkheh reservoir and determine it's budget with the support of south Iranian Fisheries Research Center from January 2002 to December 2003. ....
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: river ; Nitrogen ; Environmental parameters ; Nutrients
    Repository Name: AquaDocs
    Type: Report , Not Known
    Format: 150pp.
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  • 42
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    Impact of seabed resuspension on oxygen and nitrogen dynamics in the northern Gulf of Mexico : a numerical modeling study (2018)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 123 (2018): 7237-7263, doi:10.1029/2018JC013950.
    Description: Resuspension affects water quality in coastal environments by entraining seabed organic matter into the water column, which can increase remineralization, alter seabed fluxes, decrease water clarity, and affect oxygen and nutrient dynamics. Nearly all numerical models of water column biogeochemistry, however, simplify seabed and bottom boundary layer processes and neglect resuspension. Here we implemented HydroBioSed, a coupled hydrodynamic‐sediment transport‐biogeochemical model to examine the role of resuspension in regulating oxygen and nitrogen dynamics on timescales of a day to a month. The model was implemented for the northern Gulf of Mexico, where the extent of summertime hypoxia is sensitive to seabed and bottom boundary layer processes. Results indicated that particulate organic matter remineralization in the bottom water column increased by an order of magnitude during resuspension events. This increased sediment oxygen consumption and ammonium production, which were defined as the sum of seabed fluxes of oxygen and ammonium, plus oxygen consumption and ammonium production in the water column due to resuspended organic matter. The increases in remineralization impacted biogeochemical dynamics to a greater extent than resuspension‐induced seabed fluxes and oxidation of reduced chemical species. The effect of resuspension on bottom water biogeochemistry increased with particulate organic matter availability, which was modulated by sediment transport patterns. Overall, when averaged over the shelf and on timescales of a month in the numerical model, cycles of erosion and deposition accounted for about two thirds of sediment oxygen consumption and almost all of the sediment ammonium production.
    Description: DOC | National Oceanic and Atmospheric Administration (NOAA); U.S. National Oceanic and Atmospheric Administration's National Centers for Coastal Ocean Science Center for Sponsored Coastal Ocean Research Grant Numbers: NA09NOS4780231, NA09NOS4780229
    Keywords: Regional Ocean Modeling System (ROMS) ; Northern Gulf of Mexico continental shelf hypoxia ; Sediment transport and resuspension ; Particulate organic carbon (POC) ; Nitrogen ; Oxygen
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 43
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    Nitrogen limitation of the summer phytoplankton and heterotrophic prokaryote communities in the Chukchi Sea (2018)
    Frontiers Media
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Marine Science 5 (2018): 362, doi:10.3389/fmars.2018.00362.
    Description: Major changes to Arctic marine ecosystems have resulted in longer growing seasons with increased phytoplankton production over larger areas. In the Chukchi Sea, the high productivity fuels intense benthic denitrification creating a nitrogen (N) deficit that is transported through the Arctic to the Atlantic Ocean, where it likely fuels N fixation. Given the rapid pace of environmental change and the potentially globally significant N deficit, we conducted experiments aimed at understanding phytoplankton and microbial N utilization in the Chukchi Sea. Ship-board experiments tested the effect of nitrate (NO3-) additions on both phytoplankton and heterotrophic prokaryote abundance, community composition, photophysiology, carbon fixation and NO3- uptake rates. Results support the critical role of NO3- in limiting summer phytoplankton communities to small cells with low production rates. NO3- additions increased particulate concentrations, abundance of large diatoms, and rates of carbon fixation and NO3- uptake by cells 〉1 μm. Increases in the quantum yield and electron turnover rate of photosystem II in +NO3- treatments suggested that phytoplankton in the ambient dissolved N environment were N starved and unable to build new, or repair damaged, reaction centers. While some increases in heterotrophic prokaryote abundance and production were noted with NO3- amendments, phytoplankton competition or grazers likely dampened these responses. Trends toward a warmer more stratified Chukchi Sea will likely enhance summer oligotrophic conditions and further N starve Chukchi Sea phytoplankton communities.
    Description: Fieldwork and analysis for the ICESCAPE program was supported by Ocean Biology and Biogeochemistry Program of the National Aeronautic and Space Administration under Grant No. NNX10AF42G to KA.
    Keywords: Phytoplankton ; Nitrogen ; Chukchi Sea ; Nitrate ; Nutrient limitation
    Repository Name: Woods Hole Open Access Server
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  • 44
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    The effects of slurry on Larviculture of Rutilus firisii kutum and chienes carp yield and determination of efficient concentration for increasing of production (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: Rutilus frisii kutum is one of the important fish of Caspian Sea which has significant economical role in the region .The objective of this project is a comparative study on traditional culture of fishes versus slurry. This survey were conducted on nine pound of 1.7 hec triplicate with their treatment with stocking densities of 1.7 million fish larva at Dr yousefpoor center (Affiliated of Shahid Beheshti culture and propagation) at Siakal village , 32 km far from Rasht city in North of Iran, the first treatment considered as control which practice traditionally (using concentrated food plus grinded kilka fish) .In the second treatment for 13 days the pound supplied only by slurry then followed by concentrated fish food only .The tired treatment started with slurry for 13 days and followed by slurry plus concentrated food. The physical and chemical parameters of water, plankton, biometry of fish, growth indices such as daily weight growth (DWG), daily length growth (DLG) as well as specific ratio (SGR) were monitored weekly. The result indicate that net fish production was 1.7 to 2 times higher in slurry than traditional treatment also the survival rate were 1.7 times higher in slurry treatment . The treatment of slurry follow by addition of concentrated food plus slurry showed higher yield camper to others. Slurry with several active substances is more effective and can promote the growth of zooplanktons which is the food of larval stage of rutilus frisi kutum. In second phase of this project the effect of slurry was surveyed on Chinese carp. This experiment was conducted in triplicate with two treatment ( one treatment is control which use cow manure plus chemical fertilizer and second treatment was conducted with slurry ) and stocked with 2375 N/hec ( Silver carp 60% , Big head 15%, common carp 17% and grass carp 8%) at June. In this survey common carp and grass carp were feed with concentrate food and fresh grasses respectively. Chemical factors were measured once for each two week and density of plankton was determined when it was necessarily. Nutritional content of phosphorous, nitrogen, calcium, potassium and magnesium after anaerobic fermentation as well as protein and lipid content with 1.4and 1.9 times respectively were higher in slurry treatment than control. The results showed that survival rate and yield were higher in slurry than control. The increasing percent of yield were 13.5, 2.6, 18.4 and 85.3 in Silver carp, Big head, common carp and grass carp respectively. The survival rate of grass carp was twice higher in slurry treatment than control. Zooplankton abundant in slurry pounds was more but blue- green algae density was less than control. Protein and lipid analysis reviled no significant difference between control and slurry. In general the result indicate that the slurry with higher nutritional content is more effective on the survival and growth rate of fishes and also is more efficient in proliferation of plankton in particular zooplankton.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Economical ; Chemical ; Nutritional ; Slurry ; Rutilus frisii kutum ; Cow fertilize ; Larviculture ; Carp ; Culture ; Plankton ; SGR ; Zooplanktons ; Silver Carp ; Big head carp ; Common carp ; Grass carp ; Phosphorous ; Nitrogen ; Survival rate ; Protein ; Lipid
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 158pp.
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  • 45
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    Monitoring on nutrients of sediment with emphasis on algal bloom event in the southern of Caspian Sea (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: This study was conducted to spatio-temporal fluctuation and distribution of phosphorous and nitrogen species, total organic carbone and some environmental parameters at suface sediments in the southern of Caspian Sea. In current study, 48 samples were collected from four stations (Bandar Anzali, Tonekabon, Bandar Nowshahr and Bandar Amirabad) and three dephths (5, 10 and 20 meter) during four seasons in 2013-2014. Results of this study showed that annual mean of Adsorbed-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Rese.-P and TP were obtained 6.68±0.63, 60.90±2.44, 24.94±2.39, 94.52±3.62, 1868±36, 1963±37, 87.51±9.52 and 2050±38 µg/g.dw, respectively. Result also showed that inorganic phophotous was maximum during different seasons, however, percent mean of residue-P which containe organic compounds and non-degrediable compounds, was less that 5 percent. Percent of Ca-P was higher than 90, whereas Bioava.-P was less that 10 percent. The order of different forms of phosphorous were registered Ca-P〉Org-P〉Fe-P〉Al-P〉Adsorbed-P.Annual mean of NH4/N, NO3/N, TIN, TON and TN were observed 2.56±0.27, 0.89±0.12, 3.52±0.26, 6.06±0.27 and 9.57±0.32µg/g.dw respectively. Annual percent of TON was two folds than TIN and NH4/N was also three times than NO3/N. In addition, mean of Fe, Al, Ca, Eh and TOC% were obtained 25.39±0.65, 18.76±0.68, 60.15±1.50 mg/g.dw and 67.02±0.68, 1.11±0.09, respectively. Maximum mean of carbon (1152±171), nitrogen (0.87±0.05) and phoporous (74±23) µM/g were observed in fall, winter and summer, recpectively. Also, maximum ratios of TOC:TP (16.8±2.3) and TOC:TN (2378±363) were obtained in fall season. As a conclusion, mian role of Adsorbed-P, Fe-P and Al-P adsorbed and desorbed were temperature, Eh and pH, respectively. Results of this study showed that TOC:TN was very high which represented to excitance of organic matter with almost non-degrediable. Whereas, TOC:TP was low which showed that organic phophoros was not related to proteins and phospholipids therefore sources of org-P were belong to other compounds.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Phophorous ; Carbon ; Nitrogen ; Environmental parameters ; Surface sediments ; Nutrients ; Algal bloom ; Species ; Samples ; Temperature ; pH ; Proteins ; Phospholipid
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 82pp.
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  • 46
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    Water quality determination in Khuzestan creeks, northwest of Persian Gulf using WQS Index (2018)
    Details
    Publication Date: 2021-05-19
    Description: Water quality was studied in Mahshahr creeks from 2005-2006. Due to special characteristics of Mahshahr creeks, high fisheries potential and sever exploitation and human pressure, WQS index was selected for determination of ecological health status of the area. Eight creeks Ghannam, Zasngy, Doragh,Ahmady, Darvish, Patil, Ghazaleh and Bihad were selected and monthly sampling of physical and chemical parameters was done by bottle sampler. Six primary water quality parameters were used to develop an integrated measure of overall water quality. The parameters included Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD sub(5)), Total nitrogen (TN), Total phosphorus (TP), pH and Ammonia (NH3). The results of two ways ANOVA showed that differences were significant only for nitrite between seasons and for pH, ammonium, nitrite and total phosphorus between creeks. Based on index description, parameters pH, NH3 and DO were placed in grade five indicating good quality for water. Total nitrogen was in grade three indicating poor quality and BOD5 and total phosphor were in grade one showing bad quality for water. According to the index, high similarity was found in studied creeks and the total value was found to be 3.33 for the whole studied area, indicating poor water quality.
    Description: Published
    Keywords: Biochemical oxygen demand ; Brackish ; Phosphorus ; Water quality ; pH ; Nitrogen
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.65-72
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  • 47
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    Water column nitrate+nitrite d15N measurements from R/V L'Atalante in the southwest Pacific Ocean between New Caledonia and Tahiti from February to March 2015 (2018)
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Details
    Publication Date: 2022-10-31
    Description: Dataset: OUTPACE - water column nitrate+nitrite
    Description: Constraining the rates and spatial distribution of di-nitrogen (N2) fixation fluxes to the ocean informs our understanding of the environmental sensitivities of N2 fixation as well as the timescale over which the fluxes of nitrogen (N) to and from the ocean may respond to each other. Here we quantify rates of N2 fixation as well as its contribution to export production along a zonal transect in the Western Tropical South Pacific (WTSP) Ocean using N isotope (“d15N”) budgets. Comparing measurements of water column nitrate+nitrite d15N with the d15N of sinking particulate N at a western, central, and eastern station, these d15N budgets indicate high, modest, and low rates of N2 fixation at the respective stations. The results also imply that N2 fixation supports exceptionally high, i.e., >50%, of export production at the western and central stations, which are also proximal to the largest iron sources. These geochemically-based rates of N2 fixation are equal to or greater than those previously reported in the tropical North Atlantic, indicating that the WTSP Ocean has the capacity to support globally significant rates of N2 fixation, which may compensate for N removal in the oxygen deficient zones of the eastern tropical Pacific. For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/733237
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1537314
    Keywords: Nitrogen ; Nitrate d15N ; D15N budget ; Southwest Pacific ; Nitrogen fixation
    Repository Name: Woods Hole Open Access Server
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  • 48
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    Slowed biogeochemical cycling in sub-arctic birch forest linked to reduced mycorrhizal growth and community change after a defoliation event (2017)
    Springer
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosystems 20 (2017): 316–330, doi:10.1007/s10021-016-0026-7.
    Description: Sub-arctic birch forests (Betula pubescens Ehrh. ssp. czerepanovii) periodically suffer large-scale defoliation events caused by the caterpillars of the geometrid moths Epirrita autumnata and Operophtera brumata. Despite their obvious influence on ecosystem primary productivity, little is known about how the associated reduction in belowground C allocation affects soil processes. We quantified the soil response following a natural defoliation event in sub-arctic Sweden by measuring soil respiration, nitrogen availability and ectomycorrhizal fungi (EMF) hyphal production and root tip community composition. There was a reduction in soil respiration and an accumulation of soil inorganic N in defoliated plots, symptomatic of a slowdown of soil processes. This coincided with a reduction of EMF hyphal production and a shift in the EMF community to lower autotrophic C-demanding lineages (for example, /russula-lactarius). We show that microbial and nutrient cycling processes shift to a slower, less C-demanding state in response to canopy defoliation. We speculate that, amongst other factors, a reduction in the potential of EMF biomass to immobilise excess mineral nitrogen resulted in its build-up in the soil. These defoliation events are becoming more geographically widespread with climate warming, and could result in a fundamental shift in sub-arctic ecosystem processes and properties. EMF fungi may be important in mediating the response of soil cycles to defoliation and their role merits further investigation.
    Description: This work was supported by NERC (UK Natural Environment Research Council) research Studentship training grant NE/J500434/1.
    Keywords: Defoliation ; Nitrogen ; Carbon ; Birch forest ; Sub-arctic ; Ectomycorrhizal fungi ; Community change
    Repository Name: Woods Hole Open Access Server
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  • 49
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    Nitrogen fixation rates from samples collected in the Chukchi Sea, Arctic Ocean near Barrow, Alaska in August of 2011 (ArcticNITRO project) (2017)
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Details
    Publication Date: 2022-10-31
    Description: Dataset: Arctic Nitrogen Fixation Rates
    Description: This dataset provides rates of nitrogen fixation for the coastal Chukchi Sea near Barrow, Alaska. Nitrogen fixation supplies ‘new’ nitrogen to the global ocean and supports primary production and impacts global biogeochemical cycles. Historically, nitrogen fixation in marine waters was considered a predominantly warm water process but this and other recent studies have shown that nitrogen fixation is occurring at low rates in polar waters. This dataset reports rates of 3.5 – 17.2 nmol N L-1 d-1 in the ice-free coastal Alaskan Arctic. Additional investigations of high-latitude marine diazotrophic physiology are required to refine these N2 fixation estimates. For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/701789
    Description: NSF Arctic Sciences (NSF ARC) PLR-0909839
    Keywords: Nitrogen fixation ; Temperature ; Arctic Ocean ; Nitrogen ; Nutrients ; Chukchi Sea
    Repository Name: Woods Hole Open Access Server
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  • 50
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    Geochemical controls on the distribution and composition of biogenic and sedimentary carbon (2017)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2017
    Description: Organic carbon (OC) preserved in marine sediments acts as a reduced carbon sink that balances the global carbon cycle. Understanding the biogeochemical mechanisms underpinning the balance between OC preservation and degradation is thus critical both to quantifying this carbon reservoir and to estimating the extent of life in the deep subsurface biosphere. This work utilizes bulk and spatially-resolved X-ray absorption spectroscopy to characterize the OC content and composition of various environmental systems in order to identify the role of minerals and surrounding geochemistry in organic carbon preservation in sediments. Biogenic manganese (Mn) oxides formed either in pure cultures of Mn-oxidizing microorganisms, in incubations of brackish estuarine waters, or as ferromanganese deposits in karstic cave systems rapidly associate with OC following precipitation. This association is stable despite Mn oxide structural ripening, suggesting that mineral-associated OC could persist during early diagenetic reactions. OC associated with bacteriogenic Mn oxides is primarily proteinaceous, including intact proteins involved in Mn oxidation and likely oxide nucleation and aggregation. Pelagic sediments from 16 sites underlying the South Pacific and North Atlantic gyres and spanning a gradient of sediment age and redox state were analyzed in order to contrast the roles of oxygen exposure, OC recalcitrance, and mineral-based protection of OC as preservation mechanisms. OC and nitrogen concentrations measured at these sites are among the lowest globally (〈0.1%) and, to a first order, scale with sediment oxygenation. In the deep subsurface, however, molecular recalcitrance becomes more important than oxygen exposure time in protecting OC against remineralization. Deep OC consists of primarily amide and carboxylic carbon in a scaffolding of aliphatic and O-alkyl moieties, corroborating the extremely low C/N values observed. These findings suggest that microbes in oxic pelagic sediments are carbon-limited and may preferentially remove carbon relative to nitrogen from the organic matter pool. As a whole, this work documents how interactions with mineral surfaces and exposure to oxygen generate a reservoir of OC stabilized in sediments on at least 25-million year time scales.
    Description: This research was supported by the NSF graduate research fellowship 1122374, NSF EAR- 82279000, NASA Exobiology grant NNX15AM04G, WHOI Coastal Ocean Institute and Ocean Ventures Fund grants, the NSF Center for Dark Energy Biosphere Investigations (C-DEBI, OCE-0939564) graduate fellowship, and C-DEBI research grant CH20655.
    Keywords: Biosphere ; Nitrogen ; Microorganisms ; Knorr (Ship : 1970-) Cruise KN223
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
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    Fluid-induced breakdown of white mica controls nitrogen transfer during fluid–rock interaction in subduction zones (2017)
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of Taylor & Francis for personal use, not for redistribution. The definitive version was published in International Geology Review 59 (2017): 702-720, doi:10.1080/00206814.2016.1233834.
    Description: In order to determine the effects of fluid–rock interaction on nitrogen elemental and isotopic systematics in high-pressure metamorphic rocks, we investigated three different profiles representing three distinct scenarios of metasomatic overprinting. A profile from the Chinese Tianshan (ultra)high-pressure–low-temperature metamorphic belt represents a prograde, fluid-induced blueschist–eclogite transformation. This profile shows a systematic decrease in N concentrations from the host blueschist (~26 μg/g) via a blueschist–eclogite transition zone (19–23 μg/g) and an eclogitic selvage (12–16 μg/g) towards the former fluid pathway. Eclogites and blueschists show only a small variation in δ15Nair (+2.1 ± 0.3‰), but the systematic trend with distance is consistent with a batch devolatilization process. A second profile from the Tianshan represents a retrograde eclogite–blueschist transition. It shows increasing, but more scattered, N concentrations from the eclogite towards the blueschist and an unsystematic variation in δ15N values (δ15N = + 1.0 to +5.4‰). A third profile from the high-P/T metamorphic basement complex of the Southern Armorican Massif (Vendée, France) comprises a sequence from an eclogite lens via retrogressed eclogite and amphibolite into metasedimentary country rock gneisses. Metasedimentary gneisses have high N contents (14–52 μg/g) and positive δ15N values (+2.9 to +5.8‰), and N concentrations become lower away from the contact with 11–24 μg/g for the amphibolites, 10–14 μg/g for the retrogressed eclogite, and 2.1–3.6 μg/g for the pristine eclogite, which also has the lightest N isotopic compositions (δ15N = + 2.1 to +3.6‰). Overall, geochemical correlations demonstrate that phengitic white mica is the major host of N in metamorphosed mafic rocks. During fluid-induced metamorphic overprint, both abundances and isotopic composition of N are controlled by the stability and presence of white mica. Phengite breakdown in high-P/T metamorphic rocks can liberate significant amounts of N into the fluid. Due to the sensitivity of the N isotope system to a sedimentary signature, it can be used to trace the extent of N transport during metasomatic processes. The Vendée profile demonstrates that this process occurs over several tens of metres and affects both N concentrations and N isotopic compositions.
    Description: Support of this project was partly provided by National Science Foundation grant EAR-0711355 to GEB.
    Description: 2017-10-10
    Keywords: Nitrogen ; N isotopes ; White mica ; Fluid-rock interaction ; Subduction ; High-pressure metamorphic rocks
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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    Requerimentos ambientais da espécie invasora Hydrilla verticillata em uma planície de inundação tropical. (2017)
    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais.
    Details
    Publication Date: 2022-05-25
    Description: Hydrilla verticillata is a submersed freshwater macrophyte, considered a weed in several countries, where it dislocated indigenous species and compromised multiple uses of continental water bodies. Its presence was recently detected in the upper Paraná River floodplain, where large stands developed in the littoral zone of the main channel of this river. However, it is not found in lentic environments in this floodplain, where limnological characteristics are different from the Paraná River. Submersed macrophytes growth is limited by two main factors: nutrients and underwater light availability. The aim of this study was to assess, through microcosms experiments, H. verticillata growth responses to sediment nitrogen and phosphorus availability (sediment amendment and dose-response experiments), and its photosynthetic rates under different light intensities (light-photosynthesis experiment). Water, plants and sediment were sampled in H. verticillata stands close to Nupélia?s advanced research base in Porto Rico, Paraná, Brazil. Apical shoots were cultivated in different sediment nutrients concentrations for approximately 24 days, and growth rates were related to nutrients availability through variance analyses. Results from sediment amendment experiments indicate that H. verticillata growth in the floodplain is limited by nutrients availability. On the other hand, dose-response experiments did not show significant differences in growth rates with the different concentrations of sediment nutrients. Light-photosynthesis experiments where conducted inside sealed glass bottles, containing H. verticillata apical shoots and filtered water, submitted to different light intensities. Photosynthetic rates were determined in mg O2 g-1 DW h-1. H. verticillata showed effectiveness in light use, presenting low LCP and high k1/2. The results obtained here do not explain, alone, this species distribution in the floodplain, indicating that other factors must be acting in its distribution in this Environmental Protection Area.
    Description: Hydrilla verticillata é uma macrófita submersa considerada invasora em diversos países, deslocando espécies nativas e comprometendo múltiplos usos dos corpos aquáticos. Sua presença foi recentemente detectada na planície de inundação do alto rio Paraná, onde formou grandes bancos na calha principal deste rio. Porém, ela não se desenvolveu em ambientes lênticos da planície, cujas características limnológicas são diferentes daquelas do canal principal do rio. Os dois principais fatores limitantes para o crescimento de plantas submersas enraizadas são disponibilidade de nutrientes e de radiação subaquática. O objetivo deste estudo foi avaliar, em microcosmos, o crescimento de H. verticillata em resposta às concentrações de nitrogênio de fósforo do sedimento (experimentos sedimento natural+adições e dose-resposta), e suas taxas fotossintéticas em resposta a diferentes intensidades luminosas (experimento luz-fotossíntese). Água, plantas e sedimento utilizados foram obtidos em pontos próximos à base avançada de pesquisa do Nupélia, em Porto Rico, Paraná, Brasil. Porções da planta foram cultivadas com diferentes concentrações de nutrientes do sedimento por cerca de 24 dias, e a resposta do seu crescimento foi relacionada ao gradiente de concentrações utilizado através de análises de variância. Os resultados obtidos em sedimento natural+adições indicam que H. verticillata tem seu crescimento limitado na planície estudada pela disponibilidade de nutrientes. Entretanto, o experimento dose-resposta não demonstrou diferenças significativas no crescimento da planta com as diferentes concentrações utilizadas. Os experimentos luz-fotossíntese foram realizados em garrafas de vidro vedadas contendo porções apicais de H. verticillata e água filtrada, submetidas a diferentes intensidades luminosas. As taxas fotossintéticas foram determinadas em mg O2 g-1 MS h-1. Esta espécie demonstrou eficácia na utilização da radiação, apresentando baixo PCL e alto k1/2. Os resultados obtidos não explicam, por si só, a distribuição desta espécie nessa planície, indicando que outros fatores devem estar atuando na distribuição de H. verticillata nesta Área de Proteção Ambiental.
    Description: Masters
    Keywords: Upper Paraná River ; Brazil ; Ciências Ambientais ; Brasil ; Ecophysiology ; Hydrilla verticillata (Hydrocharitaceae) ; Nitrogen ; Sediment ; Phosphorus ; Floodplain ; Light ; Macrófitas aquáticas submersas ; Alto rio Paraná ; Fósforo ; Nitrogênio ; Hydrilla verticillata (Hydrocharitaceae) ; Planície de inundação ; Ecofisiologia ; Luz ; Sedimento ; Aquatic macrophytes
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 32pp.
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    Quantifying the effects of commercial clam aquaculture on C and N cycling : an integrated ecosystem approach (2016)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of Coastal and Estuarine Research Federation for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 39 (2016): 1746–1761, doi: 10.1007/s12237-016-0106-0.
    Description: Increased interest in using bivalve cultivation to mitigate eutrophication requires a comprehensive understanding of the net carbon (C) and nitrogen (N) budgets associated with cultivation on an ecosystem scale. This study quantified C and N processes related to clam (Mercenaria mercenaria) aquaculture in a shallow coastal environment (Cherrystone Inlet, VA) where the industry has rapidly increased. Clam physiological rates were compared with basin-wide ecosystem fluxes including primary production, benthic nutrient regeneration, and respiration. Although clam beds occupy only 3% of the ecosystem’s surface area, clams filtered 7-44% of the system’s volume daily, consumed an annual average of 103% of the phytoplankton production, creating a large flux of particulate C and N to the sediments. Annually, N regenerated and C respired by clam and microbial metabolism in clam beds were ~3-fold and ~1.5-fold higher, respectively, than N and C removed through harvest. Due to the short water residence time, the low watershed load, and the close vicinity of clam beds to the mouth of Cherrystone Inlet, cultivated clams are likely subsidized by phytoplankton from the Chesapeake Bay. Consequently, much of the N released by mineralization associated with clam cultivation is ‘new’ N as it would not be present in the system without bivalve facilitation. Macroalgae that are fueled by the enhanced N regeneration from clams represents a eutrophying process resulting from aquaculture. This synthesis demonstrates the importance of considering impacts of bivalve aquaculture in an ecosystem context especially relative to the potential of bivalves to remove nutrients and enhance C sinks.
    Description: This work was supported by Virginia Sea Grant (NA10OAR4170085, #R/71515W, #R/715168), the NSF GK12 Fellowship (DGE-0840804), the Strategic Environmental Research and Development Program – Defense Coastal/Estuarine Research Program Project SI-1413, and NSF Virginia Coast Reserve LTER Project (DEB 0080381, DEB 0621014).
    Description: 2017-05-19
    Keywords: Clam ; Aquaculture ; Nitrogen ; Carbon ; Bivalve ; Ecosystem budget
    Repository Name: Woods Hole Open Access Server
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    Climate change decreases nitrogen pools and mineralization rates in northern hardwood forests (2016)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosphere 7 (2016): e01251, doi:10.1002/ecs2.1251.
    Description: Nitrogen (N) supply often limits the productivity of temperate forests and is regulated by a complex mix of biological and climatic drivers. In excess, N is linked to a variety of soil, water, and air pollution issues. Here, we use results from an elevation gradient study and historical data from the long-term Hubbard Brook Ecosystem Study (New Hampshire, USA) to examine relationships between changes in climate, especially during winter, and N supply to northern hardwood forest ecosystems. Low elevation plots with less snow, more soil freezing, and more freeze/thaw cycles supported lower rates of N mineralization than high elevation plots, despite having higher soil temperatures and no consistent differences in soil moisture during the growing season. These results are consistent with historical analyses showing decreases in rates of soil N mineralization and inorganic N concentrations since 1973 that are correlated with long-term increases in mean annual temperature, decreases in annual snow accumulation, and a increases in the number of winter thawing degree days. This evidence suggests that changing climate may be driving decreases in the availability of a key nutrient in northern hardwood forests, which could decrease ecosystem production but have positive effects on environmental consequences of excess N.
    Description: U.S. National Science Foundation; Andrew W. Mellon Foundation; Spanish Ministry of Education; Portuguese Ministry of Education and Science Grant Number: SFRH/BDP/87966/2012
    Keywords: Carbon ; Global change ; Microbial activity mineralization ; Nitrification ; Nitrogen ; Soil frost
    Repository Name: Woods Hole Open Access Server
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    Particulate organic carbon and nitrogen export from major Arctic rivers (2016)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 30 (2016): 629–643, doi:10.1002/2015GB005351.
    Description: Northern rivers connect a land area of approximately 20.5 million km2 to the Arctic Ocean and surrounding seas. These rivers account for ~10% of global river discharge and transport massive quantities of dissolved and particulate materials that reflect watershed sources and impact biogeochemical cycling in the ocean. In this paper, multiyear data sets from a coordinated sampling program are used to characterize particulate organic carbon (POC) and particulate nitrogen (PN) export from the six largest rivers within the pan-Arctic watershed (Yenisey, Lena, Ob', Mackenzie, Yukon, Kolyma). Together, these rivers export an average of 3055 × 109 g of POC and 368 × 109 g of PN each year. Scaled up to the pan-Arctic watershed as a whole, fluvial export estimates increase to 5767 × 109 g and 695 × 109 g of POC and PN per year, respectively. POC export is substantially lower than dissolved organic carbon export by these rivers, whereas PN export is roughly equal to dissolved nitrogen export. Seasonal patterns in concentrations and source/composition indicators (C:N, δ13C, Δ14C, δ15N) are broadly similar among rivers, but distinct regional differences are also evident. For example, average radiocarbon ages of POC range from ~2000 (Ob') to ~5500 (Mackenzie) years before present. Rapid changes within the Arctic system as a consequence of global warming make it challenging to establish a contemporary baseline of fluvial export, but the results presented in this paper capture variability and quantify average conditions for nearly a decade at the beginning of the 21st century.
    Description: National Science Foundation Grant Numbers: 0229302, 0732985; U.S. Geological Survey; Department of Indian and Northern Affairs
    Description: 2016-11-11
    Keywords: Arctic ; River ; Carbon ; Nitrogen ; Watershed ; Export
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    Seasonal variability of multiple leaf traits captured by leaf spectroscopy at two temperate deciduous forests (2016)
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Remote Sensing of Environment 179 (2016): 1-12, doi:10.1016/j.rse.2016.03.026.
    Description: Understanding the temporal patterns of leaf traits is critical in determining the seasonality and magnitude of terrestrial carbon and water fluxes. However, robust and efficient ways to monitor the temporal dynamics of leaf traits are lacking. Here we assessed the potential of using leaf spectroscopy to predict leaf traits across their entire life cycle, forest sites, and light environments (sunlit vs. shaded) using a weekly sampled dataset across the entire growing season at two temperate deciduous forests. The dataset includes field measured leaf-level directional-hemispherical reflectance/transmittance together with seven important leaf traits [total chlorophyll (chlorophyll a and b), carotenoids, mass-based nitrogen concentration (Nmass), mass-based carbon concentration (Cmass), and leaf mass per area (LMA)]. All leaf properties, including leaf traits and spectra, varied significantly throughout the growing season, and displayed trait-specific temporal patterns. We used a Partial Least Square Regression (PLSR) analysis to estimate leaf traits from spectra, and found a significant capability of PLSR to capture the variability across time, sites, and light environment of all leaf traits investigated (R2=0.6~0.8 for temporal variability; R2=0.3~0.7 for cross-site variability; R2=0.4~0.8 for variability from light environments). We also tested alternative field sampling designs and found that for most leaf traits, biweekly leaf sampling throughout the growing season enabled accurate characterization of the leaf trait seasonal patterns. Increasing the sampling frequency improved in the estimation of Nmass, Cmass and LMA comparing with foliar pigments. Our results, based on the comprehensive analysis of spectra-trait relationships across time, sites and light environments, highlight the capacity and potential limitations to use leaf spectra to estimate leaf traits with strong seasonal variability, as an alternative to time-consuming traditional wet lab approaches.
    Description: This research was supported by the Brown University–Marine Biological Laboratory graduate program in Biological and Environmental Sciences, and Marine Biological Laboratory start-up funding for JT. JT was also partially supported by the U.S. Department of Energy (U.S. DOE) Office of Biological and Environmental Research grant DE-SC0006951 and the National Science Foundation grants DBI-959333 and AGS-1005663. SPS was supported in part by the U.S. DOE contract No. DE-SC00112704 to Brookhaven National Laboratory. JW was supported by the NASA Earth and Space Science Fellowship (NESSF2014).
    Keywords: Phenology ; Leaf physiology ; Foliar chemistry ; Carbon cycle ; Chlorophyll ; Carotenoids ; Nitrogen ; Leaf mass per area ; Partial least square regression (PLSR) ; Sun and shaded leaves
    Repository Name: Woods Hole Open Access Server
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    Lake Victoria: will it support life tomorrow? A case for abatement of pollution and eutrophication of fresh waters. (2015)
    United Nations Environment Programme (UNEP), Pan African START Secretariat (PASS) | Nairobi, Kenya
    Details
    Publication Date: 2021-05-19
    Description: The decline in the quality of water has been associated with human activities in both the catchments and near shore areas. The poor quality of Lake Victoria’s water is a result of discharges of untreated sewer and chemical wastes from urban centres as well as microbacterial and nutrient laden runoffs from pastoral agricultural land, shrub-lands, forests and municipal slums. The deterioration of Lake Victoria’s ecology is linked to the rapid riparian population growth and consequent livelihood activities associated with farming and urbanization. The review demonstrates that the Lake’s water quality has deteriorated to a point that it is no longer able to support aquatic life in the same way it did 40 years ago. The major driving force behind water quality deterioration is population increase. Deforestation, poor agricultural practices, over-stocking and grazing have all contributed to massive soil erosion that continues to convey sediments to the lake. The establishment of institutions that will encourage stakeholder participation in conservation and management of resources at the village, local, national and regional levels is essential for the sustainable utilization of the Lake’s resources. The riparian governments need to show both political will and policy direction through establishing policies that engage the public, and enforce existing rules and regulations that will address the water pollution concerns.
    Description: Published
    Keywords: Freshwater pollution ; Eutrophication ; Sedimentation ; Biochemical oxygen demand ; Nitrogen ; Pesticides ; Heavy metals
    Repository Name: AquaDocs
    Type: Book Section , Not Known
    Format: pp.61-75
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    An Assessment of Nutrient Loading, Eutrophication and Plankton Dynamics in three Marine Tidal Creeks, Kenya: Port Reitz, Mtwapa Creek And Funzi Bay. (2015)
    University of Nairobi
    Details
    Publication Date: 2021-05-19
    Description: Coastal marine eutrophication is recognised as a worldwide problem. On a global scale, it is now estimated that the input of nutrients especially various forms of nitrogen and phosphorus, to marine ecosystems from human sources via rivers are equal to or greater than, the natural input. The proposed study aims at assessing the eutrophication status of creeks to determine effects of nutrient loading on these ecosystems. This aim will be achieved by assessing the forms, concentrations and ratios of nitrogen and phosphorous as principal nutrients and how they affect rates of production and both phytoplankton and zooplankton compositions. The creeks have been chosen due to differences in nutrient loading. Port Reitz and Mtwapa creeks will be compared to Funzi bay, a relative pristine ecosystem. Sampling in these areas will be done taking into consideration, both point and non-point sources of anthropogenic nutrient loading. Physico-chemical parameters that will be analysed at each site include temperature, conductivity, dissolved oxygen and salinity. The various forms and concentrations of Nitrogen and Phosphorous will be analysed using various methods described for the analysis of nutrients in tropical seawater. Various phytoplankton and zooplankton compositions will be counted and analysed statistically using the Shannon-weaver method. The effects of nutrients on primary production, phytoplankton and zooplankton abundance will be determined in a bid to assess eutrophication and nutrient loading effects to productivity of these ecosystems. The information obtained during this study shall contribute significantly to the formulation of pollution/eutrophication control procedures as well as a basis for future research.
    Description: Masters
    Keywords: Nutrients (mineral) ; Eutrophication ; Plankton ; Nitrogen ; Phosphorus ; Primary production ; Marine pollution
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 24pp.
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    Lake Victoria: the Changing Lake. (2015)
    Lake Victoria Environment Management Project (LVEMP) | Kisumu, Kenya
    Details
    Publication Date: 2021-05-19
    Description: Water quality monitoring activities were carried out on physical-chemical parameters, water chemistry and biotic indices at selected littoral and pelagic stations along north-south and east-west transects over an annual cycle between 2000 and 2005. The activities were aimed at collecting baseline information and data for use to define the current lake conditions and make a water quality assessment of the lake in relation to nutrient/ pollutant loadings as a basis for future monitoring surveys. As much as possible current conditions of the lake were compared to past observations where field sites coincided with those of historical studies. Littoral stations (0-20m) showed higher temperatures, pH, turbidities and electrical conductivity while Secchi depths and dissolved oxygen were lower compared to pelagic ones. Deeper pelagic sites experience thermal stratification, leading to strong differences between surface and deep water layers especially in terms of temperature and dissolved oxygen except for June through August during which the lake achieves complete mixing in all stations. On average, littoral stations have higher total nitrogen, chlorophyll, organic matter as well as total particulate carbon. Phytoplankton production and biomass in shallow inshore sites is light-limited due to self shading and the latter can therefore sustain higher algal biomasses because of limited mixing depths. Nitrogen often limits algal growth except for Cyanobacteria that can fix atmospheric nitrogen to meet their N limitations. The higher algal biomass accounts for the higher TN concentrations, chlorophyll and organic matter at littoral sites. During thermal stratification, TP and SRP concentrations are comparable in littoral and pelagic sites while during and just after mixing, both fractions of P are higher in the littoral areas. Continuous excess SRP and the ability of Cyanobacteria to fix atmospheric nitrogen create nutrient saturated conditions that result in light limitation for algal growth. Annual rainfall is characterised by two peaks in the stratification seasons 2 and 3 and appears to be the main source of nutrient enrichment in the lake, particularly TP. Decomposition of organic matter during the stratification period results into release of TP and Si into deeper waters where they build up to much greater concentration than in surface waters. TN reaches annual minimum during the deep mixing period because of N-poor deep waters. Chlorophyll concentrations also reach their annual minimum at this time as deep mixing imposes strong light limitation on algal growth and nitrogen fixation especially in pelagic areas. Comparisons with historical records show that the lake today is warmer than in the 1960s but with lower oxygen and pH in the deeper waters. Thus deep water respiration rates, oxygen consumption and CO2 are higher in the 2000s largely attributed to the eutrophication of the lake. Oxygen depletion in deeper waters during thermal stratification has led to loss of habitat for fish and other biota. Chlorophyll levels, phosphorus concentrations and electrical conductivity in both littoral and pelagic stations have increased compared to records of the 1960s. On the other hand nitrogen concentrations around marginal bays and gulfs have not shown a marked increase compared to historical records of the 1960s and 1970s. Dissolved silicon in the pelagic areas has decreased 5-20 times compared to historical records as eutrophication has increased Si demand by diatoms relative to rather constant supply from the catchment. In line with increased algal turbidities, Secchi depths have decreased at least two-fold since the 1960s. The need for lake wide regular water quality surveys and basin developments in support of appropriate management interventions can not be overemphasized at present in order to determine whether the lake is continuing along the same trends over time documented in this report.
    Description: Published
    Keywords: Water quality ; Physicochemical properties ; Environmental monitoring ; Nitrogen ; Phytoplankton ; Freshwater lakes
    Repository Name: AquaDocs
    Type: Report Section , Not Known
    Format: pp.62-80
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    The Contribution of Atmospheric Deposition to the Nutrient Budget of Winam Gulf of Lake Victoria. (2015)
    Lake Victoria Environment Management Project (LVEMP) | Kisumu, Kenya
    Details
    Publication Date: 2021-05-19
    Description: Concern has been raised about the contribution of atmospheric deposition to the nutrient flux of Lake Victoria. A few studies on the atmospheric deposition over the African Great Lakes have shown that the atmospheric deposition is a significant source of Total Nitrogen (TN) and Total Phosphorus (TP) to lakes and in fact by far the highest contributor of N and P on the lake surface. This has been attributed to the large scale destruction of soil cover as a result of changes in the land use system, improper agricultural practices and transport from other regions through regional and global air circulation. The objective of this study was to estimate the amount of TP and TN coming from the atmosphere and to compliment measurement from the catchment in order to estimate a nutrient mass balance for Winam Gulf. Two stations were selected for this study, Kadenge and Kisumu. Both wet and dry atmospheric samples were collected in an acid rinsed bucket mounted on a metal structure 1.5m from the ground and analysed for TP and TN using standard methods. It was observed that the annual dry deposition rates for both TP and TN were higher than the wet ones. Dry TP. 575.2 tonnes/year, wet TP. 472.8 tonnes/year giving a total of 1048 tonnes/year with dry P accounting for 55% and wet P 45%. Dry TN. 10289.98 tonnes/year, wet TN. 12133.6 tonnes/year and a total of 22423.6 tonnes/year and dry N accounting for 46% and wet N 54 %. Compared with estimates of TP and TN from the catchment studies these represent about 38% TP and about 70% TN to the Winam Gulf (Kenyan side of L.Victoria) If these rates are applied to the whole lake surface assuming that there is no major difference in deposition rates across the lake, it was estimated that 17515.5 tonnes of TP and 373727.2 tonnes of TN was deposited per year with dry P accounting for more than 50% of TP and dry N accounts for more than 50% of TN. These estimates have been made from two land-based stations and therefore there is need for the inshore stations to be established. It is therefore necessary as a management strategy to eutrophication in Lake Victoria, to address the atmospheric deposition alongside other sources of nutrients to the lake.
    Description: Published
    Keywords: Phosphorus ; Nitrogen ; Water quality ; Eutrophication
    Repository Name: AquaDocs
    Type: Book Section , Not Known
    Format: pp.80-101 [Chapter 4]
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    Upward nitrate transport by phytoplankton in oceanic waters : balancing nutrient budgets in oligotrophic seas (2015)
    PeerJ
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PeerJ 2 (2014): e302, doi:10.7717/peerj.302.
    Description: In oceanic subtropical gyres, primary producers are numerically dominated by small (1–5 µm diameter) pro- and eukaryotic cells that primarily utilize recycled nutrients produced by rapid grazing turnover in a highly efficient microbial loop. Continuous losses of nitrogen (N) to depth by sinking, either as single cells, aggregates or fecal pellets, are balanced by both nitrate inputs at the base of the euphotic zone and N2-fixation. This input of new N to balance export losses (the biological pump) is a fundamental aspect of N cycling and central to understanding carbon fluxes in the ocean. In the Pacific Ocean, detailed N budgets at the time-series station HOT require upward transport of nitrate from the nutricline (80–100 m) into the surface layer (∼0–40 m) to balance productivity and export needs. However, concentration gradients are negligible and cannot support the fluxes. Physical processes can inject nitrate into the base of the euphotic zone, but the mechanisms for transporting this nitrate into the surface layer across many 10s of m in highly stratified systems are unknown. In these seas, vertical migration by the very largest (102–103 µm diameter) phytoplankton is common as a survival strategy to obtain N from sub-euphotic zone depths. This vertical migration is driven by buoyancy changes rather than by flagellated movement and can provide upward N transport as nitrate (mM concentrations) in the cells. However, the contribution of vertical migration to nitrate transport has been difficult to quantify over the required basin scales. In this study, we use towed optical systems and isotopic tracers to show that migrating diatom (Rhizosolenia) mats are widespread in the N. Pacific Ocean from 140°W to 175°E and together with other migrating phytoplankton (Ethmodiscus, Halosphaera, Pyrocystis, and solitary Rhizosolenia) can mediate time-averaged transport of N (235 µmol N m-2 d-1) equivalent to eddy nitrate injections (242 µmol NO3− m-2 d-1). This upward biotic transport can close N budgets in the upper 250 m of the central Pacific Ocean and together with diazotrophy creates a surface zone where biological nutrient inputs rather than physical processes dominate the new N flux. In addition to these numerically rare large migrators, there is evidence in the literature of ascending behavior in small phytoplankton that could contribute to upward flux as well. Although passive downward movement has dominated models of phytoplankton flux, there is now sufficient evidence to require a rethinking of this paradigm. Quantifying these fluxes is a challenge for the future and requires a reexamination of individual phytoplankton sinking rates as well as methods for capturing and enumerating ascending phytoplankton in the sea.
    Description: This work has been funded by the National Science Foundation: OCE-0726726, OCE-0094591, OCE-9414372, OCE-9100888 and OCE-9415923 to TAV, and OCE-9423471 to CHP.
    Keywords: Vertical migration ; Diatoms ; Marine ; Nitrogen ; Dinoflagellates ; Rhizosolenia ; Nitrate ; Biological pump ; Gyres ; Mixed layer
    Repository Name: Woods Hole Open Access Server
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    Global oceanic emission of ammonia : constraints from seawater and atmospheric observations (2015)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 29 (2015): 1165–1178, doi:10.1002/2015GB005106.
    Description: Current global inventories of ammonia emissions identify the ocean as the largest natural source. This source depends on seawater pH, temperature, and the concentration of total seawater ammonia (NHx(sw)), which reflects a balance between remineralization of organic matter, uptake by plankton, and nitrification. Here we compare [NHx(sw)] from two global ocean biogeochemical models (BEC and COBALT) against extensive ocean observations. Simulated [NHx(sw)] are generally biased high. Improved simulation can be achieved in COBALT by increasing the plankton affinity for NHx within observed ranges. The resulting global ocean emissions is 2.5 TgN a−1, much lower than current literature values (7–23 TgN a−1), including the widely used Global Emissions InitiAtive (GEIA) inventory (8 TgN a−1). Such a weak ocean source implies that continental sources contribute more than half of atmospheric NHx over most of the ocean in the Northern Hemisphere. Ammonia emitted from oceanic sources is insufficient to neutralize sulfate aerosol acidity, consistent with observations. There is evidence over the Equatorial Pacific for a missing source of atmospheric ammonia that could be due to photolysis of marine organic nitrogen at the ocean surface or in the atmosphere. Accommodating this possible missing source yields a global ocean emission of ammonia in the range 2–5 TgN a−1, comparable in magnitude to other natural sources from open fires and soils.
    Description: NSF Grant Numbers: AGS-1020594, EF-0424599; WHOI Grant Number: AGS-0328342; UVA; UK SOLAS Knowledge Transfer; SOLAS Project Integration Grant Number: NE/E001696/1
    Description: 2016-02-13
    Keywords: Ocean ; Ammonia ; Nitrogen ; Natural
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    Plant ecology. Anthropogenic environmental changes affect ecosystem stability via biodiversity (2015)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2015-04-18
    Description: Human-driven environmental changes may simultaneously affect the biodiversity, productivity, and stability of Earth's ecosystems, but there is no consensus on the causal relationships linking these variables. Data from 12 multiyear experiments that manipulate important anthropogenic drivers, including plant diversity, nitrogen, carbon dioxide, fire, herbivory, and water, show that each driver influences ecosystem productivity. However, the stability of ecosystem productivity is only changed by those drivers that alter biodiversity, with a given decrease in plant species numbers leading to a quantitatively similar decrease in ecosystem stability regardless of which driver caused the biodiversity loss. These results suggest that changes in biodiversity caused by drivers of environmental change may be a major factor determining how global environmental changes affect ecosystem stability.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hautier, Yann -- Tilman, David -- Isbell, Forest -- Seabloom, Eric W -- Borer, Elizabeth T -- Reich, Peter B -- New York, N.Y. -- Science. 2015 Apr 17;348(6232):336-40. doi: 10.1126/science.aaa1788.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK. Department of Ecology, Evolution and Behavior, University of Minnesota Twin Cities, Saint Paul, MN 55108, USA. Ecology and Biodiversity Group, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, Netherlands. yann.hautier@plants.ox.ac.uk. ; Department of Ecology, Evolution and Behavior, University of Minnesota Twin Cities, Saint Paul, MN 55108, USA. Bren School of the Environment, University of California, Santa Barbara, CA 93106, USA. ; Department of Ecology, Evolution and Behavior, University of Minnesota Twin Cities, Saint Paul, MN 55108, USA. ; Department of Forest Resources, University of Minnesota, Saint Paul, MN 55108, USA. Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, NSW 2753, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25883357" target="_blank"〉PubMed〈/a〉
    Keywords: *Biodiversity ; Carbon Dioxide ; Fires ; Herbivory ; *Human Activities ; Humans ; Nitrogen ; *Plants ; Water
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Soil science. Soil and human security in the 21st century (2015)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2015-05-09
    Description: Human security has and will continue to rely on Earth's diverse soil resources. Yet we have now exploited the planet's most productive soils. Soil erosion greatly exceeds rates of production in many agricultural regions. Nitrogen produced by fossil fuel and geological reservoirs of other fertilizers are headed toward possible scarcity, increased cost, and/or geopolitical conflict. Climate change is accelerating the microbial release of greenhouse gases from soil organic matter and will likely play a large role in our near-term climate future. In this Review, we highlight challenges facing Earth's soil resources in the coming century. The direct and indirect response of soils to past and future human activities will play a major role in human prosperity and survival.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Amundson, Ronald -- Berhe, Asmeret Asefaw -- Hopmans, Jan W -- Olson, Carolyn -- Sztein, A Ester -- Sparks, Donald L -- New York, N.Y. -- Science. 2015 May 8;348(6235):1261071. doi: 10.1126/science.1261071. Epub 2015 May 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA. earthy@berkeley.edu. ; Life and Environmental Sciences Unit, University of California, Merced, CA 95343, USA. ; Land, Air, and Water Resources, One Shields Avenue, Davis, CA 95616, USA. ; Climate Change Program Office, Office of the Chief Economist, U.S. Department of Agriculture (USDA), 14th and Independence SW, Washington, DC 20013, USA. ; Board on International Scientific Organizations, National Academy of Sciences, 500 Fifth Street NW, Washington, DC 20001, USA. ; Plant and Soil Science, Chemistry and Biochemistry, Civil and Environmental Engineering, and Marine Science and Policy, University of Delaware, Newark, DE 19716, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25954014" target="_blank"〉PubMed〈/a〉
    Keywords: Agriculture/trends ; Climate Change ; *Conservation of Natural Resources ; Fertilizers ; Food Supply ; Fossil Fuels ; Humans ; Nitrogen ; *Soil ; *Survival
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    The role of regenerated nitrogen for rocky shore productivity, Cape Flattery, Washington, 2010 & 2011 (2014)
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Details
    Publication Date: 2022-05-25
    Description: Five datasets resulting from experiments on nitrogen regeneration in tidal pools, with and without mussls, and with two species of macroalgae,
    Description: Stable isotope tracers were added to exposed tidepools utilizing them as temporary mesocosms to quantify N transformation rates (Pather et al.,L&O). Large tracer signals were observed over the typical 4-5 hr experimental period in both the dilution of the isotope label in its added form (NH4+ or NO3-) and the appearance of the label in products (e.g. NO2-) The primary advantage was that all members of community participated in the experiment allowing us to recognize the complexity of nitrogen cycling in this system. A full dataset description is included in the supplemental file 'project-data-description.pdf'. Field names are included in the files, '*_params.csv'
    Description: Funding Source Award Number NSF Division of Ocean SciencesOCE-0928232 NSF Division of Ocean SciencesOCE-0928152 NSF Division of Ocean SciencesOCE-0928015
    Keywords: Research Subject Categories::NATURAL SCIENCES ; Corallina vancouveriensis ; Prionitis sternbergii ; Ammonium ; Nitrogen
    Repository Name: Woods Hole Open Access Server
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    Investigating the role of trichodesmium spp. in the oceanic nitrogen cycle through observations and models (2014)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2014
    Description: The nitrogen fixation and abundance of Trichodesmium colonies and their connections with physical processes were investigated through Video Plankton Recorder (VPR) and other observations collected in fall 2010 and spring 2011 in the western subtropical–tropical North Atlantic. A data processing procedure for estimating rare taxon abundance was devised to leverage the accuracy of manual classification and the effort savings of automatic classification. In fall 2010, local maxima in colony abundance were observed in a series of cyclones. We hypothesized Ekman transport convergence/divergence in cyclones/anticyclones as a driving mechanism and investigated the process using idealized three-dimensional models. Elevated abundances in anticyclones in spring 2011 were correlated with anomalously fresh water connected to river outflow. A bio-optical model based on carbon-normalized nitrogen fixation rates measured in fall 2010 and spring 2011 was used to estimate nitrogen fixation over the VPR transects. Mean VPR-based estimates of abundance and volume-specific nitrogen fixation rates at depth in the tropical North Atlantic were not inconsistent with estimates derived from conventional sampling methods compiled in a database by Luo et al. (2012). These findings did not reveal the systematic underestimation of deep colony populations and nitrogen fixation hypothesized by Davis and McGillicuddy (2006).
    Description: This work was supported through a NASA Earth and Space Science Fellowship (NASA NNX11AL59H Understanding the role of the nitrogen- xing cyanobacterium Trichodesmium in the oceanic nitrogen and carbon cycles: in situ measurement, satellite observation, and biogeochemical modeling) as well as fellowship support from the Ocean Life Institute and Academic Programs O ce at WHOI. Additional grant support was provided by NSF OCE-0925284 Quanti cation of Trichodesmium spp. Vertical and Horizontal Abundance Patterns and Nitrogen Fixation in theWestern North Atlantic, NSF OCE-1048897 MOBY: Modeling Ocean Variability and Biogeochemical Cycles, NASA NNX13AE47G Physical and Biological Dynamics of Nonlinear Mesoscale Eddies: Satellite Observations, in situ Measurements, and Numerical Simulations on a Global Scale, and NASA NNX08AL71G Carbon cycling in the North Atlantic from regional to basin scales: satellite data, in situ observations, and numerical models.
    Keywords: Nitrogen ; Ocean currents ; Oceanus (Ship : 1975-) Cruise OC469 ; Oceanus (Ship : 1975-) Cruise OC471
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    River export of nutrients and organic matter from the North Slope of Alaska to the Beaufort Sea (2014)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Water Resources Research 50 (2014): 1823–1839, doi:10.1002/2013WR014722.
    Description: While river-borne materials are recognized as important resources supporting coastal ecosystems around the world, estimates of river export from the North Slope of Alaska have been limited by a scarcity of water chemistry and river discharge data. This paper quantifies water, nutrient, and organic matter export from the three largest rivers (Sagavanirktok, Kuparuk, and Colville) that drain Alaska's North Slope and discusses the potential importance of river inputs for biological production in coastal waters of the Alaskan Beaufort Sea. Together these rivers export ∼297,000 metric tons of organic carbon and ∼18,000 metric tons of organic nitrogen each year. Annual fluxes of nitrate-N, ammonium-N, and soluble reactive phosphorus are approximately 1750, 200, and 140 metric tons per year, respectively. Constituent export from Alaska's North Slope is dominated by the Colville River. This is in part due to its larger size, but also because constituent yields are greater in the Colville watershed. River-supplied nitrogen may be more important to productivity along the Alaskan Beaufort Sea coast than previously thought. However, given the dominance of organic nitrogen export, the potential role of river-supplied nitrogen in support of primary production depends strongly on remineralization mechanisms. Although rivers draining the North Slope of Alaska make only a small contribution to overall river export from the pan-arctic watershed, comparisons with major arctic rivers reveal unique regional characteristics as well as remarkable similarities among different regions and scales. Such information is crucial for development of robust river export models that represent the arctic system as a whole.
    Description: Funding for this project was provided by a grant from the National Science Foundation Office of Polar Programs (NSF-OPP-0436118) as part of the Arctic System Science (ARCSS) Study of the Northern Alaska Coastal System (SNACS) effort.
    Description: 2014-08-28
    Keywords: River ; Coastal ; Arctic ; Nutrients ; Carbon ; Nitrogen
    Repository Name: Woods Hole Open Access Server
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    Stem, root, and older leaf N:P ratios are more responsive indicators of soil nutrient availability than new foliage (2014)
    Ecological Society of America
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © Ecological Society of America, 2014. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecology 95 (2014): 2062–2068, doi:10.1890/13-1671.1.
    Description: Foliar nitrogen to phosphorus (N:P) ratios are widely used to indicate soil nutrient availability and limitation, but the foliar ratios of woody plants have proven more complicated to interpret than ratios from whole biomass of herbaceous species. This may be related to tissues in woody species acting as nutrient reservoirs during active growth, allowing maintenance of optimal N:P ratios in recently produced, fully expanded leaves (i.e., “new” leaves, the most commonly sampled tissue). Here we address the hypothesis that N:P ratios of newly expanded leaves are less sensitive indicators of soil nutrient availability than are other tissue types in woody plants. Seedlings of five naturally established tree species were harvested from plots receiving two years of fertilizer treatments in a lowland tropical forest in the Republic of Panama. Nutrient concentrations were determined in new leaves, old leaves, stems, and roots. For stems and roots, N:P ratios increased after N addition and decreased after P addition, and trends were consistent across all five species. Older leaves also showed strong responses to N and P addition, and trends were consistent for four of five species. In comparison, overall N:P ratio responses in new leaves were more variable across species. These results indicate that the N:P ratios of stems, roots, and older leaves are more responsive indicators of soil nutrient availability than are those of new leaves. Testing the generality of this result could improve the use of tissue nutrient ratios as indices of soil nutrient availability in woody plants.
    Description: Data are from Santiago et al. (2012), which was supported by a grant from the Andrew W. Mellon Foundation to S. J. Wright, a Smithsonian Institute Scholarly Studies grant to S. J. Wright and J. B. Yavitt, and a University of California Regent’s Faculty Fellowship to L. S. Santiago. L. A. Schreeg was partially supported through a Marine Biological Laboratory-Brown University SEED grant to Z. Cardon, S. Porder, and L. A. Schreeg.
    Keywords: Barro Colorado Nature Monument, Panama ; Forests ; Nitrogen ; N:P ratios ; Phosphorus ; Soil nutrient availability ; Stoichiometry ; Woody plants
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    Assessment of nitrogen flows into the Cuban landscape (2013)
    Details
    Publication Date: 2021-05-19
    Description: The alteration of the nitrogen (N) cycle by human activities is widespread and has often resulted in increased flows of nitrogen to the marine environment. In this paper we have attempted to know the changes of N fluxes in Cuba by quantifying the N inputs to the landscape from (1) fertilizer applications, (2) atmospheric deposition, (3) biological nitrogen fixation and (4) net import of food and feeds. N-inputs to the country progressively increased until the end of the 20th century, reaching a peak during the 80s when low cost fertilizer imported from the former Soviet Union led to heavy rates of application. This rapid growth represented more than a 5-fold increase with respect to pristine values; higher than the two-fold global increase of anthropogenic N reported by Vitousek et al. (1997 Human alteration of the global nitrogen cycle: sources and consequences. Ecol. Appl. 7:737-750). Inorganic fertilizer was the largest single source of reactive N, followed by atmospheric deposition, biological fixation, and net imports of foods and feedstocks. Nitrogen inputs peaked in 1987 and data expressed on an area basis show that N flux to the Cuban landscape, in the 80s, was one of the highest reported in the literature. During the 90s, there was a dramatic drop in nitrogen inputs mainly associated to a decrease in the use of inorganic fertilizer. Other factors reducing nutrient inflows to Cuba, during the same period, were imports of foodstuff and livestock feeds, a decrease of nitrogen oxide emissions, and a decrease in the sugar cane crop area. Using an empirical relationship (Howarth et al. 1996 Regional nitrogen budgets and riverine N & O fluxes for the drainages to the North Atlantic Ocean: Natural and human influences. Biogeochemistry 35:75-139) we present a very preliminary estimate of N-inputs to coastal waters and discuss the consequences of these changes on the coastal zone.
    Description: La alteración del ciclo del nitrógeno (N) por la actividad humana está muy extendida y con frecuencia se ha traducido en un aumento de los flujos de nitrógeno en el medio ambiente marino. En este trabajo hemos tratado de conocer los cambios de los flujos de N en Cuba mediante la cuantificación de los aportes de N en el paisaje a partir de (1) la aplicación de fertilizantes, (2) la deposición atmosférica, (3) la fijación biológica de nitrógeno y (4) la importación neta de alimentos y se alimenta. N-entradas al país aumentó progresivamente hasta el final del siglo 20, alcanzando un pico en los años 80 cuando el fertilizante de bajo coste importados de la antigua Unión Soviética condujeron a fuertes tasas de aplicación. Este rápido crecimiento representa un aumento de más de 5 veces con respecto a los valores prístinos, más alto que el aumento global de dos veces de N antropogénico informó Vitousek et al. (1.997 alteración humana del ciclo global del nitrógeno:... Causas y consecuencias Appl Ecol 7:737-750). Fertilizante inorgánico fue la mayor fuente de reactivo N, seguido de la deposición atmosférica, la fijación biológica, y las importaciones netas de alimentos y materias primas. Los aportes de nitrógeno alcanzó su punto máximo en 1987 y los datos expresados ​​en función de demostración área que N fundente al paisaje cubano, en los años 80, fue una de las más altas reportadas en la literatura. Durante los años 90, se produjo una dramática caída en los aportes de nitrógeno asociadas principalmente a la disminución en el uso de fertilizantes inorgánicos. Otros factores que reducen los flujos de nutrientes a Cuba, durante el mismo período, fueron las importaciones de alimentos y piensos de ganado, una disminución de las emisiones de óxido de nitrógeno, y una disminución en el área de cultivo de caña de azúcar. Utilizando una relación empírica (Howarth et al 1996 los presupuestos regionales de nitrógeno y los flujos fluviales N & O para los drenajes en el Océano Atlántico Norte:.. Influencias naturales y humanas se presenta una estimación muy preliminar de N-entradas a las aguas costeras y discutir las consecuencias de estos cambios en la zona costera.
    Description: Published
    Description: nitrógeno
    Description: flujos
    Description: ciclo del nitrógeno
    Keywords: Atmospheric deposition ; Fertilizers ; Nitrogen ; Nitrogen cycle
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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    Nitrogen isotopes in chlorophyll and the origin of Eastern Mediterranean sapropels (2013)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-25
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 1997
    Description: The goals of this thesis were: (1) to establish methods for the determination of nitrogen and carbon isotope ratios in marine particulate and sedimentary chlorophyll derivatives; (2) to establish chlorophyll δ15N and δl3C as proxies for the nitrogen and carbon isotopic composition of marine phytoplankton; and (3) to use chlorophyll nitrogen isotopic ratios to understand the origin of Late Quaternary Eastern Mediterranean sapropels. Techniques are presented for the determination of chlorin nitrogen and carbon isotopic ratios in marine particles and sediments with a precision greater than 0.15 per mil for both isotopes. The procedure can be performed in about 4 hours for particulate and 8 hours for sediment samples, and relies on multiple chromatographic purifications. About 20 g of a moderately organic-rich sediment are required. A technique is also presented for the determination of chlorin nitrogen and carbon isotopic ratios by isotope-ratio monitoring gas chromatography-mass spectrometry (irmGC-MS) by synthesizing bis-(tert.-butyldimethylsiloxy)Si(IV) chlorin derivatives. However, yields for the 4-step synthesis were only about 5-6% and there was a net isotopic depletion of 1.2 (± 0.3) per mil in the derivative, relative to the starting material. These techniques are then used to show that the nitrogen isotopic difference between chlorophyll and whole cells in six species of marine phytoplankton is 5.16 ± 2.40 per mil. For carbon, the isotopic difference between chlorophyll and whole cells in five species of marine phytoplankton is -0.02 ± 2.12 per mil. A model of the distribution of 15N in phytoplankton is constructed and it is demonstrated that the interspecies variability observed for the nitrogen isotopic difference between chlorophyll and whole cells can be attributed to differences in the partitioning of cellular nitrogen between non-protein biochemicals. In the field, where mixed assemblages of phytoplankton prevail, the isotopic difference beween chlorophyll and whole cells is expected to tend toward the average value of 5.16 per mil. Finally, the average nitrogen isotopic composition of chlorins from six Late Quaternary Eastern Mediterranean sapropels (-5.01 + 0.38 per mil) was found to be very similar to the δ15N of chlorophyll from the modem deep chlorophyll maximum (-6.38 ± 1.80 per mil) in the Eastern Mediterranean. In addition, sapropel photoautotrophic material, calculated from the chlorin δ15N, had the same isotopic composition (0.15 per mil) as both bulk sapropel sediments (-0.08 ± 0.53 per mil) and deep water nitrate (-0.05 per mil). These data suggest (a) that bottom waters were anoxic, (b) that organic matter burial efficiency was enhanced, and (c) that oligotrophic conditions similar to today persisted, in the Eastern Mediterranean during sapropel deposition. These results contradict earlier interpretations of Late Quaternary bulk sedimentary δ15N in the Eastern Mediterranean. The latter concluded that the pattern of high δ15N values in intercalated marl oozes and low values in sapropels was the result of decreased nutrient utilization, and hence, increased primary production, during sapropel events. The low δ15N of deep water nitrate in the Eastern Mediterranean suggests a significant source of new nitrogen from biological N2-fixation. It is suggested that attempts to reconstruct the nitrogen isotopic composition of marine organic matter in the past by measuring the δ15N of whole sediments may be subject to misinterpretation due to the alteration of isotopic ratios during diagenesis. The partial oxidation of marine organic matter can result in significant isotopic enrichment of the preserved residual. The magnitude of this enrichment appears to be large when bottom waters are well-oxygenated, and small when bottom waters are anoxic. Environments where large temporal reqox changes have occurred are expected to be the most problematic for the interpretation of bulk sedimentary δ15N. In these environments, the diagenetic signal can be at least as large as the primary isotopic signal being sought. The Eastern Mediterranean Sea during the Late Quaternary appears to be one such environment.
    Description: Funding for this work came from an Office of Naval Research Graduate Fellowship, the Woods Hole Oceanographic Institution Ocean Ventures Fund, and a Petroleum Research Grant(# 30124-AC2).
    Keywords: Nitrogen ; Isotopes ; Nitrates ; Chlorophyll ; Stratigraphic geology ; Geochemistry ; Sapropel ; Marine sediments ; Le Suroit (Ship) Minos Cruise ; Thomas G. Thompson (Ship) Cruise TN041 ; Knorr (Ship : 1970-) Cruise KN134-08 ; Moana Wave (Ship) Cruise MW87-08
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    Deforestation of watersheds of Panama : nutrient retention and export to streams (2013)
    Springer
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biogeochemistry 115 (2013): 299-315, doi:10.1007/s10533-013-9836-2.
    Description: A series of eight watersheds on the Pacific coast of Panama where conversion of mature lowland wet forest to pastures by artisanal burning provided watershed-scale experimental units with a wide range of forest cover (23, 29, 47, 56, 66, 73, 73, 91, and 92%). We used these watersheds as a landscape-scale experiment to assess effects of degree of deforestation on within-watershed retention and hydrological export of atmospheric inputs of nutrients. Retention was estimated by comparing rainfall nutrient concentrations (volume-weighted to allow for evapotranspiration) to concentrations in freshwater reaches of receiving streams. Retention of rain-derived nutrients in these Panama watersheds averaged 77, 85, 80, and 62% for nitrate, ammonium, dissolved organic N, and phosphate, respectively. Retention of rain-derived inorganic nitrogen, however, depended on watershed cover: retention of nitrate and ammonium in pasture-dominated watersheds was 95 and 98%, while fully forested watersheds retained 65 and 80% of atmospheric nitrate and ammonium inputs. Watershed forest cover did not affect retention of dissolved organic nitrogen and phosphate. Exports from more forested watersheds yielded DIN/P near 16, while pasture-dominated watersheds exported N/P near 2. The differences in magnitude of exports and ratios suggest that deforestation in these Panamanian forests results in exports that affect growth of plants and algae in the receiving stream and estuarine ecosystems. Watershed retention of dissolved inorganic nitrogen calculated from wet plus dry atmospheric deposition varied from 90% in pasture- to 65% in forest-dominated watersheds, respectively. Discharges of DIN to receiving waters from the watersheds therefore rose from 10% of atmospheric inputs for pasture-dominated watersheds, to about 35% of atmospheric inputs for fully forested watersheds. These results from watersheds with no agriculture or urbanization, but different conversion of forest to pasture by burning, show significant, deforestation-dependent retention within tropical watersheds, but also ecologically significant, and deforestation-dependent, exports that are biologically significant because of the paucity of nutrients in receiving tropical stream and coastal waters.
    Description: This work was funded by NSF Grant BIO- 0842413
    Keywords: Tropical watersheds ; Forests ; Pastures ; Nitrogen ; Phosphorus ; Evapotranspiration ; Groundwater
    Repository Name: Woods Hole Open Access Server
    Type: Article
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    The role of biological production in pleistocene atmospheric carbon dioxide variations and the nitrogen isotope dynamics of the southern ocean (2013)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-25
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1997
    Description: This dissertation contributes to the search for a cause of glacial/interglacial variations in atmospheric carbon dioxide. The hypotheses addressed involve changes in low and high-latitude biological export production. A modelling exercise demonstrates that the paleoceanographic record of calcite preservation places constraints on hypothesized changes in low latitude biological production. The model results indicate that large, production-driven changes in the depth of the calcite saturation horizon during the last ice age would have caused a similar deepening of the calcite lysocline, even when the effect of sediment respiration-driven dissolution is considered. Such a large glacial lysocline deepening is not evident on an ocean-average basis. The results indicate very few mechanisms by which low latitude production could have driven Pleisotocene carbon dioxide variations, generally arguing against a low latitude cause for these variations. The use of N isotopes as a paleoceanographic proxy for nitrate utilization in Southern Ocean was investigated. In order to examine the generation of the link between nitrate utilization and N isotopes in the surface ocean, the isotopic composition of nitrate was studied. The first step in this work was the development of a new method to measure the isotopic composition of nitrate which is amenable to the generation of large, precise data sets. Results from the Southern Ocean demonstrate that the Antarctic and Subantarctic represent distinct regimes of N isotope dynamics. The findings support the use of N isotopes as a proxy for nitrate utilization in the Antarctic. A study of diatom microfossil-bound N in sediments suggests that this N is native to the diatoms, that it is invulnerable to early diagenesis, and that its isotopic compositon varies with that of the sinking flux. Paleoceanographic records of diatom-bound N isotopic composition corroborate the conclusion, previously based on bulk sediment isotopic data, that nitrate utilization was elevated in the glacial Antarctic, representing a major cause of lower glacial atmospheric carbon dioxide levels.
    Description: This research was supported by the National Science Foundation Graduate Fellowship Program, the JOI!USSAC Ocean Drilling Graduate Fellowship Program, and by NSF grant OCE-9201286 to D.C. McCorkle.
    Keywords: Nitrogen ; Isotopes ; Stable isotopes ; Paleoceanography ; Carbon dioxide ; Atmospheric carbon dioxide ; Polarstern (Ship) Cruise
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
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    Estimates of new and total productivity in central Long Island Sound from in situ measurements of nitrate and dissolved oxygen (2013)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 36 (2013): 74-97, doi:10.1007/s12237-012-9560-5.
    Description: Biogeochemical cycles in estuaries are regulated by a diverse set of physical and biological variables that operate over a variety of time scales. Using in situ optical sensors, we conducted a high-frequency time-series study of several biogeochemical parameters at a mooring in central Long Island Sound from May to August 2010. During this period, we documented well-defined diel cycles in nitrate concentration that were correlated to dissolved oxygen, wind stress, tidal mixing, and irradiance. By filtering the data to separate the nitrate time series into various signal components, we estimated the amount of variation that could be ascribed to each process. Primary production and surface wind stress explained 59% and 19%, respectively, of the variation in nitrate concentrations. Less frequent physical forcings, including large-magnitude wind events and spring tides, served to decouple the relationship between oxygen, nitrate, and sunlight on about one-quarter of study days. Daytime nitrate minima and dissolved oxygen maxima occurred nearly simultaneously on the majority (〉 80%) of days during the study period; both were strongly correlated with the daily peak in irradiance. Nighttime nitrate maxima reflected a pattern in which surface-layer stocks were depleted each afternoon and recharged the following night. Changes in nitrate concentrations were used to generate daily estimates of new primary production (182 ± 37 mg C m-2 d-1) and the f-ratio (0.25), i.e., the ratio of production based on nitrate to total production. These estimates, the first of their kind in Long Island Sound, were compared to values of community respiration, primary productivity, and net ecosystem metabolism, which were derived from in situ measurements of oxygen concentration. Daily averages of the three metabolic parameters were 1660 ± 431, 2080 ± 419, and 429 ± 203 mg C m-2 d-1, respectively. While the system remained weakly autotrophic over the duration of the study period, we observed very large day-to-day differences in the f-ratio and in the various metabolic parameters.
    Description: This work was supported by the Yale Institute for Biospheric Studies, the Sounds Conservancy of the Quebec-Labrador Foundation, and the Yale School of Forestry and Environmental Studies Carpenter-Sperry Fund.
    Description: 2014-01-01
    Keywords: Long Island Sound ; Nitrate ; Nitrogen ; New production ; In situ measurements ; Eutrophication ; Dissolved oxygen ; Net ecosystem metabolism ; Wind forcing ; Wind stress ; f-ratio
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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    Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter (2013)
    Society for Freshwater Science
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Society for Freshwater Science, 2013. This article is posted here by permission of Society for Freshwater Science for personal use, not for redistribution. The definitive version was published in Freshwater Science 32 (2013): 1111-1121, doi:10.1899/12-049.1.
    Description: Nutrient enrichment affects bacteria and fungi associated with detritus, but little is known about how biota associated with different size fractions of organic matter respond to nutrients. Bacteria dominate on fine (〈1 mm) and fungi dominate on coarse (〉1 mm) fractions, which are used by different groups of detritivores. We measured the effect of experimental nutrient enrichment on fungal and bacterial biomass, microbial respiration, and detrital nutrient content on benthic fine particulate organic matter (FPOM) and coarse particulate organic matter (CPOM). We collected FPOM and CPOM from 1 reference and 1 enriched stream. CPOM substrates consisted of 2 litter types with differing initial C:nutrient ratios (Acer rubrum L. and Rhododendron maximum L.). Fungal and bacterial biomass, respiration, and detrital nutrient content changed with nutrient enrichment, and effects were greater on CPOM than on FPOM. Fungal biomass dominated on CPOM (99% total microbial biomass), whereas bacterial biomass dominated on FPOM (95% total microbial biomass). These contributions were unchanged by nutrient enrichment. Bacterial and fungal biomass increased more on CPOM than FPOM. Respiration increased more on CPOM (up to 300% increase) than FPOM (50% increase), indicating important C-loss pathways from these resources. Microbial biomass and detrital nutrient content were positively related. Greater changes in nutrient content were observed on CPOM than on FPOM, and changes in detrital C:P were greater than changes in detrital C:N. Threshold elemental ratios analyses indicated that enrichment may reduce P limitation for shredders and exacerbate C limitation for collector-gatherers. Changes in CPOM-dominated pathways are critical in predicting shifts in detrital resource quality and C flow that may result from nutrient enrichment of detritus-based systems.
    Description: This study and preparation of this manuscript were supported by National Science Foundation grants DEB-0318063 (to ADR, K. Suberkropp, B. Wallace, and M. Black) and DEB-0918894 (to ADR, J. Benstead, V. Gulis, and J. Maerz) and an Odum School of Ecology Graduate Research grant to CJT.
    Description: 2014-09-17
    Keywords: Nitrogen ; Phosphorus ; Headwater stream ; Carbon ; Detritus ; Shredder ; Fungi ; Bacteria ; Aquatic ; Freshwater ; Coweeta Hydrologic Laboratory ; Southern Appalachian Mountains
    Repository Name: Woods Hole Open Access Server
    Type: Article
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    Environment. Latin America's nitrogen challenge (2013)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2013-04-13
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Austin, A T -- Bustamante, M M C -- Nardoto, G B -- Mitre, S K -- Perez, T -- Ometto, J P H B -- Ascarrunz, N L -- Forti, M C -- Longo, K -- Gavito, M E -- Enrich-Prast, A -- Martinelli, L A -- New York, N.Y. -- Science. 2013 Apr 12;340(6129):149. doi: 10.1126/science.1231679.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Universidad de Buenos Aires, IFEVA-CONICET, Buenos Aires, Argentina.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23580515" target="_blank"〉PubMed〈/a〉
    Keywords: Agriculture ; Biomass ; *Conservation of Natural Resources ; *Ecosystem ; *Environment ; Human Activities ; Humans ; Latin America ; Nitrogen ; *Nitrogen Cycle ; Politics ; Public Health ; Public Policy
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Optical magnetic imaging of living cells (2013)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2013-04-27
    Description: Magnetic imaging is a powerful tool for probing biological and physical systems. However, existing techniques either have poor spatial resolution compared to optical microscopy and are hence not generally applicable to imaging of sub-cellular structure (for example, magnetic resonance imaging), or entail operating conditions that preclude application to living biological samples while providing submicrometre resolution (for example, scanning superconducting quantum interference device microscopy, electron holography and magnetic resonance force microscopy). Here we demonstrate magnetic imaging of living cells (magnetotactic bacteria) under ambient laboratory conditions and with sub-cellular spatial resolution (400 nanometres), using an optically detected magnetic field imaging array consisting of a nanometre-scale layer of nitrogen-vacancy colour centres implanted at the surface of a diamond chip. With the bacteria placed on the diamond surface, we optically probe the nitrogen-vacancy quantum spin states and rapidly reconstruct images of the vector components of the magnetic field created by chains of magnetic nanoparticles (magnetosomes) produced in the bacteria. We also spatially correlate these magnetic field maps with optical images acquired in the same apparatus. Wide-field microscopy allows parallel optical and magnetic imaging of multiple cells in a population with submicrometre resolution and a field of view in excess of 100 micrometres. Scanning electron microscope images of the bacteria confirm that the correlated optical and magnetic images can be used to locate and characterize the magnetosomes in each bacterium. Our results provide a new capability for imaging bio-magnetic structures in living cells under ambient conditions with high spatial resolution, and will enable the mapping of a wide range of magnetic signals within cells and cellular networks.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3641584/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3641584/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Le Sage, D -- Arai, K -- Glenn, D R -- DeVience, S J -- Pham, L M -- Rahn-Lee, L -- Lukin, M D -- Yacoby, A -- Komeili, A -- Walsworth, R L -- R01 GM084122/GM/NIGMS NIH HHS/ -- R01GM084122/GM/NIGMS NIH HHS/ -- England -- Nature. 2013 Apr 25;496(7446):486-9. doi: 10.1038/nature12072.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23619694" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteria/*cytology/metabolism ; *Diamond/chemistry ; Magnetic Fields ; *Magnetic Phenomena ; Magnetosomes/chemistry/metabolism ; *Microbial Viability ; Microscopy/instrumentation/*methods ; Nanoparticles/analysis/chemistry ; Nitrogen
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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    Nanometre-scale thermometry in a living cell (2013)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2013-08-02
    Description: Sensitive probing of temperature variations on nanometre scales is an outstanding challenge in many areas of modern science and technology. In particular, a thermometer capable of subdegree temperature resolution over a large range of temperatures as well as integration within a living system could provide a powerful new tool in many areas of biological, physical and chemical research. Possibilities range from the temperature-induced control of gene expression and tumour metabolism to the cell-selective treatment of disease and the study of heat dissipation in integrated circuits. By combining local light-induced heat sources with sensitive nanoscale thermometry, it may also be possible to engineer biological processes at the subcellular level. Here we demonstrate a new approach to nanoscale thermometry that uses coherent manipulation of the electronic spin associated with nitrogen-vacancy colour centres in diamond. Our technique makes it possible to detect temperature variations as small as 1.8 mK (a sensitivity of 9 mK Hz(-1/2)) in an ultrapure bulk diamond sample. Using nitrogen-vacancy centres in diamond nanocrystals (nanodiamonds), we directly measure the local thermal environment on length scales as short as 200 nanometres. Finally, by introducing both nanodiamonds and gold nanoparticles into a single human embryonic fibroblast, we demonstrate temperature-gradient control and mapping at the subcellular level, enabling unique potential applications in life sciences.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4221854/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4221854/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kucsko, G -- Maurer, P C -- Yao, N Y -- Kubo, M -- Noh, H J -- Lo, P K -- Park, H -- Lukin, M D -- 1P50HG006193-01/HG/NHGRI NIH HHS/ -- 5DP1OD003893-03/OD/NIH HHS/ -- DP1 DA035083/DA/NIDA NIH HHS/ -- England -- Nature. 2013 Aug 1;500(7460):54-8. doi: 10.1038/nature12373.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23903748" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Survival ; Color ; Fibroblasts/*cytology ; Gold ; Humans ; Metal Nanoparticles/*chemistry ; Nanodiamonds/*chemistry ; Nanotechnology/instrumentation ; Nitrogen ; Single-Cell Analysis ; Temperature ; *Thermometers ; Thermometry/*instrumentation/*methods
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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    Impacts of biodiversity loss escalate through time as redundancy fades (2012)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2012-05-05
    Description: Plant diversity generally promotes biomass production, but how the shape of the response curve changes with time remains unclear. This is a critical knowledge gap because the shape of this relationship indicates the extent to which loss of the first few species will influence biomass production. Using two long-term (〉/=13 years) biodiversity experiments, we show that the effects of diversity on biomass productivity increased and became less saturating over time. Our analyses suggest that effects of diversity-dependent ecosystem feedbacks and interspecific complementarity accumulate over time, causing high-diversity species combinations that appeared functionally redundant during early years to become more functionally unique through time. Consequently, simplification of diverse ecosystems will likely have greater negative impacts on ecosystem functioning than has been suggested by short-term experiments.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Reich, Peter B -- Tilman, David -- Isbell, Forest -- Mueller, Kevin -- Hobbie, Sarah E -- Flynn, Dan F B -- Eisenhauer, Nico -- New York, N.Y. -- Science. 2012 May 4;336(6081):589-92. doi: 10.1126/science.1217909.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22556253" target="_blank"〉PubMed〈/a〉
    Keywords: *Biodiversity ; Biomass ; *Ecosystem ; Fabaceae/growth & development ; Minnesota ; Nitrogen ; Nitrogen Cycle ; Plant Development ; *Plants ; *Poaceae/growth & development ; Soil/chemistry ; Time Factors
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Preliminary geochemical characterization of volcanic and geothermal fluids discharged from the Ecuadorian volcanic arc. (2011)
    Blackwell
    Details
    Publication Date: 2021-06-16
    Description: In Ecuador, magmatism results from the subduction of the Nazca Plate beneath the North Western part of South America. North of 2.5°S, the Ecuadorian Quaternary volcanic arc is characterized by about 60 volcanoes distributed along three different parallel NNE-striking chains. Many of these volcanoes are potentially active or currently in activity displaying associated geothermal fields. South of this latitude, no active arc is present in Ecuador. Few geochemical studies of the discharged fluids in this region have been attempted, mainly related to geothermal exploration. Nevertheless, a complete study of the fluids of the volcanic arc is lacking. The aim of this work is to present the first systematic geochemical characterization of discharged fluids from the entire Ecuadorian volcanic arc. In order to achieve this objective, 56 samples of thermal and cold waters, as well as 32 dissolved and 27 bubbling gases, were collected from North to South across the arc and analyzed for determination of the main geochemical parameters. A chemical study reflects the physical and chemical processes undergone by these cold and thermal waters during their circulation through the different host rocks. The chemistry of the dissolved gases, are characterized by He and CO2 contents, 2 to 3 orders of magnitude higher than the ASW values implies very active gas-water interaction processes. Moreover, both dissolved and bubbling gases isotopic signature shows a wide compositional range, with Helium ranging between 0.1 to 7.12 R/Ra and carbon ranging from -1.75 to -10.50 13C(TDIC) vs PDB standard. Such isotopic features may be related to the presence of at least two distinct end-members: mantle and crustal.. Helium, Nitrogen, Carbon, Oxygen and Deuterium isotopic signatures will help us to identify and characterize the main end-members of fluids involved in Ecuador’s continental arc-volcanism. Moreover, on the basis of the chemistry of thermal waters and associated bubbling gases the characteristics and the potential resources of the different geothermal fields are being investigated.
    Description: Published
    Description: 525-541
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: gases ; isotopes ; Helium ; Nitrogen ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Extreme methane deuterium, nitrogen and helium enrichment in natural gas from the Homorod seep (Romania) (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Methane (CH4) in terrestrial environments, whether microbial, thermogenic, or abiogenic, exhibits a large variance in C and H stable isotope ratios due to primary processes of formation. Isotopic variability can be broadened through secondary, post-genetic processes, such as mixing and isotopic fractionation by oxidation. The highest and lowest 13C and 2H (or D, deuterium) concentrations in CH4 found in various geologic environments to date, are defined as “natural” terrestrial extremes. We have discovered a new extreme in a natural gas seep with values of deuterium concentrations, δDCH4, up to+124‰that far exceed those reported for any terrestrial gas. The gas, seeping from the small Homorod mud volcano in Transylvania (Romania), also has extremely high concentrations of nitrogen (N92 vol.%) and helium (up to 1.4 vol.%). Carbon isotopes in CH4, C2H6 and CO2, and nitrogen isotopes in N2 indicate a primary organic sedimentary origin for the gas (a minor mantle component is suggested by the 3He/4He ratio, R/Ra~0.39). Both thermogenic gas formation modeling and Rayleigh fractionation modeling suggest that the extreme deuterium enrichment could be explained by an oxidation process characterised by a δDCH4 and δ13CCH4 enrichment ratio (ΔH/ΔC) of about 20, and may be accounted for by abiogenic oxidation mediated by metal oxides. All favourable conditions for such a process exist in the Homorod area, where increased heat flow during Pliocene–Quaternary volcanism may have played a key role. Finally we observed rapid variations (within 1 h) in C and H isotope ratios of CH4, and in the H2S concentrations which are likely caused by mixing of the deep oxidized CH4–N2–H2S–He rich gas with a microbial methane generated in the mud pool of one of the seeps. We hypothesize that the unusual features of Homorod gas can be the result of a rare combination of factors induced by the proximity of sedimentary organic matter, mafic, metal-rich volcanic rocks and salt diapirs,leading to the following processes: a) primary thermogenic generation of gas at temperatures between 130 and 175 °C; b) secondary alteration through abiogenic oxidation, likely triggered by the Neogene–Quaternary volcanism of the eastern Transylvanian margin; and c) mixing at the surface with microbial methane that formed through fermentation in the mud volcano water pool. The Homorod gas seep is a rare example that demonstrates how post-genetic processes can produce extreme gas isotope signatures (thus far only theorized), and that extremely positive δDCH4 values cannot be used to unambiguously distinguish between biotic and abiotic origin.
    Description: Published
    Description: 89-96
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Methane ; Deuterium ; Nitrogen ; Helium ; Seep ; Mud volcano ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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    Root standing crop and chemistry after six years of soil warming in a temperate forest (2011)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Tree Physiology 31 (2011): 707-717, doi:10.1093/treephys/tpr066.
    Description: Examining the responses of root standing crop (biomass and necromass) and chemistry to soil warming is crucial for understanding root dynamics and functioning in the face of global climate change. We assessed the standing crop, total nitrogen (N) and carbon (C) compounds in tree roots and soil net N mineralization over the growing season after six years of experimental soil warming in a temperate deciduous forest in 2008. Roots were sorted into four different categories: live and dead fine roots (≤ 1 mm in diameter) and live and dead coarse roots (1-4 mm in diameter). Total root standing crop (live plus dead) in the top 10 cm of soil in the warmed area was 42.5% (378.4 vs. 658.5 g m-2) lower than in the control area, while the live root standing crops in the warmed area was 62% lower than in the control area. Soil net N mineralization over the growing season increased by 79.4% in the warmed relative to the control area. Soil warming did not significantly change the concentrations of C and carbon compounds (sugar, starch, hemicellulose, cellulose, and lignin) in the four root categories. However, total N concentration in the live fine roots in the warmed area was 10.5% (13.7 vs. 12.4 mg g-1) higher and C:N ratio was 8.6% (38.5 vs. 42.1) lower than in the control area. The increase in N concentration in the live fine roots could be attributed to the increase in soil N availability due to soil warming. Net N mineralization was negatively correlated to both live and dead fine roots in the mineral soil that is home to the majority of roots, suggesting that soil warming increases N mineralization, decreases fine root biomass, and thus decreases carbon allocation belowground.
    Description: This study was funded by the US National Science Foundation (NSF-AGS-1005663) and the Marine Biological Laboratory (to JT), China Scholarship Council (to YZ), Harvard Forest Long Term Ecological Research (NSF-DEB-0620443) and the National Institute for Climate Change Research (DOE-DE-FCO2-06-ER64157) (to JM).
    Description: 2012-08-02
    Keywords: Carbon ; Nitrogen ; Root biomass ; Root diameter ; Root necromass
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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    Denitrification across landscapes and waterscapes : a synthesis (2011)
    Ecological Society of America
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Ecological Society of America, 2006. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 16 (2006): 2064–2090, doi:10.1890/1051-0761(2006)016[2064:DALAWA]2.0.CO;2.
    Description: Denitrification is a critical process regulating the removal of bioavailable nitrogen (N) from natural and human-altered systems. While it has been extensively studied in terrestrial, freshwater, and marine systems, there has been limited communication among denitrification scientists working in these individual systems. Here, we compare rates of denitrification and controlling factors across a range of ecosystem types. We suggest that terrestrial, freshwater, and marine systems in which denitrification occurs can be organized along a continuum ranging from (1) those in which nitrification and denitrification are tightly coupled in space and time to (2) those in which nitrate production and denitrification are relatively decoupled. In aquatic ecosystems, N inputs influence denitrification rates whereas hydrology and geomorphology influence the proportion of N inputs that are denitrified. Relationships between denitrification and water residence time and N load are remarkably similar across lakes, river reaches, estuaries, and continental shelves. Spatially distributed global models of denitrification suggest that continental shelf sediments account for the largest portion (44%) of total global denitrification, followed by terrestrial soils (22%) and oceanic oxygen minimum zones (OMZs; 14%). Freshwater systems (groundwater, lakes, rivers) account for about 20% and estuaries 1% of total global denitrification. Denitrification of land-based N sources is distributed somewhat differently. Within watersheds, the amount of land-based N denitrified is generally highest in terrestrial soils, with progressively smaller amounts denitrified in groundwater, rivers, lakes and reservoirs, and estuaries. A number of regional exceptions to this general trend of decreasing denitrification in a downstream direction exist, including significant denitrification in continental shelves of N from terrestrial sources. Though terrestrial soils and groundwater are responsible for much denitrification at the watershed scale, per-area denitrification rates in soils and groundwater (kg N·km−2·yr−1) are, on average, approximately one-tenth the per-area rates of denitrification in lakes, rivers, estuaries, continental shelves, or OMZs. A number of potential approaches to increase denitrification on the landscape, and thus decrease N export to sensitive coastal systems exist. However, these have not generally been widely tested for their effectiveness at scales required to significantly reduce N export at the whole watershed scale.
    Description: This work was supported in part by grants from the U.S. National Science Foundation (EAR0355366, DEB0332237, DEB0443439) and National Aeronautics and Space Administration (NNG04GL68G).
    Keywords: Continental shelf ; Denitrification ; Estuaries ; Lakes ; Nitrogen ; Oxygen minimum zones ; Rivers ; Sediments ; Soils
    Repository Name: Woods Hole Open Access Server
    Type: Article
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    Seasonal and hydrologic drivers of dissolved organic matter and nutrients in the upper Kuparuk River, Alaskan Arctic (2011)
    Springer
    Details
    Publication Date: 2022-05-26
    Description: © The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Biogeochemistry 103 (2011): 109-124, doi:10.1007/s10533-010-9451-4.
    Description: As the planet warms, widespread changes in Arctic hydrology and biogeochemistry have been documented and these changes are expected to accelerate in the future. Improved understanding of the behavior of water-borne constituents in Arctic rivers with varying hydrologic conditions, including seasonal variations in discharge–concentration relationships, will improve our ability to anticipate future changes in biogeochemical budgets due to changing hydrology. We studied the relationship between seasonal water discharge and dissolved organic carbon and nitrogen (DOC and DON) and nutrient concentrations in the upper Kuparuk River, Arctic Alaska. Fluxes of most constituents were highest during initial snowmelt runoff in spring, indicating that this historically under-studied period contributes significantly to total annual export. In particular, the initial snowmelt period (the stream is completely frozen during the winter) accounted for upwards of 35% of total export of DOC and DON estimated for the entire study period. DOC and DON concentrations were positively correlated with discharge whereas nitrate (NO3 −) and silicate were negatively correlated with discharge throughout the study. However, discharge-specific DOC and DON concentrations (i.e. concentrations compared at the same discharge level) decreased over the summer whereas discharge-specific concentrations of NO3 − and silicate increased. Soluble reactive phosphorus (SRP) and ammonium (NH4 +) were negatively correlated with discharge during the spring thaw, but were less predictable with respect to discharge thereafter. These data provide valuable information on how Arctic watershed biogeochemistry will be affected by future changes in temperature, snowfall, and rainfall in the Arctic. In particular, our results add to a growing body of research showing that nutrient export per unit of stream discharge, particularly NO3 −, is increasing in the Arctic.
    Description: Funding provided by the National Science Foundation, NSF-OPP- 0436118.
    Keywords: Arctic ; Stream ; Headwaters ; Carbon ; Nitrogen ; Nutrients
    Repository Name: Woods Hole Open Access Server
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  • 84
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    Nitrogen stable isotopes in the shell of Mercenaria mercenaria trace wastewater inputs from watersheds to estuarine ecosystems (2011)
    Inter-Research
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © Inter-Research, 2008. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Aquatic Biology 4 (2008): 99-111, doi:10.3354/ab00106.
    Description: We tested the usefulness of δ15N values in the organic matrix of whole shells from Mercenaria mercenaria as tracers of anthropogenic nitrogen inputs to coastal ecosystems. Low and high stringency acidification methods were used to define parameters for reliable δ15N determination in shell material for comparison with δ15N values in soft tissues. δ15N values in shell from transplanted and native clams reflected %-wastewater contribution to estuaries, but were 2.3 to 2.5% lighter than δ15N values in soft tissues. Accuracy of δ15N values in shell material depended on recovering a sufficient quantity of organic N from shell (~70 µg) and was not altered by acidification method. Reliable δ15N values were obtained with as little as 80 mg of shell and using 100 µl of acid, but higher stringency methods (treating more shell with more acid for longer duration) typically yielded more N for subsequent stable isotope analysis. Conversely, higher concentrations of acid reduced N recovery. These results suggest that the content of N recovered was of greater concern to obtaining reliable δ15N values from shell material than acidification effects. Differences between δ15N values in shell material and soft tissues likely reflected differences in N assimilation among tissues. In combination with other analyses, this method may be applied to refine modern and historical trophic assessments and discern natural from anthropogenic influences on coastal ecosystems
    Description: This work was funded by the Sea Grant Program of the Massachusetts Institute of Technology (Award 20-240-9011-5).
    Keywords: Acidification ; Bivalve ; Carbonate ; Tissue ; Nitrogen ; Stable isotope ; Anthropogenic
    Repository Name: Woods Hole Open Access Server
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  • 85
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    Ecology. Resilience to blooms (2011)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2011-10-08
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brookes, Justin D -- Carey, Cayelan C -- New York, N.Y. -- Science. 2011 Oct 7;334(6052):46-7. doi: 10.1126/science.1207349.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉School of Earth and Environmental Science, University of Adelaide, Adelaide 5005, Australia. justin.brookes@adelaide.edu.au〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21980099" target="_blank"〉PubMed〈/a〉
    Keywords: Biomass ; Climate Change ; Cyanobacteria/*growth & development ; *Ecosystem ; *Eutrophication ; Fresh Water/*microbiology ; Nitrogen ; Phosphorus ; Phytoplankton/growth & development ; Temperature ; *Water Microbiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 86
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    Essai d’évaluation de la qualite des eaux de ruissellement du bassin versant de la lagune de Bizerte (2010)
    INSTM
    Details
    Publication Date: 2021-05-19
    Description: La lagune de Bizerte, située en Tunisie nord-orientale, constitue un bassin récepteur d’un réseau hydrographique bien développé. Afin d’apprécier l’impact des facteurs naturels et anthropiques sur les eaux de ruissellement du bassin versant de cette lagune, une campagne de prélèvement d’eau a été effectuée en février 2003 (période de crue) au niveau de la partie aval de quinze cours d’eau, à raison d’un échantillon par cours d’eau. Les échantillons d’eau prélevés ont fait l’objet de mesure in situ des variables physico-chimiques (température, pH et O2 dissous) et d’analyses au laboratoire de la chlorophylle a et des différentes formes organiques et inorganiques dissoutes de l’azote et du phosphore. Les résultats obtenus ont montré que les eaux de ruissellement sont, dans l’ensemble, bien oxygénées et, sont neutres à légèrement alcalines. Celles prélevées au niveau de la partie aval des oueds Merazig et Guenniche, situés respectivement au Nord-Ouest et au Sud-Est de la lagune de Bizerte, sont généralement, les plus chargées en composés azotés et phosphorés. L’application de l’analyse en composante principale (ACP) sur ces résultats fait apparaître, globalement, deux groupes d’eau et confirme que les eaux des oueds Merazig et Guenniche se distinguent de celles des autres cours d’eau.
    Description: تقع بحيرة بنزرت في الشمال التونسي وتغذيها عدة أودية تنبع من حوض يمتد على مساحة شاسعة. وتمثل التقلبات المناخية والأنشطة الإقتصادية المتزايدة في السنوات الأخيرة أهم العوامل المؤثرة في هذا الحوض وفي السيول التي تنبع منه في اتجاه البحيرة. لقد قمنا في شهر فيفري في سنة 2003 باقتـاء عينات من الماء مـن 15 مصـب لتحليلـها ( درجة الحرارة، درجة الحموضة، نسبة الأكسجين، الكلوروفيل والمواد العضوية والمعدنية الأزوتية والفسفورية) قصد دراسة هذه الظاهرة. وبينت النتائج التي تم الحصول عليها بأن مياه روافد بحيرة بنزرت تتميز عموما بنسبة عالية للأكسجين وبدرجة حموضة عادية إلى مرتفعة نوعا ما. لكن مياه مصب وادي المرازيق وقنيش والذين يقعان بالتوالي في الشمال الغربي والجنوب الشرقي للبحيرة محملا بأكثر نسبة من المواد الأزوتية والفسفورية. تظهر هذه النتيجة واضحة في التحاليل الإحصائية والتي تفصل بين مصب هذين الوادين ومصب بقية الأودية.
    Description: The lagoon of Bizerte, located on north-eastern Tunisia, constitute a receiving basin of a well expanding hydrographic network. In order to assess the impact of natural and anthropogenic factors on the runoff water of the catchment area of this lagoon, a sampling campaign of water was carried out on February 2003 (period of the rise in the water level) on the downstream of fifteen streams. The samples of water collected were subject to in situ measure of physico-chemical parameters (Temperature, pH and dissolved oxygen) and laboratory analyses of chlorophyll a and the different organic and inorganic dissolved forms of nitrogen and phosphorus. Results showed that the runoff waters are, on the whole, well oxygenated and are neuter to thoughtlessly alkaline. Those sampled on the downstream of Merazig and Guenniche rivers, situated respectively on the north-west and on the south-east of Bizerte lagoon, are, on the whole, the most loaded with nitrogen and phosphorus compounds. The application of the principal component analysis (PCA) to these data showed two groups of water and confirmed that the water of Merazig and Guenniche rivers stand out from the others.
    Description: Published
    Keywords: Chemical properties ; Nitrogen ; Phosphorus ; Runoff ; Water quality ; Chlorophylls ; Anthropogenic factors ; Physical properties ; Anthropogenic factors ; Chemical properties ; Chlorophylls ; Nitrogen ; Phosphorus ; Physical properties ; Pollution monitoring ; Runoff ; Water quality
    Repository Name: AquaDocs
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    Caractérisation hivernale de la lagune de Bizerte (2010)
    INSTM
    Details
    Publication Date: 2021-05-19
    Description: Ce travail porte sur la caractérisation hivernale de la lagune de Bizerte en se basant sur une campagne de mesures effectuée en janvier 2004. Cette campagne a porté sur 17 stations réparties sur toute la lagune ainsi qu’une station marine de référence. Chaque échantillon a fait l’objet de mesures in-situ (Température, Salinité, Conductivité, Transparence, Acidité et Oxygène dissous) et des analyses au laboratoire (NO3, NO2, NT, PO4, Chlorophylle-a, Phéopigment et MES). Cette étude a montré que la distribution spatiale des paramètres est fortement liée aux apports fluviaux. Contrairement au phosphore minéral, la teneur en azote total montre une variation spatiale importante. L’analyse de la distribution spatiale des nutriments d’une part et de la chlorophylle-a d’autre part suggère (que le phosphore minéral est un facteur limitant pour la production primaire) une relation étroite entre la biomasse phytoplanctonique et la disponibilité du phosphore minéral. Une caractérisation spatiale de la lagune a été effectuée au moyen d’une Classification Hiérarchique Ascendante (CAH) permettant le regroupement des stations ainsi qu’une Analyse en Composantes Principales (ACP) qui a permis la caractérisation multivariée des stations. La Méthode des Vecteurs Equivalents (MVE) a été par la suite utilisée pour identifier les paramètres hydrobiologiques expliquant la plus grande part de la variance totale de l’ensemble des données. L’analyse statistique a permis de distinguer quatre zones le chenal de navigation (y compris le goulet), la zone conchylicole, la zone littorale et la partie centrale.
    Description: اهتمت هذه الدّراسة بتقييم بحيرة بنزرت من خلال انتشار العوامل الهيدرو بيولوجية بها و ذلك بالإعتماد على 17 محطة منتشرة علي كامل البحيرة. خضعت على عيّنة لقياسات أنيّة على عين المكان (الحرارة ، الملوحة، التواصل الكهربائي، الشفافية، الحموضة و كمية الأكسجين في الماء) و لتحاليل مخبريّة ( النتريت، النترات، النتروجين الكلّي، الفسفور الرّباعي، اليخضور "أ"، صبغ الفيتوبلانكتون و المواد العالقة). لقد أبرزت هذه الدّراسة أنّ انتشار العوامل الهيدروبيولوجية مرتبط أساسا بحمولة مياه السّيلان و الأوديّة والتيارات المائية كما ابرزّ تحليل انتشار المواد المغذية و اليخضورعلاقة متميزة بين كميّة الفيتوبلانكتونات و الفسفور الرّباعي. لقد مكنت هذه الدّراسة بالإعتماد على طرق إحصائية مختلفة من تحديد أربعة مناطق تتشابه نوعيّة الماء بها، وهي : قنال البحيرة، منطقة تربية المحّار، المناطق السّاحلية و المنطقة الوسطى للبحيرة.
    Description: This work concerns the winter characterization of the lagoon of Bizerte based on series of measurement taken in January 2004 (winter season). This sampling has interested 17 stations distributed in the lagoon and a reference marine station. Each sample was the subject of in-situ measurements (Temperature, Salinity, Conductivity, Transparency, Suspended matter, Acidity and dissolved Oxygen) and of the analyses in the laboratory (NO3 NO2 , NT, PO4 , Chlorophyll-a, Pheopigment and MES). For better characterizing the state of the lagoon a statistical analysis was applied to the hydrobiological data obtained. This analysis consists in applying the technique of Principal Components Analysis (ACP) and the technique of the Ascending Hierarchical Clustering (CAH) with flexible bonds. The last stage consists in using the Method of the Equivalent Vectors (EVM) in order to identify the significant hydrobiological parameters. This study showed that the space distribution of the parameters is strongly related to the contributions of fresh waters. With the opposition to mineral phosphorus the total nitrogen content shows a significant space variation. The analysis of the spatial distribution of the nutriments on the one hand and chlorophyll-a on the other hand suggests a close connection between the quantity of the phytoplankton and the availability of mineral phosphorus. The statistical analysis made it possible to distinguish five areas the Narrow part, the conchylaceous zone, the littoral zone, the eastern, the western part and the central part.
    Description: Published
    Keywords: Geographical distribution ; Nitrogen ; Phosphorus ; Phytoplankton ; Hydrobiology ; Geographical distribution ; Hydrobiology ; Nitrogen ; Nutrients (mineral) ; Phosphorus ; Phytoplankton
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    Compuestos de nitrógeno y fósforo en las aguas superficiales de tres zonas de la plataforma marina cubana (2010)
    Instituto de Oceanología
    Details
    Publication Date: 2021-05-19
    Description: Entre los años 1990 y 1991 se estudió el Golfo de Guacanayabo, desde 1998 hasta 2003 se evaluó el Golfo de Batabanó y el Archipiélago Sabana Camagüey fue investigado en la etapa 2001-2005, con el objetivo de evaluar los contenidos de nitrógeno y fósforo en estas tres regiones de la plataforma marina cubana y establecer las relaciones existentes entre ambos nutrientes. Los golfos de Guacanayabo y Batabanó poseen un mayor potencial de nitrógeno y fósforo que el ecosistema costero Sabana-Camagüey, debido al menor desarrollo de la red fluvial en este ecosistema, aunque en las tres regiones las concentraciones de estos compuestos están bajo una acentuada influencia antropogénica. La relación nitrógeno total-fósforo total N.T./P.T., mostró una tendencia a decrecer en regiones con cobertura de pastos marinos, atribuido a las cantidades de fósforo que aportar los mismos a la matriz agua, aunque predominaron los valores en que ninguno de los nutrientes es restrictivo y a diferencia de la relación nitrógeno total inorgánico-fósforo inorgánico NTI/P no tiene un patrón bien definido en los diferentes períodos climáticos
    Description: The Gulf of Guacanayabo was studied in 1990 and 1991. The Gulf of Batabanó was evaluated from 1998 to 2003, and Sabana-Camagüey Archipelago was investigated in the stage 2001-2005. The objective of these researches was to evaluate nitrogen and phosphorus contents in these three regions of Cuban marine shelf and to establish the relations existing between both nutrients. The gulfs of Guacanayabo and Batabanó have a greater nitrogen and phosphorus potential than Sabana-Camagüey coastal ecosystem, due to the lesser development of the fluvial network in this ecosystem; although in the three regions the concentrations of these compounds receive a marked anthropogenic influence. The total nitrogen-total phosphorus ratio, N.T./P.T., showed a tendency to decrease in regions with seagrass cover, attributed to the amounts of phosphorus that this biotope contributes to the water matrix, although the predominant values were those in which none of the nutrients is restrictive, and unlike the total inorganic nitrogen-inorganic phosphorus ratio, NTI/P, it does not have a well-defined pattern in the different climatic periods.
    Description: Published
    Description: nitrógeno, fósforo, eutroficación, nitrogen, phosphorus, eutrophication
    Keywords: Eutrophication ; Nitrogen ; Phosphorus ; Eutrophication ; Nitrogen ; Phosphorus ; Man-induced effects ; Archipelagoes
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    Caracterización química de los sedimentos superficiales de las bahías de Cárdenas y Santa Clara, Archipiélago Sabana-Camagüey, Cuba. (2010)
    Instituto de Oceanología
    Details
    Publication Date: 2021-05-19
    Description: Los sedimentos superficiales de las bahías de Cárdenas y Santa Clara fueron muestreados en mayo de 2002 y julio de 2005, evaluándose los parámetros orgánicos e inorgánicos que tienen mayor peso en los ciclos biogeoquímicos (carbón, nitrógeno, fósforo, carbonatos, sulfuro de hidrógeno y consumo de oxidante químico). Los sedimentos de las bahías de Cárdenas y Santa Clara, poseen notables contenidos de carbón orgánico y concentraciones de nitrógeno inferiores a 0,2 %, evidenciando que la fuente principal de materia orgánica en estos cuerpos de agua es la vegetación periférica y acuática, rica en carbono y pobre en nitrógeno. En estas bahías las concentraciones promedio de carbonatos son superiores al 35 %, aunque la mayor riqueza corresponde a la bahía de Santa Clara, sobre todo en los puntos más alejados de la línea de costa. Los montos de sulfuro de hidrógeno en ambas bahías fueron similares, en el caso de la bahía de Cárdenas tuvo un valor medio de 20,49 mM m-2 y en la de Santa Clara la concentración promedio fue 20,10 mM m-2. Los valores superiores se registraron en la etapa de seca y no se correlacionan de forma directa con los contenidos de carbón orgánico y consumo de oxidante químico.
    Description: The superficial sediments of Cárdenas and Santa Clara Bays were sampled in May 2002 and July 2005, being evaluated the organic and inorganic parameters that have greater importance in biogeochemical cycles (carbon, nitrogen, phosphorous, carbonates, hydrogen sulphides and consumption of chemical oxidant). The sediments of Cárdenas and Santa Clara Bays possess remarkable contents of organic carbon and nitrogen concentrations lower than 0,2 %, evidencing that the main source of organic matter in these water bodies is the peripheral and aquatic vegetation, rich in carbon and poor in nitrogen. In these bays, the average concentrations of carbonates are higher than 35%; although the greatest richness corresponds to Santa Clara Bay, mainly in the points farther from the coastline. The values of hydrogen sulphides were similar in both bays. In the case of Cárdenas Bay, it had a mean value of 20,49 mm m-2; and in Santa Clara the average concentration was 20,10 mm m-2. The higher values registered in the dry season and are not directly correlated with the contents of organic carbon and consumption of chemical oxidant.
    Description: Published
    Description: Sedimento, carbón orgánico, nitrógeno, sulfuro de hidrógeno, bahías
    Keywords: Nitrogen ; Hydrogen sulphide ; Sediments ; Organic carbon ; Nitrogen ; Hydrogen sulphide ; Bays
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    Etude comparative de l’absorption de l’azote par deux espèces d’algues rouges : 〈Gracilaria verrucosa〉 (Hudson) papenfuss, 1950 et Gracilaria 〈Bursa-pastoris〉 (gmelin) silva, 1952. (2010)
    INSTM
    Details
    Publication Date: 2021-05-19
    Description: Afin de mettre en évidence l’aptitude de deux espèces d’algues rouges Gracilaria verrucosa et Gracilaria bursa-pastoris pour le traitement des effluents et leur utilisation potentielle, une série d’expériences a été réalisée ayant pour but d’expliquer le comportement de ces deux espèces d’algues vis à vis de la source d’azote. Dans une première expérience, on a pu déterminer la forme d’azote (N-NH4 , N-NO3) preférentielle pour chacune des deux espèces d’algues cultivées séparément. Elles ont une nette préférence pour N-NH4 et cela pour une même concentration initiale. Cependant, G. verrucosa est un candidat plus performant que G. bursa-pastoris pour l’assimilation des deux formes d’azote. Etant identifié comme source préférentielle, N-NH4 a été utilisé à différentes concentrations, dans une deuxième expérience, pour comprendre son effet sur le taux et la vitesse d’assimilation ainsi que le taux de croissance spécifique chez les deux espèces d’algues. Au bout des deux premiers jours de culture et selon la concentration initiale, 65 à 75% de cette concentration a été absorbée. Les taux d’assimilation de l’N-NH4 par G. verrucosa et G. bursa-pastoris dans les cultures à concentration inférieure à 400 µmol/l n’ont pas montré de différence significative. Pour G. verrucosa, le taux maximum d’assimilation est obtenu dans les cultures où la concentration de l’N-NH4 est de 400 et 500 µmol/l. Par contre, pour G. bursa-pastoris, son taux d’assimilation a diminué dans les cultures à concentration supérieure à 400 µmol/l. Le taux de croissance spécifique moyen a été de 2,2% J-1 et 1,5% J-1, respectivement pour G. bursa-pastoris et G. verrucosa. Bien que cette dernière espèce ait un taux d’assimilation plus important, G. bursa-pastoris a montré un taux de croissance spécifique plus élevé. Ceci est dû au fait que G.verrucosa possède une capacité de stockage de l’N-NH4 plus importante que celle de G. bursa-pastoris, qui utilise la majeure partie de l’N-NH4 assimilée pour la reconstitution de sa structure cellulaire et la synthèse des pigments photosynthétiques et des enzymes.
    Description: To study the ability of two red algae species Gracilaria verrucosa and Gracilaria Bursa-pastoris for their potential use and wastewater treatment, experiments were carried out. The experiments aim to explain the behaviour of these two algae species according to nitrogen form. In the first experiment, we determined the preferential nitrogen form (N-NH4, N-NO3) for each of the two algae species cultivated separately. We noted that the algae have a clear preference for N-NH4 and that for the same initial concentration. However, G. verrucosa has significantly higher assimilation rate for the two nitrogen forms than G. bursa-pastoris. Thus, identified as algae preferential source, N-NH4 was used under various concentrations, in a second experiment, to check its effect on the rate and velocity of assimilation and the specific growth rate of the two algae species. In the two first culture days and according to the initial concentration, 65 to 75 % of this concentration was absorbed. No significant difference have been observed between the N-NH4 assimilation rates of G. verrucosa and G. bursa-pastoris in the cultures where the initial concentration was lower than 400 µmol/l. For G. verrucosa, the maximum assimilation rate was obtained in the cultures where the initial N-NH4 concentration was 400 and 500 µmol/l. On the other hand, G. bursa-pastoris decreased its assimilation rate in the cultures with initial concentration higher than 400 µmol/l. The specific growth rate average were 2,2 % J-1 and 1,5 % J-1, respectively, for G. bursa-pastoris and G. verrucosa. Although the latter specie has a more important assimilation rate, G. bursa-pastoris showed a higher specific growth rate. This is due to the fact that G. verrucosa has a N-NH4 storage capacity more important than that of G. bursa-pastoris, which uses the major part of the absorbed N-NH4 for the reconstitution of its cellular structure and for photosynthetic pigments and enzymes synthesis.
    Description: لدراسة إستعداد نوعين من الطحالب الحمراء Gracilaria verrucosa و Gracilaria bursa pastoris لتنقية المياه و إعادة إستعمالهما، قمنا ببعض التجارب التي ترمي الى توضيح استجابة هذه الطحالب عند وجودها في وسط غني بمادة الآزوط التي هي في نفس الوقت مصدر تلوث الوسط البحري وعامل نمو ضروري للطحالب. في تجربة أولى، قمنا بتحديد ما إذا كان الأمونيوم N-NH4)) أو النيترات(N-NO3) هو الشكل المفضل للإمتصاص من طرف النوعين من الطحالب كل على حدى. لقد لاحظنا إمتصاص سريع للأزوت في شكل الأمونيوم. وتجدر الإشارة الى أن النوع G. verrucosa يتمتع بقدرة إمتصاص أكبر من التي يتمتع بها G. bursa pastoris . ثم في تجربة ثانية حاولنا فهم مدى تأثير الكمية الأولية للأمونيوم على نسبة وسرعة التمثل من جهة ونسبة النمو النوعي من جهة أخرى وهذا بإستعمال كميات مختلفة من الأمونيوم المضافة الى مياه تربية النوعين من الطحالب. بينت النتائج أن أعلى نسبة التمثل للأمونيوم من طرف G.verrucosa قدرت في أوساط الإستزراع ذات 400و500 ميكرومول/لتر من الأمونيوم .أما بالنسبة لـ G. bursa pastoris كانت في الأوساط ذات 400 ميكرومول/لتر.
    Description: Published
    Description: Gracilaria bursa pastoris, Gracilaria verrucosa
    Keywords: Adsorption ; Nitrogen ; Algal culture ; Wastewater treatment ; Adsorption ; Algal culture ; Nitrogen ; Nutrients (mineral) ; Wastewater treatment
    Repository Name: AquaDocs
    Type: Journal Contribution , Non-Refereed , Article
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  • 91
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    Capacité des moules dans la réduction des teneurs en nutriments et la charge bactérienne dans les effluents piscicoles (2010)
    INSTM
    Details
    Publication Date: 2021-05-19
    Description: L’effluent des élevages de poissons renferme des concentrations plus élevées en nutriments dissous et en particules en suspension que celles présentes dans l’eau entrante. Cet état entraine par conséquent, des problèmes d’ordre environnementaux affectant les eaux côtières dues à l’eutrophisation et l’augmentation de la turbidité. Afin d’améliorer la qualité de l’effluent avant son déversement dans le milieu naturel, l’utilisation des bivalves comme filtre biologique est une alternative adéquate. Cette étude analyse la capacité de la moule Mytilus galloprovincialis de réduire les teneurs en sels nutritifs et la charge bactérienne dans les effluents de loups Dicentrarchus labrax en élevage. L’effluent issu des bassins de grossissement est pompé directement dans des aquariums de 30L contenant différentes densités de moules. Trois densités de moules respectivement 24, 16 et 8 moules vivantes ont été utilisées pour tester leurs effets sur la qualité de l’eau. Les concentrations en matière particulaire, azote total, phosphore total, chlorophylle a et le nombre de bactéries dans l’effluent ont été déterminés avant et après filtration par les moules. La filtration par les moules a réduit significativement les concentrations de tous les paramètres examinés mais la densité de moule la plus élevée a entrainé l’effet le plus important. La filtration par la densité la plus élevée de moules a réduit la matière en suspension à 43% de sa valeur initiale dans l’effluent, le nombre de bactéries à 67%, l’azote total à 85% et le phosphate total à 71%. La décantation et la filtration par les moules ont réduit la concentration en chlorophylle a à 7% de sa valeur initiale.
    Description: Fish effluent water contains elevated concentrations of dissolved nutrients and suspended particulates than the influent water. Consequently, there are concerns about adverse environmental impacts on coastal waters due to eutrophication and increased turbidity. One potential method of improving effluent water quality, prior to discharge or recirculation is to use bivalves to filter the effluent. This study examines the effects of the mussel Mytilus galloprovincialis filtration on water quality of fish effluent. Effluent from a sea bass race way was pumped directly into tanks (30 L) stocked with different densities of mussels. Three densities of mussels (24, 16 and 8 live mussels per tank) were used to test their effects on water quality. The concentrations of total suspended solids, total nitrogen, total phosphorus, chlorophyll a and number of bacteria in effluent water were determined before and after filtration by mussels. The mussels significantly reduced the concentration of all the parameters examined, with the highest mussel density having the greatest effect. Filtration by the high density of mussels reduced the effluent suspended solids to 43% of the initial level, the bacterial numbers to 67% and total nitrogen to 85% and total phosphorus to 71%. Settlement and mussels filtration reduced the chlorophyll a concentration to7% of the initial effluent value.
    Description: تحتوي المياه المتأتية من تربية الأسماك على كميات مرتفعة من المواد الحيوية الذائبة و مواد مؤلفة من جزيئات إذا ما قارناها بالمياه الغير مستعملة. إلقاء هذه المياه المستعملة في البحر يندرج عنها مشاكل ذات صبغة بيئية تهم بالخصوص المياه الساحلية. من أهم الطرق لتحسين القيمة البيئية لهذه المياه المستعملة قبل وصولهاإلى البحر هو استعمال المحار كوسيلة لتنقيتها من الملوثات الناتجة عن تربية الأسماك(القاروص). تمت هذه التجربة في أحواض تسع 30 لتر وضعت في كل واحدة منها كميات مختلفة من المحار (8-16-24).لمتابعة قدرة المحار علي تنقية المياه تمت تحاليل كميات الأزوط و الفسفاط و الجزيئات العائمة و الكلوروفيل وعدد البكتيريا في الماء قبل وبعد التجربة. أتضح أن المحار له قدرة عالية في انخفاض جميع الثوابت التي وقع متابعتها في هذه التجربة . أعلى نسبة انخفاض سجلت في الأحواض ذات كمية المحار العالية. كمية المحار العالية أسفرت نتائجها علي انخفاض في كمية الجزيئات العائمة إلى %43 من قيمتها الأصلية و كمية الأزوط إلى %85 و الفسفاط إلى %71 وعدد البكتيريا إلى%67 و كمية الكورفيل إلى .7%
    Description: Published
    Description: Mytilus galloprovincialis
    Keywords: Fish ; Nitrogen ; Phosphorus ; Water quality ; Mussels ; Nutrients ; Bacteria ; Chlorophylls ; Density ; Effluents ; Filtration ; Wastewater treatment ; Aquaculture effluents ; Bacteria ; Biofilters ; Chlorophylls ; Chlorophylls ; Culture effects ; Density ; Effluents ; Filtration ; Fish ; Mussel culture ; Nitrogen ; Nutrients (mineral) ; Phosphorus ; Suspended particulate matter ; Wastewater recycling ; Wastewater treatment ; Water quality
    Repository Name: AquaDocs
    Type: Journal Contribution , Non-Refereed , Article
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  • 92
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    Compuestos de nitrógeno y fósforo en agua de algunas bahías del Archipiélago Sabana-Camagüey, Cuba. (2010)
    Details
    Publication Date: 2021-05-19
    Description: El Archipiélago Sabana – Camagüey es una de las regiones más estudiadas de la plataforma marina cubana. Entre los años 2001-2005 se evaluaron los contenidos de nitratos más nitrito, amonio, nitrógeno total, fósforo inorgánico y fósforo total, y se establecieron las relaciones nitrógeno total inorgánico & fósforo inorgánico N/P y nitrógeno total & fósforo total NT/PT, en las bahías de Cárdenas, Santa Clara Oeste, Puerto de Sagua la Grande, San Juan de los Remedios, Buenavista, Los Perros, Jigüey y La Gloria. El amonio fue la principal fuente de nitrógeno inorgánico y los contenidos de nitrógeno orgánico evidenciaron el predominio de los procesos de biosíntesis. Las relaciones N/P y NT/PT fueron superiores a 16:1 en la mayoría de las bahías estudiadas, indicando que el fósforo fue restrictivo para los productores primarios excepto en la bahía de San Juan de los Remedios.
    Description: The Sabana – Camagüey Archipelago is one of the studied regions more of the Cuban marine shelf. the bays Cárdenas, Santa Clara Oeste, Puerto de Sagua la Grande, San Juan de los Remedios, Buenavista, Los Perros, Jigüey and La Gloria were evaluated between years 2001 and 2005 the contents of nitrate more nitrito, ammonium, total nitrogen, inorganic phosphorus and total phosphorus and established the rates inorganic total nitrogen & inorganic phosphorus N/P and total nitrogen & total phosphorus NT/PT. The most important source inorganic nitrogen was the ammonium and the organic nitrogen contents confirmed the predominance of the biosynthesis processes. In the majority of the studied bays the rates N/P and NT/PT were higher than 16:1, the primary producers were limiting for phosphorus except in San Juan de los Remedios bay.
    Description: amonio, nitrógeno, fósforo y bahías.
    Keywords: Nitrogen ; Phosphorus ; Ammonium compounds ; Ammonium compounds ; Nitrogen ; Phosphorus ; Bays
    Repository Name: AquaDocs
    Type: Preprint
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  • 93
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    Pattern and variation of C:N:P ratios in China’s soils : a synthesis of observational data (2010)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Biogeochemistry 98 (2010): 139-151, doi:10.1007/s10533-009-9382-0.
    Description: Inspired by previous studies that have indicated consistent or even well-constrained relationships among carbon (C), nitrogen (N) and phosphorus (P) in soils, we have endeavored to explore general soil C:N:P ratios in China on a national scale, as well as the changing patterns of these ratios with soil depth, developmental stages and climate; we also attempted to determine if well-constrained C:N:P stoichiometrical ratios exist in China’s soil. Based on an inventory data set of 2,384 soil profiles, our analysis indicated that the mean C:N, C:P and N:P ratios for the entire soil depth (as deep as 250 cm for some soil profiles) in China were 11.9, 61 and 5.2, respectively, showing a C:N:P ratio of ~60:5:1. C:N ratios showed relatively small variation among different climatic zones, soil orders, soil depth and weathering stages, while C:P and N:P ratios showed a high spatial heterogeneity and large variations in different climatic zones, soil orders, soil depth and weathering stages. No well-constrained C:N:P ratios were found for the entire soil depth in China. However, for the 0-10 cm organic-rich soil, where has the most active organism-environment interaction, we found a well-constrained C:N ratio (14.4, molar ratio) and relatively consistent C:P (136) and N:P (9.3) ratios, with a general C:N:P ratio of 134:9:1. Finally, we suggested that soil C:N, C:P and N:P ratios in organic-rich topsoil could be a good indicator of soil nutrient status during soil development.
    Description: This study was supported by NASA Interdisciplinary Science Program (NNG04GM39C), NASA Land Cover and Land Use Change Program (NNX08AL73G_S01), and the Chinese Academy of Science ODS Program.
    Keywords: Carbon ; Nitrogen ; Phosphorus ; Stoichiometry ; China
    Repository Name: Woods Hole Open Access Server
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  • 94
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    N budgets and aquatic uptake in the Ipswich River basin, northeastern Massachusetts (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Water Resources Research 40 (2004): W11201, doi:10.1029/2004WR003172.
    Description: We calculated N budgets and conducted nutrient uptake experiments to evaluate the fate of N in the aquatic environment of the Ipswich River basin, northeastern Massachusetts. A mass balance indicates that the basin retains about 50% of gross N inputs, mostly in terrestrial components of the landscape, and the loss and retention of total nitrogen (TN) in the aquatic environment was about 9% of stream loading. Uptake lengths of PO4 and NH4 were measurable in headwater streams, but NO3 uptake was below detection (minimum detection limit = 0.05 μM). Retention or loss of NO3 was observed in a main stem reach bordered by wetland habitat. Nitrate removal in urban headwater tributaries was because of water withdrawals and denitrification during hypoxic events and in ponded wetlands with long water residence times. A mass balance using an entire river network indicates that basin-wide losses due to aquatic denitrification are considerably lower than estimates from several recent studies and range from 4 to 16% of TDN in stream loading. Withdrawals for domestic use restrict the runoff of headwater catchments from reaching the main stem during low base flow periods, thereby contributing to the spatial and temporal regulation of N export from headwater tributaries.
    Description: This research was funded by grants DEB- 9726862 and OCE-9726921 (NSF).
    Keywords: Anthropogenic ; Land use ; Uptake ; Nitrogen ; Water quality
    Repository Name: Woods Hole Open Access Server
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  • 95
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    Global N removal by freshwater aquatic systems using a spatially distributed, within-basin approach (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 22 (2008): GB2026, doi:10.1029/2007GB002963.
    Description: We explored the role of aquatic systems in the global N cycle using a spatially distributed, within-basin, aquatic nitrogen (N) removal model, implemented within the Framework for Aquatic Modeling in the Earth System (FrAMES-N). The model predicts mean annual total N (TN) removal by small rivers (with drainage areas from 2.6–1000 km2), large rivers, lakes, and reservoirs, using a 30′ latitude × longitude river network to route and process material from continental source areas to the coastal zone. Mean annual aquatic TN removal (for the mid-1990s time period) is determined by the distributions of aquatic TN inputs, mean annual hydrological characteristics, and biological activity. Model-predicted TN concentrations at basin mouths corresponded well with observations (median relative error = −12%, interquartile range of relative error = 85%), an improvement over assumptions of uniform aquatic removal across basins. Removal by aquatic systems globally accounted for 14% of total N inputs to continental surfaces, but represented 53% of inputs to aquatic systems. Integrated aquatic removal was similar in small rivers (16.5% of inputs), large rivers (13.6%), and lakes (15.2%), while large reservoirs were less important (5.2%). Bias related to runoff suggests improvements are needed in nonpoint N input estimates and/or aquatic biological activity. The within-basin approach represented by FrAMES-N will improve understanding of the freshwater nutrient flux response to anthropogenic change at global scales.
    Description: This work was funded by NASA-IDS (NNXO7AF28G, NNG04GH75G), NSF-LTER OCE-9726921, and NOAA (NA17RJ2612 – 344 to Princeton University).
    Keywords: Nitrogen ; River network ; Global
    Repository Name: Woods Hole Open Access Server
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  • 96
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    Physiological and behavioral diagnostics of nitrogen limitation for the toxic dinoflagellate Alexandrium fundyense (2010)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-26
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2000
    Description: One challenge in phytoplankton ecology is to measure species-specific physiological responses to changes in environmental conditions. Of particular importance in this regard are harmful algal bloom (RAB) species such as the toxic dinoflagellate Alexandrium fundyense which typically inhabit coastal regions where they are not usually dominant. Within the Gulf of Maine, environmental factors, specifically nitrogen, are likely to be a controlling factor for A. fundyense blooms. Therefore, the ability to ascertain the nutritional status of this species in field assemblages in critical to understanding its bloom dynamics. The aim of this thesis was to identify physiological and behavioral indicators or diagnostics of A. fundyense from the Gulf of Maine, and to evaluate these on natural populations in the Casco Bay region. Using a species-specific monoclonal antibody, two methods for identifying and separating A. fundyense from natural field assemblages were developed. The first used a species-specific antibody and flow cytometry to successfully detect and separate A. fundyense from co-occurring organisms, including other dinoflagellates of equivalent size. In particular the fluorescence associated with the antibody labeling was not sufficient of itself for species discrimination - natural red chlorophyll autofluorescence was also needed as a second parameter for identifying and sorting A. fundyense. A second antibody method was then investigated using immunomagnetic beads to successfully separate live A. fundyense from spiked field samples. The separated cells were then used to obtain accurate chlorophyll, protein and biomass estimates. CHN values were only accurate if the unbound magnetic beads were sieved from the sample prior to analysis. This is probably needed for carbohydrate analysis as well. Since A. fundyense usually inhabits coastal areas that are frequently limited by nitrogen, behavioral adaptations and intracellular responses to nitrogen availability are a primary consideration. It was therefore necessary to identify diagnostic indicators and behavioral adaptations of A. fundyense to nitrogen stress. Using laboratory water columns, nitrogen (N)-starved batch cultures, and N-limited, semi-continuous cultures, indicators of different N-nutritional states were identified. It was determined that low N concentrations in the surface of a mesocosm did not induce a Casco Bay A. fundyense isolate to vertically migrate to deep nutrient pools. Prolonged N-stress caused dramatic changes intracellular biochemistry, specifically chlorophyll a, carbohydrate, and protein content, as well as C:N, toxin content and composition. Ratios of different toxin derivatives were identified that increased with increasing N-stress and appear to be sensitive and robust indicators of N-status. Once indicators were developed for N-stress, variability in toxin content and composition were examined in the coastal waters of Casco Bay, Maine during an A. fundyense bloom in the spring of 1998. Over the course of the field season, toxin compositional changes did occur that were generally consistent with increasing levels of N-stress as the bloom progressed and N levels decreased. As observed in N-limited culture, large increases in some toxin ratios (e.g., GTX1,4:STX and NEO:STX) were observed during the latter portion of the field season, coinciding with low N:P ratios and undetectable levels of dissolved inorganic nitrogen. Overall, the toxin compositional trends are quite remarkable and suggest that this approach may provide valuable species-specific physiological information without the need for elaborate cell separation schemes such as flow cytometry or immunomagnetic bead sorting. Further laboratory studies are needed to better characterize the toxin response of A. fundyense isolates to environmental stresses before this suite of toxin indicators can be considered robust.
    Description: WHOI Education Office, National Science Foundation (NSF - OCE - 9808173), NOAA - Sea Grant - (NA86RG0075), Environmental Protection Agency - graduate fellowship (U-915038-01-0)
    Keywords: Gonyaulacaceae ; Nitrogen
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
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  • 97
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    Dynamics of N removal over annual time periods in a suburban river network (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): G03038, doi:10.1029/2007JG000660.
    Description: River systems are dynamic, highly connected water transfer networks that integrate a wide range of physical and biological processes. We used a river network nitrogen (N) removal model with daily temporal resolution to evaluate how elevated N inputs, saturation of the denitrification and total nitrate removal processes, and hydrologic conditions interact to determine the amount, timing and distribution of N removal in the fifth-order river network of a suburban 400 km2 basin. Denitrification parameters were based on results from whole reach 15NO3 tracer additions. The model predicted that between 15 and 33% of dissolved inorganic nitrogen (DIN) inputs were denitrified annually by the river system. Removal approached 100% during low flow periods, even with the relatively low and saturating uptake velocities typical of surface water denitrification. Annual removal percentages were moderate because most N inputs occurred during high flow periods when hydraulic conditions and temperatures are less favorable for removal by channel processes. Nevertheless, the percentage of annual removal occurring during above average flow periods was similar to that during low flow periods. Predicted river network removal proportions are most sensitive to loading rates, spatial heterogeneity of inputs, and the form of the removal process equation during typical base flow conditions. However, comparison with observations indicates that removal by the river network is higher than predicted by the model at moderately high flows, suggesting additional removal processes are important at these times. Further increases in N input to the network will lead to disproportionate increases in N exports due to the limits imposed by process saturation.
    Description: This work was funded by NSF-DEB- 0614282, NSF-OCE-9726921, NSF-DEB-0111410, and NSF-BCS- 0709685.
    Keywords: Nitrogen ; Removal ; Saturation ; Hydrology ; Variability
    Repository Name: Woods Hole Open Access Server
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  • 98
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    Saturn: atmosphere, ionosphere, and magnetosphere (2010)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2010-03-20
    Description: The Cassini spacecraft has been in orbit around Saturn since 30 June 2004, yielding a wealth of data about the Saturn system. This review focuses on the atmosphere and magnetosphere and briefly outlines the state of our knowledge after the Cassini prime mission. The mission has addressed a host of fundamental questions: What processes control the physics, chemistry, and dynamics of the atmosphere? Where does the magnetospheric plasma come from? What are the physical processes coupling the ionosphere and magnetosphere? And, what are the rotation rates of Saturn's atmosphere and magnetosphere?〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gombosi, Tamas I -- Ingersoll, Andrew P -- New York, N.Y. -- Science. 2010 Mar 19;327(5972):1476-9. doi: 10.1126/science.1179119.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48109, USA. tamas@umich.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20299587" target="_blank"〉PubMed〈/a〉
    Keywords: Atmosphere ; Hydrocarbons ; Light ; Magnetics ; Nitrogen ; Oxygen ; Protons ; *Saturn ; Spacecraft ; Temperature ; Tritium ; Wind
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 99
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    Significant acidification in major Chinese croplands (2010)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2010-02-13
    Description: Soil acidification is a major problem in soils of intensive Chinese agricultural systems. We used two nationwide surveys, paired comparisons in numerous individual sites, and several long-term monitoring-field data sets to evaluate changes in soil acidity. Soil pH declined significantly (P 〈 0.001) from the 1980s to the 2000s in the major Chinese crop-production areas. Processes related to nitrogen cycling released 20 to 221 kilomoles of hydrogen ion (H+) per hectare per year, and base cations uptake contributed a further 15 to 20 kilomoles of H+ per hectare per year to soil acidification in four widespread cropping systems. In comparison, acid deposition (0.4 to 2.0 kilomoles of H+ per hectare per year) made a small contribution to the acidification of agricultural soils across China.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Guo, J H -- Liu, X J -- Zhang, Y -- Shen, J L -- Han, W X -- Zhang, W F -- Christie, P -- Goulding, K W T -- Vitousek, P M -- Zhang, F S -- New York, N.Y. -- Science. 2010 Feb 19;327(5968):1008-10. doi: 10.1126/science.1182570. Epub 2010 Feb 11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20150447" target="_blank"〉PubMed〈/a〉
    Keywords: *Agriculture ; Cations ; China ; Crops, Agricultural/*growth & development/metabolism ; Fertilizers ; Hydrogen-Ion Concentration ; Nitrogen ; *Soil ; Time Factors
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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    Bulk organic geochemistry of sediments from Puyehue Lake and its watershed (Chile, 40°S) : implications for paleoenvironmental reconstructions (2009)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Palaeogeography, Palaeoclimatology, Palaeoecology 294 (2010): 56-71, doi:10.1016/j.palaeo.2009.03.012.
    Description: Since the last deglaciation, the mid-latitudes of the southern Hemisphere have undergone considerable environmental changes. In order to better understand the response of continental ecosystems to paleoclimate changes in southern South America, we investigated the sedimentary record of Puyehue Lake, located in the western piedmont of the Andes in south-central Chile (40°S). We analyzed the elemental (C, N) and stable isotopic (δ13C, δ15N) composition of the sedimentary organic matter preserved in the lake and its watershed to estimate the relative changes in the sources of sedimentary organic carbon through space and time. The geochemical signature of the aquatic and terrestrial end-members was determined on samples of lake particulate organic matter (N/C: 0.130) and Holocene paleosols (N/C: 0.069), respectively. A simple mixing equation based on the N/C ratio of these end-members was then used to estimate the fraction of terrestrial carbon (ƒT) preserved in the lake sediments. Our approach was validated using surface sediment samples, which show a strong relation between ƒT and distance to the main rivers and to the shore. We further applied this equation to an 11.22 m long sediment core to reconstruct paleoenvironmental changes in Puyehue Lake and its watershed during the last 17.9 kyr. Our data provide evidence for a first warming pulse at 17.3 cal kyr BP, which triggered a rapid increase in lake diatom productivity, lagging the start of a similar increase in sea surface temperature (SST) off Chile by 1500 years. This delay is best explained by the presence of a large glacier in the lake watershed, which delayed the response time of the terrestrial proxies and limited the concomitant expansion of the vegetation in the lake watershed (low ƒT). A second warming pulse at 12.8 cal kyr BP is inferred from an increase in lake productivity and a major expansion of the vegetation in the lake watershed, demonstrating that the Puyehue glacier had considerably retreated from the watershed. This second warming pulse is synchronous with a 2°C increase in SST off the coast of Chile, and its timing corresponds to the beginning of the Younger Dryas Chronozone. These results contribute to the mounting evidence that the climate in the mid-latitudes of the southern Hemisphere was warming during the Younger Dryas Chronozone, in agreement with the bipolar see-saw hypothesis.
    Description: This research was partly supported by the Belgian OSTC project EV/12/10B "A continuous Holocene record of ENSO variability in southern Chile". S.B. is supported by a BAEF fellowship (Belgian American Educational Foundation), and by an EU Marie Curie Outgoing Fellowship under the FP6 programme.
    Keywords: Organic matter ; Lake sediments ; Carbon ; Nitrogen ; Southern Hemisphere ; Deglaciation
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
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