ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Drivers of nitrogen transfer in stream food webs across continents (2017)
    Wiley
    In: Ecology
    Details
    Publication Date: 2017-09-08
    Description: Studies of trophic-level material and energy transfers are central to ecology. The use of isotopic tracers has now made it possible to measure trophic transfer efficiencies of important nutrients and to better understand how these materials move through food webs. We analyzed data from thirteen 15 N-ammonium tracer addition experiments to quantify N transfer from basal resources to animals in headwater streams with varying physical, chemical, and biological features. N transfer efficiencies from primary uptake compartments (PUCs; heterotrophic microorganisms and primary producers) to primary consumers was lower (mean: 11.5%, range: 〈1%-43%) than N transfer efficiencies from primary consumers to predators (mean: 80%, range: 5%- 〉100%). Total N transferred (as a rate) was greater in streams with open compared to closed canopies and overall N transfer efficiency generally followed a similar pattern, although was not statistically significant. We used principal component analysis to condense a suite of site characteristics into two environmental components. Total N uptake rates among trophic levels were best predicted by the component that was correlated with latitude, DIN:SRP, GPP:ER, and % canopy cover. N transfer efficiency did not respond consistently to environmental variables. Our results suggest that canopy cover influences N movement through stream food webs because light availability and primary production facilitate N transfer to higher trophic levels. This article is protected by copyright. All rights reserved.
    Print ISSN: 0012-9658
    Electronic ISSN: 1939-9170
    Topics: Biology
    Published by Wiley on behalf of The Ecological Society of America (ESA).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Sources of and processes controlling CO2 emissions change with the size of streams and rivers (2015)
    Springer Nature
    Details
    Publication Date: 2015-08-28
    Description: Nature Geoscience 8, 696 (2015). doi:10.1038/ngeo2507 Authors: E. R. Hotchkiss, R. O. Hall Jr, R. A. Sponseller, D. Butman, J. Klaminder, H. Laudon, M. Rosvall & J. Karlsson Carbon dioxide (CO2) evasion from streams and rivers to the atmosphere represents a substantial flux in the global carbon cycle. The proportions of CO2 emitted from streams and rivers that come from terrestrially derived CO2 or from CO2 produced within freshwater ecosystems through aquatic metabolism are not well quantified. Here we estimated CO2 emissions from running waters in the contiguous United States, based on freshwater chemical and physical characteristics and modelled gas transfer velocities at 1463 United States Geological Survey monitoring sites. We then assessed CO2 production from aquatic metabolism, compiled from previously published measurements of net ecosystem production from 187 streams and rivers across the contiguous United States. We find that CO2 produced by aquatic metabolism contributes about 28% of CO2 evasion from streams and rivers with flows between 0.0001 and 19,000 m3 s−1. We mathematically modelled CO2 flux from groundwater into running waters along a stream–river continuum to evaluate the relationship between stream size and CO2 source. Terrestrially derived CO2 dominates emissions from small streams, and the percentage of CO2 emissions from aquatic metabolism increases with stream size. We suggest that the relative role of rivers as conduits for terrestrial CO2 efflux and as reactors mineralizing terrestrial organic carbon is a function of their size and connectivity with landscapes.
    Print ISSN: 1752-0894
    Electronic ISSN: 1752-0908
    Topics: Geosciences
    Published by Springer Nature
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Modeling priming effects on microbial consumption of dissolved organic carbon in rivers (2014)
    Wiley
    Details
    Publication Date: 2014-05-02
    Description: Rivers receive and process large quantities of terrestrial dissolved organic carbon (DOC). Biologically available (unstable) DOC leached from primary producers may stimulate (i.e., prime) the consumption of more stable terrestrially-derived DOC by heterotrophic microbes. We measured microbial DOC consumption (i.e., decay rates) from contrasting C sources in ten rivers in the Western and Midwestern United States using short-term bioassays of river water, soil and algal leachates, glucose, and commercial humate. We added inorganic nutrients (ammonium and phosphorus) to a subset of bioassays. We also amended a subset of river, soil, and commercial humate bioassays with glucose or algal leachates to test the hypothesis that unstable DOC primes consumption of more stable DOC. We used prior measurements of source-specific DOC bioavailability, linked with a Bayesian process model, to estimate means and posterior probability distributions for source-specific DOC decay rates in multi-source bioassays. Modeled priming effects ranged from a −130 to +370% change in more stable DOC decay when incubated with unstable DOC. Glucose increased modeled river DOC decay by an average of 87% among all rivers. Glucose and algal leachates increased soil leachate and commercial humate decay by an average of 25% above background rates. Inorganic nutrient additions did not have consistent effects on DOC decay, likely because most of the study rivers had high ambient background nutrients. Our results demonstrate that the priming effect can augment DOC decay in rivers. In addition, Bayesian models can be used to estimate mechanisms driving aquatic ecosystem processes that are difficult to measure directly.
    Print ISSN: 0148-0227
    Topics: Biology , Geosciences
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Enhancement of primary production during drought in a temperate watershed is greater in larger rivers than headwater streams (2019)
    Wiley
    Details
    Publication Date: 2019
    Description: Abstract Drought is common in rivers, yet how this disturbance regulates metabolic activity across network scales is largely unknown. Drought often lowers gross primary production (GPP) and ecosystem respiration (ER) in small headwaters but by contrast can enhance GPP and cause algal blooms in downstream estuaries. We estimated ecosystem metabolism across a nested network of 13 reaches from headwaters to the main stem of the Connecticut River from 2015 through 2017, which encompassed a pronounced drought. During drought, GPP and ER increased, but with greater enhancement in larger rivers. Responses of GPP and ER were partially due to warmer temperatures associated with drought, particularly in the larger rivers where temperatures during summer drought were 〉 10°C higher than typical summer baseflow. The larger rivers also had low canopy cover, which allowed primary producers to take advantage of lower turbidity and fewer cloudy days during drought. We conclude that GPP is enhanced by higher temperature, lower turbidity, and longer water residence times that are all a function of low discharge, but ecosystem response in temperate watersheds to these drivers depends on light availability regulated by riparian canopy cover. In larger rivers, GPP increased more than ER during drought, even leading to temporary autotrophy, an otherwise rare event in the typically light‐limited heterotrophic Connecticut River main stem. With climate change, rivers and streams may become warmer and drought frequency and severity may increase. Such changes may increase autotrophy in rivers with broad implications for carbon cycling and water quality in aquatic ecosystems.
    Print ISSN: 0024-3590
    Electronic ISSN: 1939-5590
    Topics: Biology , Geosciences , Physics
    Published by Wiley on behalf of The Association for the Sciences of Limnology and Oceanography (ASLO).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Stream denitrification across biomes and its response to anthropogenic nitrate loading (2008)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2008-03-14
    Description: Anthropogenic addition of bioavailable nitrogen to the biosphere is increasing and terrestrial ecosystems are becoming increasingly nitrogen-saturated, causing more bioavailable nitrogen to enter groundwater and surface waters. Large-scale nitrogen budgets show that an average of about 20-25 per cent of the nitrogen added to the biosphere is exported from rivers to the ocean or inland basins, indicating that substantial sinks for nitrogen must exist in the landscape. Streams and rivers may themselves be important sinks for bioavailable nitrogen owing to their hydrological connections with terrestrial systems, high rates of biological activity, and streambed sediment environments that favour microbial denitrification. Here we present data from nitrogen stable isotope tracer experiments across 72 streams and 8 regions representing several biomes. We show that total biotic uptake and denitrification of nitrate increase with stream nitrate concentration, but that the efficiency of biotic uptake and denitrification declines as concentration increases, reducing the proportion of in-stream nitrate that is removed from transport. Our data suggest that the total uptake of nitrate is related to ecosystem photosynthesis and that denitrification is related to ecosystem respiration. In addition, we use a stream network model to demonstrate that excess nitrate in streams elicits a disproportionate increase in the fraction of nitrate that is exported to receiving waters and reduces the relative role of small versus large streams as nitrate sinks.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mulholland, Patrick J -- Helton, Ashley M -- Poole, Geoffrey C -- Hall, Robert O -- Hamilton, Stephen K -- Peterson, Bruce J -- Tank, Jennifer L -- Ashkenas, Linda R -- Cooper, Lee W -- Dahm, Clifford N -- Dodds, Walter K -- Findlay, Stuart E G -- Gregory, Stanley V -- Grimm, Nancy B -- Johnson, Sherri L -- McDowell, William H -- Meyer, Judy L -- Valett, H Maurice -- Webster, Jackson R -- Arango, Clay P -- Beaulieu, Jake J -- Bernot, Melody J -- Burgin, Amy J -- Crenshaw, Chelsea L -- Johnson, Laura T -- Niederlehner, B R -- O'Brien, Jonathan M -- Potter, Jody D -- Sheibley, Richard W -- Sobota, Daniel J -- Thomas, Suzanne M -- England -- Nature. 2008 Mar 13;452(7184):202-5. doi: 10.1038/nature06686.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. mulhollandpj@ornl.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18337819" target="_blank"〉PubMed〈/a〉
    Keywords: Agriculture ; Bacteria/metabolism ; Computer Simulation ; *Ecosystem ; Geography ; *Human Activities ; Nitrates/*analysis/*metabolism ; Nitrites/*analysis/*metabolism ; Nitrogen/analysis/metabolism ; Nitrogen Isotopes ; Plants/metabolism ; Rivers/*chemistry ; Urbanization
    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)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Loss of a harvested fish species disrupts carbon flow in a diverse tropical river (2006)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2006-08-12
    Description: Harvesting threatens many vertebrate species, yet few whole-system manipulations have been conducted to predict the consequences of vertebrate losses on ecosystem function. Here, we show that a harvested migratory detrital-feeding fish (Prochilodontidae: Prochilodus mariae) modulates carbon flow and ecosystem metabolism. Natural declines in and experimental removal of Prochilodus decreased downstream transport of organic carbon and increased primary production and respiration. Thus, besides its economic value, Prochilodus is a critical ecological component of South American rivers. Lack of functional redundancy for this species highlights the importance of individual species and, contrary to theory, suggests that losing one species from lower trophic levels can affect ecosystem functioning even in species-rich ecosystems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Taylor, Brad W -- Flecker, Alexander S -- Hall, Robert O Jr -- New York, N.Y. -- Science. 2006 Aug 11;313(5788):833-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA. brad.taylor@dartmouth.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16902137" target="_blank"〉PubMed〈/a〉
    Keywords: Animal Migration ; Animals ; Biofilms ; Biomass ; Body Size ; Carbon/*metabolism ; Conservation of Natural Resources ; *Ecosystem ; Feeding Behavior ; *Fisheries ; Fishes/anatomy & histology/*physiology ; Food Chain ; Population Dynamics ; *Rivers ; Seasons ; South America ; Tropical Climate
    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)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    A coupled metabolic-hydraulic model and calibration scheme for estimating whole-river metabolism during dynamic flow conditions (2017)
    Wiley
    Details
    Publication Date: 2017-09-29
    Description: Conventional methods for estimating whole-stream metabolic rates from measured dissolved oxygen dynamics do not account for the variation in solute transport times created by dynamic flow conditions. Changes in flow at hourly time scales are common downstream of hydroelectric dams (i.e., hydropeaking), and hydrologic limitations of conventional metabolic models have resulted in a poor understanding of the controls on biological production in these highly managed river ecosystems. To overcome these limitations, we coupled a two-station metabolic model of dissolved oxygen dynamics with a hydrologic river routing model. We designed calibration and parameter estimation tools to infer values for hydrologic and metabolic parameters based on time series of water quality data, achieving the ultimate goal of estimating whole-river gross primary production and ecosystem respiration during dynamic flow conditions. Our case study data for model design and calibration were collected in the tailwater of Glen Canyon Dam (Arizona, U.S.A.), a large hydropower facility where the mean discharge was 325 m 3 s −1 and the average daily coefficient of variation of flow was 0.17 (i.e., the hydropeaking index averaged from 2006 to 2016). We demonstrate the coupled model's conceptual consistency with conventional models during steady flow conditions, and illustrate the potential bias in metabolism estimates with conventional models during unsteady flow conditions. This effort contributes an approach to solute transport modeling and parameter estimation that allows study of whole-ecosystem metabolic regimes across a more diverse range of hydrologic conditions commonly encountered in streams and rivers.
    Electronic ISSN: 1541-5856
    Topics: Biology , Geosciences
    Published by Wiley on behalf of The Association for the Sciences of Limnology and Oceanography (ASLO).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    The metabolic regimes of flowing waters (2017)
    Wiley
    Details
    Publication Date: 2017-10-13
    Description: The processes and biomass that characterize any ecosystem are fundamentally constrained by the total amount of energy that is either fixed within or delivered across its boundaries. Ultimately, ecosystems may be understood and classified by their rates of total and net productivity and by the seasonal patterns of photosynthesis and respiration. Such understanding is well developed for terrestrial and lentic ecosystems but our understanding of ecosystem phenology has lagged well behind for rivers. The proliferation of reliable and inexpensive sensors for monitoring dissolved oxygen and carbon dioxide is underpinning a revolution in our understanding of the ecosystem energetics of rivers. Here, we synthesize our current understanding of the drivers and constraints on river metabolism, and set out a research agenda aimed at characterizing, classifying and modeling the current and future metabolic regimes of flowing waters.
    Print ISSN: 0024-3590
    Electronic ISSN: 1939-5590
    Topics: Biology , Geosciences , Physics
    Published by Wiley on behalf of The Association for the Sciences of Limnology and Oceanography (ASLO).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    Electronic Resource
    Electronic Resource
    Spontaneous Super-Contraction of Animal Hair (1935)
    [s.l.] : Nature Publishing Group
    Nature 136 (1935), S. 28-29 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SUPER-CONTRACTION induced in silk fibres by acid, and in wool by means of steam and chemical reagents, has been described by Farrell1, Astbury and Woods2 and Speakman3 respectively. I have recently obtained evidence of super-contraction in the guard ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/136028b0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    ‘Lines’ on the Surface of Moving Water (1936)
    [s.l.] : Nature Publishing Group
    Nature 138 (1936), S. 466-466 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SINCE reading the interesting accounts of this phenomenon by Prof. W. Schmidt1 and Prof. H. Stansfield2, I have noticed several striking instances which yield a clue to their cause. They occurred on the surfaces of clear country streams bridged by planks that ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/138466a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...