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  • Artikel  (66)
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  • 1
    Publikationsdatum: 2022-10-27
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pold, G., Baillargeon, N., Lepe, A., Rastetter, E. B., & Sistla, S. A. Warming effects on arctic tundra biogeochemistry are limited but habitat-dependent: a meta-analysis. Ecosphere, 12(10), (2021): e03777, https://doi.org/10.1002/ecs2.3777.
    Beschreibung: Arctic tundra consists of diverse habitats that differ in dominant vegetation, soil moisture regimes, and relative importance of organic vs. inorganic nutrient cycling. The Arctic is also the most rapidly warming global area, with winter warming dominating. This warming is expected to have dramatic effects on tundra carbon and nutrient dynamics. We completed a meta-analysis of 166 experimental warming study papers to evaluate the hypotheses that warming changes tundra biogeochemical cycles in a habitat- and seasonally specific manner and that the carbon (C), nitrogen (N), and phosphorus (P) cycles will be differentially accelerated, leading to decoupling of elemental cycles. We found that nutrient availability and plant leaf stoichiometry responses to experimental warming were variable and overall weak, but that both gross primary productivity and the plant C pool tended to increase with growing season warming. The effects of winter warming on C fluxes did not extend into the growing season. Overall, although warming led to more consistent increases in C fluxes compared to N or P fluxes, evidence for decoupling of biogeochemical cycles is weak and any effect appears limited to heath habitats. However, data on many habitats are too sparse to be able to generalize how warming might decouple biogeochemical cycles, and too few year-round warming studies exist to ascertain whether the season under which warming occurs alters how ecosystems respond to warming. Coordinated field campaigns are necessary to more robustly document tundra habitat-specific responses to realistic climate warming scenarios in order to better understand the mechanisms driving this heterogeneity and identify the tundra habitats, communities, and soil pools most susceptible to warming.
    Beschreibung: Funding for this project was provided by NSF Signals in the Soil grant number 1841610 to SAS and ER. SAS and ER conceived of and acquired funding for the project. NB completed the literature search.
    Schlagwort(e): Arctic ; Biogeochemistry ; Climate change ; Experimental warming ; Meta-analysis ; Stoichiometry ; Tundra
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 2
    Publikationsdatum: 2022-10-27
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Stunz, E., Fetcher, N., Lavretsky, P., Mohl, J., Tang, J., & Moody, M. Landscape genomics provides evidence of ecotypic adaptation and a barrier to gene flow at treeline for the arctic foundation species Eriophorum vaginatum. Frontiers in Plant Science, 13, (2022): 860439, https://doi.org/10.3389/fpls.2022.860439.
    Beschreibung: Global climate change has resulted in geographic range shifts of flora and fauna at a global scale. Extreme environments, like the Arctic, are seeing some of the most pronounced changes. This region covers 14% of the Earth’s land area, and while many arctic species are widespread, understanding ecotypic variation at the genomic level will be important for elucidating how range shifts will affect ecological processes. Tussock cottongrass (Eriophorum vaginatum L.) is a foundation species of the moist acidic tundra, whose potential decline due to competition from shrubs may affect ecosystem stability in the Arctic. We used double-digest Restriction Site-Associated DNA sequencing to identify genomic variation in 273 individuals of E. vaginatum from 17 sites along a latitudinal gradient in north central Alaska. These sites have been part of 30 + years of ecological research and are inclusive of a region that was part of the Beringian refugium. The data analyses included genomic population structure, demographic models, and genotype by environment association. Genome-wide SNP investigation revealed environmentally associated variation and population structure across the sampled range of E. vaginatum, including a genetic break between populations north and south of treeline. This structure is likely the result of subrefugial isolation, contemporary isolation by resistance, and adaptation. Forty-five candidate loci were identified with genotype-environment association (GEA) analyses, with most identified genes related to abiotic stress. Our results support a hypothesis of limited gene flow based on spatial and environmental factors for E. vaginatum, which in combination with life history traits could limit range expansion of southern ecotypes northward as the tundra warms. This has implications for lower competitive attributes of northern plants of this foundation species likely resulting in changes in ecosystem productivity.
    Beschreibung: This research was made possible by funding provided by NSF/PLR-1417645 to MM. The Botanical Society of America Graduate Student Research Award and the Dodson Research Grant from the Graduate School of the University of Texas at El Paso provided assistance to ES. The grant 5U54MD007592 from the National Institute on Minority Health and Health Disparities (NIMHD), a component of the National Institutes of Health (NIH) provided bioinformatics resources and support of JM.
    Schlagwort(e): Arctic ; Climate change ; Eriophorum vaginatum ; Landscape genomics ; Environmental niche modeling ; Genotype-environment association analyses ; Refugia
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 3
    Publikationsdatum: 2022-10-27
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rastetter, E., Kwiatkowski, B., Kicklighter, D., Plotkin, A., Genet, H., Nippert, J., O’Keefe, K., Perakis, S., Porder, S., Roley, S., Ruess, R., Thompson, J., Wieder, W., Wilcox, K., & Yanai, R. N and P constrain C in ecosystems under climate change: role of nutrient redistribution, accumulation, and stoichiometry. Ecological Applications, (2022): e2684, https://doi.org/10.1002/eap.2684.
    Beschreibung: We use the Multiple Element Limitation (MEL) model to examine responses of 12 ecosystems to elevated carbon dioxide (CO2), warming, and 20% decreases or increases in precipitation. Ecosystems respond synergistically to elevated CO2, warming, and decreased precipitation combined because higher water-use efficiency with elevated CO2 and higher fertility with warming compensate for responses to drought. Response to elevated CO2, warming, and increased precipitation combined is additive. We analyze changes in ecosystem carbon (C) based on four nitrogen (N) and four phosphorus (P) attribution factors: (1) changes in total ecosystem N and P, (2) changes in N and P distribution between vegetation and soil, (3) changes in vegetation C:N and C:P ratios, and (4) changes in soil C:N and C:P ratios. In the combined CO2 and climate change simulations, all ecosystems gain C. The contributions of these four attribution factors to changes in ecosystem C storage varies among ecosystems because of differences in the initial distributions of N and P between vegetation and soil and the openness of the ecosystem N and P cycles. The net transfer of N and P from soil to vegetation dominates the C response of forests. For tundra and grasslands, the C gain is also associated with increased soil C:N and C:P. In ecosystems with symbiotic N fixation, C gains resulted from N accumulation. Because of differences in N versus P cycle openness and the distribution of organic matter between vegetation and soil, changes in the N and P attribution factors do not always parallel one another. Differences among ecosystems in C-nutrient interactions and the amount of woody biomass interact to shape ecosystem C sequestration under simulated global change. We suggest that future studies quantify the openness of the N and P cycles and changes in the distribution of C, N, and P among ecosystem components, which currently limit understanding of nutrient effects on C sequestration and responses to elevated CO2 and climate change.
    Beschreibung: This material is based on work supported by the National Science Foundation under Grant No. 1651722 as well through the NSF LTER Program 1637459, 2220863 (ARC), 1637686 (NWT), 1832042 (KBS), 2025849 (KNZ), 1636476 (BNZ), 1637685 (HBR), 1832210 (HFR), 2025755 (AND). We also acknowledge NSF grants 1637653 and 1754126 (INCyTE RCN), and DOE grant DESC0019037. We also acknowledge support through the USDA Forest Service Hubbard Brook Experimental Forest, North Woodstock, New Hampshie (USDA NIFA 2019-67019-29464) and Pacific Northwest Research Station, Corvallis, Oregon.
    Schlagwort(e): Carbon dioxide fertilization ; Carbon sequestration ; Carbon-nitrogen interactions ; Carbon-phosphorus interactions ; Climate change ; Long-term ecological research (LTER) ; Nitrogen cycle ; Phosphorus cycle ; Terrestrial ecosystem stoichiometry
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 4
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Symbiodiniaceae communities in corals with ITS-2 rDNA amplicon sequencing
    Beschreibung: Symbiodiniaceae communities were investigated at three locations on the Great Barrier Reef in October 2014. Acropora millepora samples from Davies Reef lagoon (18°30′3.96′′S, 147°22′48′′E), Rib Reef (18°28′53.4′′S, 146°52′24.96′′E), and Pandora Island (18°48′45′′S, 146°25′59.16′′E), were exposed to various stressors including pCO2, heat, bacteria, all of these, or none of these (control). This dataset lists accessions and collection information for ITS-2 rDNA amplicon data that are available at the National Center for Biotechnology Information (NCBI) under BioProject PRJNA596498. 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/844431
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1635798
    Schlagwort(e): Acropora millepora ; Alpha diversity ; Beta diversity ; Climate change ; Coral ; Symbiodiniaceae
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
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  • 5
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    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Experimental coral treatments
    Beschreibung: Coral samples from reefs in Mo'orea, French Polynesia were exposed to various experimental treatments to quantify how different environmental stressors impact the coral health and microbial community structure of the corals. Environmental stressors included increased temperature and nutrients as well as exudate released from corals when they bleach. 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/843188
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1635798, NSF Division of Ocean Sciences (NSF OCE) OCE-1635913
    Schlagwort(e): Coral reef ; Holobiont ; Coral microbiome ; Climate change
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
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  • 6
    Publikationsdatum: 2022-10-27
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Winters, G., Teichberg, M., Reuter, H., Viana, I. G., & Willette, D. A. Editorial: seagrasses under times of change. Frontiers in Plant Science, 13, (2022): 870478, https://doi.org/10.3389/fpls.2022.870478.
    Beschreibung: Awareness of the ecological importance of seagrasses is growing due to recent attention to their role in carbon sequestration as a potential blue carbon sink (Fourqurean et al., 2012; Bedulli et al.), as well as their role in nutrient cycling (Romero et al., 2006), sediment stabilization (James et al., 2019), pathogen filtration (Lamb et al., 2017), and the formation of essential habitats for economically important marine species (Jackson et al., 2001; Jones et al.). Despite their importance and the increasing public and scientific awareness of seagrasses, simultaneous global (e.g., ocean warming, increase in frequency and severity of extreme events, introduction and spread of invasive species) and local (e.g., physical disturbances, eutrophication, and sedimentation) anthropogenic stressors continue to be the main causes behind the ongoing global decline of seagrass meadows (Orth et al., 2006; Waycott et al., 2009).
    Beschreibung: This research was partially funded through the BMBF project SEANARIOS (Seagrass scenarios under thermal and nutrient stress: FKZ 03F0826A) to HR and MT. MT was partially funded through the DFG project SEAMAC (Seagrass and macroalgal community dynamics and performance under environmental change; TE 1046/3-1). IV was supported by a postdoctoral research grant Juan de la Cierva-Incorporación (IJC2019-040554-I) and from MCIN/AEI /10.13039/501100011033 (Spain).
    Schlagwort(e): Seagrasses ; Climate change ; Eutrophication ; Responses of seagrasses to single and combined stressors ; Spatial-temporal modeling
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 7
    Publikationsdatum: 2022-10-27
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chavarry, J. M., Law, K. L., Barton, A. D., Bowlin, N. M., Ohman, M. D., & Choy, C. A. Relative exposure to microplastics and prey for a pelagic forage fish. Environmental Research Letters, 17(6), (2022): 064038, https://doi.org/10.1088/1748-9326/ac7060.
    Beschreibung: In the global ocean, more than 380 species are known to ingest microplastics (plastic particles less than 5 mm in size), including mid-trophic forage fishes central to pelagic food webs. Trophic pathways that bioaccumulate microplastics in marine food webs remain unclear. We assess the potential for the trophic transfer of microplastics through forage fishes, which are prey for diverse predators including commercial and protected species. Here, we quantify Northern Anchovy (Engraulis mordax) exposure to microplastics relative to their natural zooplankton prey, across their vertical habitat. Microplastic and zooplankton samples were collected from the California Current Ecosystem in 2006 and 2007. We estimated the abundance of microplastics beyond the sampled size range but within anchovy feeding size ranges using global microplastic size distributions. Depth-integrated microplastics (0–30 m depth) were estimated using a depth decay model, accounting for the effects of wind-driven vertical mixing on buoyant microplastics. In this coastal upwelling biome, the median relative exposure for an anchovy that consumed prey 0.287–5 mm in size was 1 microplastic particle for every 3399 zooplankton individuals. Microplastic exposure varied, peaking within offshore habitats, during the winter, and during the day. Maximum exposure to microplastic particles relative to zooplankton prey was higher for juvenile (1:23) than adult (1:33) anchovy due to growth-associated differences in anchovy feeding. Overall, microplastic particles constituted fewer than 5% of prey-sized items available to anchovy. Microplastic exposure is likely to increase for forage fishes in the global ocean alongside declines in primary productivity, and with increased water column stratification and microplastic pollution.
    Beschreibung: This work originated from the Plastic Awareness Global Initiative (PAGI) international workshop, hosted by the Center for Marine Biodiversity and Conservation (CMBC) at Scripps Institution of Oceanography at the University of California San Diego in 2018, with support from Igor Korneitchouk and the Wilsdorf Mettler Future Foundation. We thank the workshop participants for early discussions and a collaborative meeting space. We thank Kelly Lance for her illustration contributions, and the SIO Communications Office for their support. We thank Miriam Doyle and Ryan Rykaczewski for their assistance in data acquisition, and we thank Penny Dockry and Stuart Sandin of CMBC for administrative and logistical support. Julia Chavarry was supported by the San Diego Fellowship. This paper is a contribution from the California Current Ecosystem Long Term Ecological Research site, supported by the National Science Foundation.
    Schlagwort(e): Upwelling ecosystems ; Food webs ; Climate change ; Engraulis mordax
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 8
    Publikationsdatum: 2022-10-18
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pold, G., Kwiatkowski, B. L., Rastetter, E. B., & Sistla, S. A. Sporadic P limitation constrains microbial growth and facilitates SOM accumulation in the stoichiometrically coupled, acclimating microbe-plant-soil model. Soil Biology & Biochemistry, 165, (2022): 108489, https://doi.org/10.1016/j.soilbio.2021.108489.
    Beschreibung: Requirements for biomass carbon (C), nitrogen (N), and phosphorus (P) constrain organism growth and are important agents for structuring ecosystems. Arctic tundra habitats are strongly nutrient limited as decomposition and recycling of nutrients are slowed by low temperature. Modeling interactions among these elemental cycles affords an opportunity to explore how disturbances such as climate change might differentially affect these nutrient cycles. Here we introduce a C–N–P-coupled version of the Stoichiometrically Coupled Acclimating Microbe-Plant-Soil (SCAMPS) model, “SCAMPS-CNP”, and a corresponding modified CN-only model, “SCAMPS-CN”. We compared how SCAMPS-CNP and the modified SCAMPS-CN models project a moderate (RCP 6.0) air warming scenario will impact tussock tundra nutrient availability and ecosystem C stocks. SCAMPS-CNP was characterized by larger SOM and smaller organism C stocks compared to SCAMPS-CN, and a greater reduction in ecosystem C stocks under warming. This difference can largely be attributed to a smaller microbial biomass in the CNP model, which, instead of being driven by direct costs of P acquisition, was driven by variable resource limitation due to asynchronous C, N, and P availability and demand. Warming facilitated a greater relative increase in plant and microbial biomass in SCAMPS-CNP, however, facilitated by increased extracellular enzyme pools and activity, which more than offset the metabolic costs associated with their production. Although the microbial community was able to flexibly adapt its stoichiometry and become more bacteria-like (N-rich) in both models, its stoichiometry deviated further from its target value in the CNP model because of the need to balance cellular NP ratio. Our results indicate that seasonality and asynchrony in resources affect predicted changes in ecosystem C storage under warming in these models, and therefore build on a growing body of literature indicating stoichiometry should be considered in carbon cycling projections.
    Beschreibung: This work was funded by the National Science Foundation Signals in the Soil grant number 1841610 to SAS and EBR.
    Schlagwort(e): Stoichiometry ; Modeling ; Microbial physiology ; Tundra ; Climate change
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 9
    Publikationsdatum: 2022-05-27
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Burnham, K. A., Nowicki, R. J., Hall, E. R., Pi, J., & Page, H. N. Effects of ocean acidification on the performance and interaction of fleshy macroalgae and a grazing sea urchin. Journal of Experimental Marine Biology and Ecology, 547, (2022): 151662, https://doi.org/10.1016/j.jembe.2021.151662.
    Beschreibung: When predicting the response of marine ecosystems to climate change, it is increasingly recognized that understanding the indirect effects of ocean acidification on trophic interactions is as important as studying direct effects on organism physiology. Furthermore, comprehensive studies that examine these effects simultaneously are needed to identify and link the underlying mechanisms driving changes in species interactions. Using an onshore ocean acidification simulator system, we investigated the direct and indirect effects of elevated seawater pCO2 on the physiology and trophic interaction of fleshy macroalgae and the grazing sea urchin Lytechinus variegatus. Macroalgal (Dictyota spp.) biomass increased despite decreased photosynthetic rates after two-week exposure to elevated pCO2. Algal tissue carbon content remained constant, suggesting the use of alternative carbon acquisition pathways beneficial to growth under acidification. Higher C:N ratios driven by a slight reduction in N content in algae exposed to elevated pCO2 suggest a decrease in nutritional content under acidification. Urchin (L. variegatus) respiration, biomass, and righting time did not change significantly after six-week exposure to elevated pCO2, indicating that physiological stress and changes in metabolism are not mechanisms through which the trophic interaction was impacted. Correspondingly, urchin consumption rates of untreated macroalgae (Caulerpa racemosa) were not significantly affected by pCO2. In contrast, exposure of urchins to elevated pCO2 significantly reduced the number of correct foraging choices for ambient macroalgae (Dictyota spp.), indicating impairment of urchin chemical sensing under acidification. However, exposure of algae to elevated pCO2 returned the number of correct foraging choices in similarly exposed urchins to ambient levels, suggesting alongside higher C:N ratios that algal nutritional content was altered in a way detectable by the urchins under acidification. These results highlight the importance of studying the indirect effects of acidification on trophic interactions simultaneously with direct effects on physiology. Together, these results suggest that changes to urchin chemical sensing and algal nutritional quality are the driving mechanisms behind surprisingly unaltered urchin foraging behavior for fleshy macroalgae under joint exposure to ocean acidification. Consistent foraging behavior and consumption rates suggest that the trophic interaction between L. variegatus and fleshy macroalgae may be sustained under future acidification. However, increases in fleshy macroalgal biomass driven by opportunistic carbon acquisition strategies have the potential to cause ecological change, depending on how grazer populations respond. Additional field research is needed to determine the outcome of these results over time and under a wider range of environmental conditions.
    Beschreibung: This work was supported by Mote Marine Laboratory Postdoctoral Fellowships (RJN and HNP), Becker Internship Funding, and philanthropic funds to ERH.
    Schlagwort(e): Climate change ; Elevated pCO2 ; Direct effects ; Physiology ; Indirect effects ; Herbivory
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 10
    Publikationsdatum: 2022-10-05
    Beschreibung: Este documento de trabajo examina los vínculos entre el aprendizaje de la alfabetización, el desarrollo de competencias y el mundo del trabajo, en línea con el tema del Día Internacional de la Alfabetización (ILD, por sus siglas en inglés) 2018. Su objetivo es identificar acciones de política que ayudan a integrar el aprendizaje de la alfabetización y el desarrollo de competencias, con el objetivo de apoyar las vías hacia el empleo.
    Beschreibung: OPENASFA INPUT Documento de trabajo preparado para la Conferencia Internacional sobre “Alfabetización y desarrollo de competencias” (París, 7 de septiembre de 2018)
    Beschreibung: Published
    Beschreibung: Not Known
    Schlagwort(e): Desarrollo de competencias ; Alfabetización ; Educación ; Desempleo ; Igualdad de género
    Repository-Name: AquaDocs
    Materialart: Report
    Format: 20pp.
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  • 11
    Publikationsdatum: 2022-06-06
    Beschreibung: Author Posting. © American Meteorological Society, 2021. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Applied Meteorology and Climatology 60(9), (2021): 1361–1370, https://doi.org/10.1175/JAMC-D-20-0254.1.
    Beschreibung: We analyze how winter thaw events (TE; T 〉 0°C) are changing on the summit of Mount Washington, New Hampshire, using three metrics: the number of TE, number of thaw hours, and number of thaw degree-hours for temperature and dewpoint for winters from 1935/36 to 2019/20. The impact of temperature-only TE and dewpoint TE on snow depth are compared to quantify the different impacts of sensible-only heating and sensible-and-latent heating, respectively. Results reveal that temperature and dewpoint TE for all metrics increased at a statistically significant rate (p 〈 0.05) over the full time periods studied for temperature (1935/36–2019/20) and dewpoint (1939/40–2019/20). Notably, around 2000/01, the positive trends increased for most variables, including dewpoint-thaw degree-hours that increased by 82.11 degree-hours decade−1 during 2000–20, which is approximately 5 times as faster as the 1939–2020 rate of 17.70 degree-hours decade−1. Furthermore, a clear upward shift occurred around 1990 in the lowest winter values of thaw hours and thaw degree-hours—winters now have a higher baseline amount of thaw than before 1990. Snow-depth loss during dewpoint TE (0.36 cm h−1) occurred more than 2 times as fast as temperature-only TE (0.14 cm h−1). With winters projected to warm throughout the twenty-first century in the northeastern United States, it is expected that the trends in winter thaw events, and the sensible and latent energy that they bring, will continue to rise and lead to more frequent winter flooding, fewer days of good quality snow for winter recreation, and changes in ecosystem function.
    Schlagwort(e): Atmosphere ; Snowmelt/icemelt ; Snowpack ; Winter/cool season ; Climate change ; Humidity ; Latent heating/cooling ; Snow cover ; Temperature
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 12
    Publikationsdatum: 2022-07-20
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Clark, S., Hubbard, K., Ralston, D., McGillicuddy, D., Stock, C., Alexander, M., & Curchitser, E. Projected effects of climate change on Pseudo-nitzschia bloom dynamics in the Gulf of Maine. Journal of Marine Systems, 230, (2022): 103737, https://doi.org/10.1016/j.jmarsys.2022.103737.
    Beschreibung: Worldwide, warming ocean temperatures have contributed to extreme harmful algal bloom events and shifts in phytoplankton species composition. In 2016 in the Gulf of Maine (GOM), an unprecedented Pseudo-nitzschia bloom led to the first domoic-acid induced shellfishery closures in the region. Potential links between climate change, warming temperatures, and the GOM Pseudo-nitzschia assemblage, however, remain unexplored. In this study, a global climate change projection previously downscaled to 7-km resolution for the Northwest Atlantic was further refined with a 1–3-km resolution simulation of the GOM to investigate the effects of climate change on HAB dynamics. A 25-year time slice of projected conditions at the end of the 21st century (2073–2097) was compared to a 25-year hindcast of contemporary ocean conditions (1994–2018) and analyzed for changes to GOM inflows, transport, and Pseudo-nitzschia australis growth potential. On average, climate change is predicted to lead to increased temperatures, decreased salinity, and increased stratification in the GOM, with the largest changes occurring in the late summer. Inflows from the Scotian Shelf are projected to increase, and alongshore transport in the Eastern Maine Coastal Current is projected to intensify. Increasing ocean temperatures will likely make P. australis growth conditions less favorable in the southern and western GOM but improve P. australis growth conditions in the eastern GOM, including a later growing season in the fall, and a longer growing season in the spring. Combined, these changes suggest that P. australis blooms in the eastern GOM could intensify in the 21st century, and that the overall Pseudo-nitzschia species assemblage might shift to warmer-adapted species such as P. plurisecta or other Pseudo-nitzschia species that may be introduced.
    Beschreibung: This research was funded by the National Science Foundation (Grant Number OCE-1840381), the National Institute of Environmental Health Sciences (Grant Number 1P01ES028938), the Woods Hole Center for Oceans and Human Health, and the Academic Programs Office of the Woods Hole Oceanographic Institution.
    Schlagwort(e): Gulf of Maine ; ROMS ; Pseudo-nitzschia ; Climate change ; Harmful algal blooms
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 13
    Publikationsdatum: 2022-12-23
    Beschreibung: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 49(12), (2022): e2021GL097598, https://doi.org/10.1029/2021GL097598.
    Beschreibung: The ocean is inhomogeneous in hydrographic properties with diverse water masses. Yet, how this inhomogeneity has evolved in a rapidly changing climate has not been investigated. Using multiple observational and reanalysis datasets, we show that the spatial standard deviation (SSD) of the global ocean has increased by 1.4 ± 0.1% in temperature and 1.5 ± 0.1% in salinity since 1960. A newly defined thermohaline inhomogeneity index, a holistic measure of both temperature and salinity changes, has increased by 2.4 ± 0.1%. Climate model simulations suggest that the observed ocean inhomogeneity increase is dominated by anthropogenic forcing and projected to accelerate by 200%–300% during 2015–2100. Geographically, the rapid upper-ocean warming at mid-to-low latitudes dominates the temperature inhomogeneity increase, while the increasing salinity inhomogeneity is mainly due to the amplified salinity contrast between the subtropical and subpolar latitudes.
    Beschreibung: This work is supported by the Strategic Priority Research Program of Chinese Academy of Sciences (grant XDB42000000 and XDB40000000), the National Key R&D Program of China (2017YFA0603200), and the Shandong Provincial Natural Science Foundation (ZR2020JQ17), and the U.S. National Science Foundation Physical Oceanography Program (OCE- 2048336).
    Beschreibung: 2022-12-23
    Schlagwort(e): Global ocean ; Temperature ; Salinity ; Spatial inhomogeneity ; Climate change
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 14
    Publikationsdatum: 2022-05-26
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pirotta, E., Thomas, L., Costa, D., Hall, A., Harris, C., Harwood, J., Kraus, S., Miller, P., Moore, M., Photopoulou, T., Rolland, R., Schwacke, L., Simmons, S., Southall, B., & Tyack, P. Understanding the combined effects of multiple stressors: a new perspective on a longstanding challenge. Science of The Total Environment, 821, (2022): 153322, https://doi.org/10.1016/j.scitotenv.2022.153322.
    Beschreibung: Wildlife populations and their habitats are exposed to an expanding diversity and intensity of stressors caused by human activities, within the broader context of natural processes and increasing pressure from climate change. Estimating how these multiple stressors affect individuals, populations, and ecosystems is thus of growing importance. However, their combined effects often cannot be predicted reliably from the individual effects of each stressor, and we lack the mechanistic understanding and analytical tools to predict their joint outcomes. We review the science of multiple stressors and present a conceptual framework that captures and reconciles the variety of existing approaches for assessing combined effects. Specifically, we show that all approaches lie along a spectrum, reflecting increasing assumptions about the mechanisms that regulate the action of single stressors and their combined effects. An emphasis on mechanisms improves analytical precision and predictive power but could introduce bias if the underlying assumptions are incorrect. A purely empirical approach has less risk of bias but requires adequate data on the effects of the full range of anticipated combinations of stressor types and magnitudes. We illustrate how this spectrum can be formalised into specific analytical methods, using an example of North Atlantic right whales feeding on limited prey resources while simultaneously being affected by entanglement in fishing gear. In practice, case-specific management needs and data availability will guide the exploration of the stressor combinations of interest and the selection of a suitable trade-off between precision and bias. We argue that the primary goal for adaptive management should be to identify the most practical and effective ways to remove or reduce specific combinations of stressors, bringing the risk of adverse impacts on populations and ecosystems below acceptable thresholds.
    Beschreibung: This work was supported by the Office of Naval Research [grant numbers N000142012697, N000142112096]; and the Strategic Environmental Research and Development Program [grant numbers RC20-1097, RC20-7188, RC21-3091].
    Schlagwort(e): Adaptive management ; Climate change ; Combined effects ; Mechanistic modelling ; Multiple stressors ; Population consequences
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  • 15
    Publikationsdatum: 2022-12-01
    Beschreibung: Author Posting. © American Meteorological Society, 2022. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 103(6), (2022): E1502-E1521, https://doi.org/10.1175/bams-d-21-0227.1.
    Beschreibung: Climate observations inform about the past and present state of the climate system. They underpin climate science, feed into policies for adaptation and mitigation, and increase awareness of the impacts of climate change. The Global Climate Observing System (GCOS), a body of the World Meteorological Organization (WMO), assesses the maturity of the required observing system and gives guidance for its development. The Essential Climate Variables (ECVs) are central to GCOS, and the global community must monitor them with the highest standards in the form of Climate Data Records (CDR). Today, a single ECV—the sea ice ECV—encapsulates all aspects of the sea ice environment. In the early 1990s it was a single variable (sea ice concentration) but is today an umbrella for four variables (adding thickness, edge/extent, and drift). In this contribution, we argue that GCOS should from now on consider a set of seven ECVs (sea ice concentration, thickness, snow depth, surface temperature, surface albedo, age, and drift). These seven ECVs are critical and cost effective to monitor with existing satellite Earth observation capability. We advise against placing these new variables under the umbrella of the single sea ice ECV. To start a set of distinct ECVs is indeed critical to avoid adding to the suboptimal situation we experience today and to reconcile the sea ice variables with the practice in other ECV domains.
    Beschreibung: PH’s contribution was funded under the Australian Government’s Antarctic Science Collaboration Initiative program, and contributes to Project 6 of the Australian Antarctic Program Partnership (ASCI000002). PH acknowledges support through the Australian Antarctic Science Projects 4496 and 4506, and the International Space Science Institute (Bern, Switzerland) project #405.
    Beschreibung: 2022-12-01
    Schlagwort(e): Sea ice ; Climate change ; Climatology ; Climate records
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  • 16
    Publikationsdatum: 2022-10-26
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Owens, W., Zilberman, N., Johnson, K., Claustre, H., Scanderbeg, M., Wijffels, S., & Suga, T. OneArgo: a new paradigm for observing the global ocean. Marine Technology Society Journal, 56(3), (2022): 84–90, https://doi.org/10.4031/MTSJ.56.3.8.
    Beschreibung: OneArgo is a major expansion of the Argo program, which has provided two decades of transformative physical data for the upper 2 km of the global ocean. The present Argo array will be expanded in three ways: (1) Global Core: the existing upper ocean measurements will be extended to high latitudes and marginal seas and with enhanced coverage in the tropics and western boundaries of the major ocean basins; (2) Deep: deep ocean measurements will be obtained for the 50% of the global oceans that are below 2,000-m depth; and (3) Biogeochemical: dissolved oxygen, pH, nitrate, chlorophyll, optical backscatter, and irradiance data will be collected to investigate biogeochemical variability of the upper ocean and the processes by which these cycles respond to a changing climate. The technology and infrastructure necessary for this expansion is now being developed through large-scale regional pilots to further refine the floats and sensors and to demonstrate the utility of these measurements. Further innovation is expected to improve the performance of the floats and sensors and to develop the analyses necessary to provide research-quality data. A fully global OneArgo should be operational within 5–10 years.
    Beschreibung: In the United States, the National Science Foundation–funded Global Ocean Biogeochemistry Array (GO-BGC; https://go-bgc.org).
    Schlagwort(e): Argo floats ; Argo sensors ; OneArgo ; Climate change ; Biogeochemical measurements
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  • 17
    Publikationsdatum: 2022-10-26
    Beschreibung: Author Posting. © American Geophysical Union, 2022. 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 36(1), (2022): e2021GB007113, https://doi.org/10.1029/2021GB007113.
    Beschreibung: Stordalen Mire is a peatland in the discontinuous permafrost zone in arctic Sweden that exhibits a habitat gradient from permafrost palsa, to Sphagnum bog underlain by permafrost, to Eriophorum-dominated fully thawed fen. We used three independent approaches to evaluate the annual, multi-decadal, and millennial apparent carbon accumulation rates (aCAR) across this gradient: seven years of direct semi-continuous measurement of CO2 and CH4 exchange, and 21 core profiles for 210Pb and 14C peat dating. Year-round chamber measurements indicated net carbon balance of −13 ± 8, −49 ± 15, and −91 ± 43 g C m−2 y−1 for the years 2012–2018 in palsa, bog, and fen, respectively. Methane emission offset 2%, 7%, and 17% of the CO2 uptake rate across this gradient. Recent aCAR indicates higher C accumulation rates in surface peats in the palsa and bog compared to current CO2 fluxes, but these assessments are more similar in the fen. aCAR increased from low millennial-scale levels (17–29 g C m−2 y−1) to moderate aCAR of the past century (72–81 g C m−2 y−1) to higher recent aCAR of 90–147 g C m−2 y−1. Recent permafrost collapse, greater inundation and vegetation response has made the landscape a stronger CO2 sink, but this CO2 sink is increasingly offset by rising CH4 emissions, dominated by modern carbon as determined by 14C. The higher CH4 emissions result in higher net CO2-equivalent emissions, indicating that radiative forcing of this mire and similar permafrost ecosystems will exert a warming influence on future climate.
    Beschreibung: We would like to acknowledge the following funding in support of this project: Swedish Research Council (Vetenskapsrådet, VR) grants (NT 2007-4547 and NT 2013-5562 to P. Crill), U.S. Department of Energy grants (DE-SC0004632 and DE-SC0010580 to V. Rich and S. Saleska), and U.S. National Science Foundation MacroSystems Biology grant (NSF EF #1241037, PI Varner). This work was supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research under the Genomic Science program. We also acknowledge funding from the National Science Foundation for the EMERGE Biology Integration Institute, NSF Award #2022070.
    Beschreibung: 2022-07-03
    Schlagwort(e): Peat ; Carbon cycling ; Permafrost ; Carbon-14 ; Lead-210 ; Climate change
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  • 18
    Publikationsdatum: 2022-10-26
    Beschreibung: Author Posting. © American Geophysical Union, 2022. 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: Oceans 127(1), (2022): e2021JC017424, https://doi.org/10.1029/2021JC017424.
    Beschreibung: By compiling boreal summer (June to October) CO2 measurements from 1989 to 2019 on the Bering and eastern Chukchi Sea shelves, we find that the study areas act as a CO2 sink except when impacted by river runoff and wind-driven upwelling. The CO2 system in this area is seasonally dominated by the biological pump especially in the northern Bering Sea and near Hanna Shoal, while wind-driven upwelling of CO2-rich bottom water can cause episodic outgassing. Seasonal surface ΔfCO2 (oceanic fCO2 – air fCO2) is dominantly driven by temperature only during periods of weak CO2 outgassing in shallow nearshore areas. However, after comparing the mean summer ΔfCO2 during the periods of 1989–2013 and 2014–2019, we suggest that temperature does drive long-term, multi-decadal patterns in ΔfCO2. In the northern Chukchi Sea, rapid warming concurrent with reduced seasonal sea-ice persistence caused the regional summer CO2 sink to decrease. By contrast, increasing primary productivity caused the regional summer CO2 sink on the Bering Sea shelf to increase over time. While additional time series are needed to confirm the seasonal and annual trajectory of CO2 changes and ocean acidification in these dynamic and spatially complex ecosystems, this study provides a meaningful mechanistic analysis of recent changes in inorganic carbonate chemistry. As high-resolution time series of inorganic carbonate parameters lengthen and short-term variations are better constrained in the coming decades, we will have stronger confidence in assessing the mechanisms contributing to long-term changes in the source/sink status of regional sub-Arctic seas.
    Beschreibung: We gratefully acknowledge the support of the funding agencies that supported this analysis, including the New Sustained Observations for Arctic Research project and the DBO-NCIS project (NA14OAR4320158, NA19OAR4320074) from the NOAA Arctic Research Program.
    Beschreibung: 2022-06-17
    Schlagwort(e): Pacific Arctic region ; Sea-air CO2 flux ; Ocean acidification ; Climate change ; Sea-ice loss ; Surface ocean CO2 Atlas
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  • 19
    Publikationsdatum: 2022-10-27
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rastetter, E. B., Griffin, K. L., Rowe, R. J., Gough, L., McLaren, J. R., & Boelman, N. T. Model responses to CO(2) and warming are underestimated without explicit representation of Arctic small-mammal grazing. Ecological Applications, (2021): e02478, https://doi.org/10.1002/eap.2478.
    Beschreibung: We use a simple model of coupled carbon and nitrogen cycles in terrestrial ecosystems to examine how “explicitly representing grazers” vs. “having grazer effects implicitly aggregated in with other biogeochemical processes in the model” alters predicted responses to elevated carbon dioxide and warming. The aggregated approach can affect model predictions because grazer-mediated processes can respond differently to changes in climate compared with the processes with which they are typically aggregated. We use small-mammal grazers in a tundra as an example and find that the typical three-to-four-year cycling frequency is too fast for the effects of cycle peaks and troughs to be fully manifested in the ecosystem biogeochemistry. We conclude that implicitly aggregating the effects of small-mammal grazers with other processes results in an underestimation of ecosystem response to climate change, relative to estimations in which the grazer effects are explicitly represented. The magnitude of this underestimation increases with grazer density. We therefore recommend that grazing effects be incorporated explicitly when applying models of ecosystem response to global change.
    Beschreibung: This work was supported in part by the National Science Foundation under NSF grants 1651722, 1637459, 1603560, 1556772, 1841608 to E.B.R.; 1603777 to N.T.B. and K.L.G.; 1603654 to R.J.R.; 1603760 to L.G.; and 1603677 to J.R.M.
    Schlagwort(e): Arctic tundra ; Biogeochemistry ; Carbon cycling ; Carbon-nitrogen ecosystem model ; Climate change ; Nitrogen cycling ; Population cycles ; Small-mammal herbivores
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  • 20
    Publikationsdatum: 2022-10-27
    Beschreibung: Author Posting. © American Geophysical Union, 2021. 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 126(1), (2021): e2019JG005621, https://doi.org/10.1029/2019JG005621.
    Beschreibung: Ongoing ocean warming can release methane (CH4) currently stored in ocean sediments as free gas and gas hydrates. Once dissolved in ocean waters, this CH4 can be oxidized to carbon dioxide (CO2). While it has been hypothesized that the CO2 produced from aerobic CH4 oxidation could enhance ocean acidification, a previous study conducted in Hudson Canyon shows that CH4 oxidation has a small short‐term influence on ocean pH and dissolved inorganic radiocarbon. Here we expand upon that investigation to assess the impact of widespread CH4 seepage on CO2 chemistry and possible accumulation of this carbon injection along 234 km of the U.S. Mid‐Atlantic Bight. Consistent with the estimates from Hudson Canyon, we demonstrate that a small fraction of ancient CH4‐derived carbon is being assimilated into the dissolved inorganic radiocarbon (mean fraction of 0.5 ± 0.4%). The areas with the highest fractions of ancient carbon coincide with elevated CH4 concentration and active gas seepage. This suggests that aerobic CH4 oxidation has a greater influence on the dissolved inorganic pool in areas where CH4 concentrations are locally elevated, instead of displaying a cumulative effect downcurrent from widespread groupings of CH4 seeps. A first‐order approximation of the input rate of ancient‐derived dissolved inorganic carbon (DIC) into the waters overlying the northern U.S. Mid‐Atlantic Bight further suggests that oxidation of ancient CH4‐derived carbon is not negligible on the global scale and could contribute to deepwater acidification over longer time scales.
    Beschreibung: This study was sponsored by U.S. Department of Energy (DE‐FE0028980, awarded to J. D. K; DE‐FE0026195 interagency agreement with C. D. R.). We thank the crew of the R/V Hugh R. Sharp for their support, G. Hatcher, J. Borden, and M. Martini of the USGS for assistance with the LADCP, and Zach Bunnell, Lillian Henderson, and Allison Laubach for additional support at sea.
    Beschreibung: 2021-06-23
    Schlagwort(e): Radiocarbon ; Methane ; DIC ; Ocean acidification ; Climate change ; U.S Mid-Atlantic Bight
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  • 21
    Publikationsdatum: 2022-10-27
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rastetter, E. B., Ohman, M. D., Elliott, K. J., Rehage, J. S., Rivera-Monroy, V. H., Boucek, R. E., Castaneda-Moya, E., Danielson, T. M., Gough, L., Groffman, P. M., Jackson, C. R., Miniat, C. F., & Shaver, G. R. Time lags: insights from the U.S. Long Term Ecological Research Network. Ecosphere, 12(5), (2021): e03431, https://doi.org/10.1002/ecs2.3431.
    Beschreibung: Ecosystems across the United States are changing in complex ways that are difficult to predict. Coordinated long-term research and analysis are required to assess how these changes will affect a diverse array of ecosystem services. This paper is part of a series that is a product of a synthesis effort of the U.S. National Science Foundation’s Long Term Ecological Research (LTER) network. This effort revealed that each LTER site had at least one compelling scientific case study about “what their site would look like” in 50 or 100 yr. As the site results were prepared, themes emerged, and the case studies were grouped into separate papers along five themes: state change, connectivity, resilience, time lags, and cascading effects and compiled into this special issue. This paper addresses the time lags theme with five examples from diverse biomes including tundra (Arctic), coastal upwelling (California Current Ecosystem), montane forests (Coweeta), and Everglades freshwater and coastal wetlands (Florida Coastal Everglades) LTER sites. Its objective is to demonstrate the importance of different types of time lags, in different kinds of ecosystems, as drivers of ecosystem structure and function and how these can effectively be addressed with long-term studies. The concept that slow, interactive, compounded changes can have dramatic effects on ecosystem structure, function, services, and future scenarios is apparent in many systems, but they are difficult to quantify and predict. The case studies presented here illustrate the expanding scope of thinking about time lags within the LTER network and beyond. Specifically, they examine what variables are best indicators of lagged changes in arctic tundra, how progressive ocean warming can have profound effects on zooplankton and phytoplankton in waters off the California coast, how a series of species changes over many decades can affect Eastern deciduous forests, and how infrequent, extreme cold spells and storms can have enduring effects on fish populations and wetland vegetation along the Southeast coast and the Gulf of Mexico. The case studies highlight the need for a diverse set of LTER (and other research networks) sites to sort out the multiple components of time lag effects in ecosystems.
    Beschreibung: This research was supported by the National Science Foundation Long Term Ecological Research program grants to the Arctic (Grants DEB-1637459 and 1026843), California Current (Grants OCE-1637632 and 1026607), Coweeta (Grants DEB-1637522, 1440485, 0823293, 9632854, and 0218001), and Florida Coastal Everglades (Grants DEB-9910514 and 1237517 and DBI-0620409) sites. We also acknowledge the sustained efforts of the CalCOFI program, present and previous staff of the SIO Pelagic Invertebrate Collection, and the late Ed Brinton for his pioneering insights in euphausiid ecology. The Coweeta research and synthesis were also supported by the USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory. Partial funding to VHRM was provided by the U.S. Department of the Interior South-Central Climate Science Center through Cooperative Agreement # G12AC00002.
    Schlagwort(e): Climate change ; Climate change detection ; Climate signal filtering ; Ecosystem response ; Special Feature: Forecasting Earth's Ecosystems with Long-Term Ecological Research
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  • 22
    Publikationsdatum: 2022-10-19
    Beschreibung: Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography and Paleoclimatology 36(7), (2021): e2020PA004088, https://doi.org/10.1029/2020PA004088.
    Beschreibung: We reconstruct deep water-mass salinities and spatial distributions in the western North Atlantic during the Last Glacial Maximum (LGM, 19–26 ka), a period when atmospheric CO2 was significantly lower than it is today. A reversal in the LGM Atlantic meridional bottom water salinity gradient has been hypothesized for several LGM water-mass reconstructions. Such a reversal has the potential to influence climate, ocean circulation, and atmospheric CO2 by increasing the thermal energy and carbon storage capacity of the deep ocean. To test this hypothesis, we reconstructed LGM bottom water salinity based on sedimentary porewater chloride profiles in a north-south transect of piston cores collected from the deep western North Atlantic. LGM bottom water salinity in the deep western North Atlantic determined by the density-based method is 3.41–3.99 ± 0.15% higher than modern values at these sites. This increase is consistent with: (a) the 3.6% global average salinity change expected from eustatic sea level rise, (b) a northward expansion of southern sourced deep water, (c) shoaling of northern sourced deep water, and (d) a reversal of the Atlantic's north-south deep water salinity gradient during the LGM.
    Beschreibung: This work was supported by the US National Science Foundation (grant numbers 1433150 and 1537485).
    Beschreibung: 2021-10-24
    Schlagwort(e): Carbon cycle ; Climate change ; Deep water ; Glaciation ; Meridional overturning circulation ; Paleosalinity ; Porewater
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  • 23
    Publikationsdatum: 2022-10-19
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Zhou, P., Ireland, T., Murray, R. W., & Clift, P. D. Marine sedimentary records of chemical weathering evolution in the western Himalaya since 17 Ma. Geosphere, 17(3), (2021): 824–853, https://doi.org/10.1130/GES02211.1.
    Beschreibung: The Indus Fan derives sediment from the western Himalaya and Karakoram. Sediment from International Ocean Discovery Program drill sites in the eastern part of the fan coupled with data from an industrial well near the river mouth allow the weathering history of the region since ca. 16 Ma to be reconstructed. Clay minerals, bulk sediment geochemistry, and magnetic susceptibility were used to constrain degrees of chemical alteration. Diffuse reflectance spectroscopy was used to measure the abundance of moisture-sensitive minerals hematite and goethite. Indus Fan sediment is more weathered than Bengal Fan material, probably reflecting slow transport, despite the drier climate, which slows chemical weathering rates. Some chemical weathering proxies, such as K/Si or kaolinite/(illite + chlorite), show no temporal evolution, but illite crystallinity and the chemical index of alteration do have statistically measurable decreases over long time periods. Using these proxies, we suggest that sediment alteration was moderate and then increased from 13 to 11 Ma, remained high until 9 Ma, and then reduced from that time until 6 Ma in the context of reduced physical erosion during a time of increasing aridity as tracked by hematite/goethite values. The poorly defined reducing trend in weathering intensity is not clearly linked to global cooling and at least partly reflects regional climate change. Since 6 Ma, weathering has been weak but variable since a final reduction in alteration state after 3.5 Ma that correlates with the onset of Northern Hemispheric glaciation. Reduced or stable chemical weathering at a time of falling sedimentation rates is not consistent with models for Cenozoic global climate change that invoke greater Himalayan weathering fluxes drawing down atmospheric CO2 but are in accord with the idea of greater surface reactivity to weathering.
    Beschreibung: This study was made possible by samples provided by the IODP. The work was partially funded by a grant from The U.S. Science Support Program (USSSP), as well as additional funding from the Charles T. McCord Jr. Endowed Chair in petroleum geology at LSU.
    Schlagwort(e): Alteration ; Arabian Sea ; Arid environment ; Asia ; Bengal Fan ; Chemical composition ; Chemical weathering ; Chlorite ; Chlorite group ; Clay minerals ; Climate change ; Cooling ; Crystallinity ; Emission spectra ; Erosion ; Expedition 355 ; Glaciation ; Goethite ; Grain size ; Hematite ; Himalayas ; ICP mass spectra ; Illite ; Indian Ocean ; Indus Fan ; International Ocean Discovery Program ; IODP Site U1456 ; IODP Site U1457 ; Kaolinite ; Karakoram ; Magnetic properties ; Magnetic susceptibility ; Marine environment ; Mass spectra ; Mineral assemblages ; Moisture ; Oxides ; Paleoclimatology ; Paleoenvironment ; Paleomagnetism ; Provenance ; Reactivity ; Reconstruction ; Sediment transport ; Sedimentary rocks ; Sedimentation ; Sedimentation rates ; Sheet silicates ; Silicates ; Spectra ; Terrestrial environment ; Transport ; Weathering
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  • 24
    Publikationsdatum: 2022-10-20
    Beschreibung: Author Posting. © American Geophysical Union, 2021. 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 57(7), (2021): e2020WR028727, https://doi.org/10.1029/2020WR028727.
    Beschreibung: Numerous wetlands in the prairies of Canada provide important ecosystem services, yet are threatened by climate and land-use changes. Understanding the impacts of climate change on prairie wetlands is critical to effective conservation planning. In this study, we construct a wetland model with surface water balance and ecoregions to project future distribution of wetlands. The climatic conditions downscaled from the Weather Research and Forecasting model were used to drive the Noah-MP land surface model to obtain surface water balance. The climate change perturbation is derived from an ensemble of general circulation models using the pseudo global warming method, under the RCP8.5 emission scenario by the end of 21st century. The results show that climate change impacts on wetland extent are spatiotemporally heterogenous. Future wetter climate in the western Prairies will favor increased wetland abundance in both spring and summer. In the eastern Prairies, particularly in the mixed grassland and mid-boreal upland, wetland areas will increase in spring but experience enhanced declines in summer due to strong evapotranspiration. When these effects of climate change are considered in light of historical drainage, they suggest a need for diverse conservation and restoration strategies. For the mixed grassland in the western Canadian Prairies, wetland restoration will be favorable, while the highly drained eastern Prairies will be challenged by the intensified hydrological cycle. The outcomes of this study will be useful to conservation agencies to ensure that current investments will continue to provide good conservation returns in the future.
    Beschreibung: Z. Zhang was funded by a Mitacs Accelerate Fellowship funded by Ducks Unlimited Canada's Institute for Wetland and Waterfowl Research. Z. Zhang, Z. Li, and Y. Li acknowledge the financial support from the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant, and Global Water Futures Program, Canada First Research Excellence Fund. This project was supported by grants from Wildlife Habitat Canada, Bass Pro Shops Cabela’s Outdoor Fund, and the Alberta NAWMP Partnership.
    Beschreibung: 2021-12-21
    Schlagwort(e): Wetland ; Hydrology ; Climate change ; Prairie Pothole Region ; Waterfowl ; Conservation
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  • 25
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    American Meteorological Society
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 50(12),(2020): 3623-3639, https://doi.org/10.1175/JPO-D-20-0173.1
    Beschreibung: Sea level rise over the last deglaciation is dominated by the mass of freshwater added to the oceans by the melting of the great ice sheets. While the steric effect of changing seawater density is secondary over the last 20 000 years, processes connected to deglacial warming, the redistribution of salt, and the pressure load of meltwater all influence sea level rise by more than a meter. Here we develop a diagnostic for steric effects that is valid when oceanic mass is changing. This diagnostic accounts for seawater compression due to the added overlying pressure of glacial meltwater, which is here defined to be a barosteric effect. Analysis of three-dimensional global seawater reconstructions of the last deglaciation indicates that thermosteric height change (1.0–1.5 m) is counteracted by barosteric (−1.9 m) and halosteric (from −0.4 to 0.0 m) effects. The total deglacial steric effect from −0.7 to −1.1 m has the opposite sign of analyses that assume that thermosteric expansion is dominant. Despite the vertical oceanic structure not being well constrained during the Last Glacial Maximum, net seawater contraction appears robust as it occurs in four reconstructions that were produced using different paleoceanographic datasets. Calculations that do not account for changes in ocean pressure give the misleading impression that steric effects enhanced deglacial sea level rise.
    Beschreibung: GG is supported by NSF OCE-1536380 and OCE-1760878.
    Beschreibung: 2021-06-01
    Schlagwort(e): Abyssal circulation ; Sea level ; Water masses/storage ; Climate change ; Glaciation ; Water budget/balance
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  • 26
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 33(22), (2020): 9883-9903, https://doi.org/10.1175/JCLI-D-20-0004.1.
    Beschreibung: Machine-learning-based methods that identify drought in three-dimensional space–time are applied to climate model simulations and tree-ring-based reconstructions of hydroclimate over the Northern Hemisphere extratropics for the past 1000 years, as well as twenty-first-century projections. Analyzing reconstructed and simulated drought in this context provides a paleoclimate constraint on the spatiotemporal characteristics of simulated droughts. Climate models project that there will be large increases in the persistence and severity of droughts over the coming century, but with little change in their spatial extent. Nevertheless, climate models exhibit biases in the spatiotemporal characteristics of persistent and severe droughts over parts of the Northern Hemisphere. We use the paleoclimate record and results from a linear inverse modeling-based framework to conclude that climate models underestimate the range of potential future hydroclimate states. Complicating this picture, however, are divergent changes in the characteristics of persistent and severe droughts when quantified using different hydroclimate metrics. Collectively our results imply that these divergent responses and the aforementioned biases must be better understood if we are to increase confidence in future hydroclimate projections. Importantly, the novel framework presented herein can be applied to other climate features to robustly describe their spatiotemporal characteristics and provide constraints on future changes to those characteristics.
    Beschreibung: This material is based upon work supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation under Cooperative Agreement 1852977. JAF was also supported by the Regional and Global Model Analysis (RGMA) component of the Earth and Environmental System Modeling Program of the U.S. Department of Energy's Office of Biological & Environmental Research (BER) via National Science Foundation IA 1844590. JS was supported in part by the U.S. National Science Foundation through Grants AGS-1602920 and AGS-1805490, and by the National Oceanic and Atmospheric Administration by Grant NA20OAR4310425. We acknowledge the World Climate Research Programme’s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups (listed in Table 1) for producing and making available their model output. For CMIP, the U.S. Department of Energy’s Program for Climate Model Diagnosis and Intercomparison provides coordinating support and led development of software infrastructure in partnership with the Global Organization for Earth System Science Portal. We thank the editor and two reviewers for comments that greatly improved the quality of this manuscript. This is SOEST Publication No. 11116 and LDEO Publication No. 8450.
    Beschreibung: 2021-04-15
    Schlagwort(e): Drought ; Climate change ; Paleoclimate ; Climate models ; Climate variability ; Other artificial intelligence/machine learning
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Publikationsdatum: 2022-10-26
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Day, J., Goodman, R., Chen, Z., Hunter, R., Giosan, L., & Wang, Y. Deltas in arid environments. Water, 13(12), (2021): 1677, https://doi.org/10.3390/w13121677.
    Beschreibung: Due to increasing water use, diversion and salinization, along with subsidence and sea-level rise, deltas in arid regions are shrinking worldwide. Some of the most ecologically important arid deltas include the Colorado, Indus, Nile, and Tigris-Euphrates. The primary stressors vary globally, but these deltas are threatened by increased salinization, water storage and diversion, eutrophication, and wetland loss. In order to make these deltas sustainable over time, some water flow, including seasonal flooding, needs to be re-established. Positive impacts have been seen in the Colorado River delta after flows to the delta were increased. In addition to increasing freshwater flow, collaboration among stakeholders and active management are necessary. For the Nile River, cooperation among different nations in the Nile drainage basin is important. River flow into the Tigris-Euphrates River delta has been affected by politics and civil strife in the Middle East, but some flow has been re-allocated to the delta. Studies commissioned for the Indus River delta recommended re-establishment of some monthly water flow to maintain the river channel and to fight saltwater intrusion. However, accelerating climate impacts, socio-political conflicts, and growing populations suggest a dire future for arid deltas.
    Beschreibung: This research received no external funding.
    Schlagwort(e): Salinization ; Climate change ; Colorado river ; Tigris-Euphrates river ; Nile river ; Indus river
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 28
    Publikationsdatum: 2022-10-26
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bernhard, J. M., Wit, J. C., Starczak, V. R., Beaudoin, D. J., Phalen, W. G., & McCorkle, D. C. Impacts of multiple stressors on a benthic foraminiferal community: a long-term experiment assessing response to ocean acidification, hypoxia and warming. Frontiers in Marine Science, 8, (2021): 643339, https://doi.org/10.3389/fmars.2021.643339.
    Beschreibung: Ocean chemistry is changing as a result of human activities. Atmospheric carbon dioxide (CO2) concentrations are increasing, causing an increase in oceanic pCO2 that drives a decrease in oceanic pH, a process called ocean acidification (OA). Higher CO2 concentrations are also linked to rising global temperatures that can result in more stratified surface waters, reducing the exchange between surface and deep waters; this stronger stratification, along with nutrient pollution, contributes to an expansion of oxygen-depleted zones (so called hypoxia or deoxygenation). Determining the response of marine organisms to environmental changes is important for assessments of future ecosystem functioning. While many studies have assessed the impact of individual or paired stressors, fewer studies have assessed the combined impact of pCO2, O2, and temperature. A long-term experiment (∼10 months) with different treatments of these three stressors was conducted to determine their sole or combined impact on the abundance and survival of a benthic foraminiferal community collected from a continental-shelf site. Foraminifera are well suited to such study because of their small size, relatively rapid growth, varied mineralogies and physiologies. Inoculation materials were collected from a ∼77-m deep site south of Woods Hole, MA. Very fine sediments (〈53 μm) were used as inoculum, to allow the entire community to respond. Thirty-eight morphologically identified taxa grew during the experiment. Multivariate statistical analysis indicates that hypoxia was the major driving factor distinguishing the yields, while warming was secondary. Species responses were not consistent, with different species being most abundant in different treatments. Some taxa grew in all of the triple-stressor samples. Results from the experiment suggest that foraminiferal species’ responses will vary considerably, with some being negatively impacted by predicted environmental changes, while other taxa will tolerate, and perhaps even benefit, from deoxygenation, warming and OA.
    Beschreibung: This work was supported by the US NSF SEES-OA grant OCE-1219948 to JB and the Investment in Science Program at WHOI. DM also received support from the NSF Independent Research and Development Program.
    Schlagwort(e): Deoxygenation ; Ocean acidification ; Benthic communities ; Benthic foraminifera ; Climate change ; Propagule bank ; Global warming
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 29
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Hahn, L. C., Storelvmo, T., Hofer, S., Parfitt, R., & Ummenhofer, C. C. Importance of Orography for Greenland cloud and melt response to atmospheric blocking. Journal of Climate, 33(10), (2020): 4187-4206, doi:10.1175/JCLI-D-19-0527.1.
    Beschreibung: More frequent high pressure conditions associated with atmospheric blocking episodes over Greenland in recent decades have been suggested to enhance melt through large-scale subsidence and cloud dissipation, which allows more solar radiation to reach the ice sheet surface. Here we investigate mechanisms linking high pressure circulation anomalies to Greenland cloud changes and resulting cloud radiative effects, with a focus on the previously neglected role of topography. Using reanalysis and satellite data in addition to a regional climate model, we show that anticyclonic circulation anomalies over Greenland during recent extreme blocking summers produce cloud changes dependent on orographic lift and descent. The resulting increased cloud cover over northern Greenland promotes surface longwave warming, while reduced cloud cover in southern and marginal Greenland favors surface shortwave warming. Comparison with an idealized model simulation with flattened topography reveals that orographic effects were necessary to produce area-averaged decreasing cloud cover since the mid-1990s and the extreme melt observed in the summer of 2012. This demonstrates a key role for Greenland topography in mediating the cloud and melt response to large-scale circulation variability. These results suggest that future melt will depend on the pattern of circulation anomalies as well as the shape of the Greenland Ice Sheet.
    Beschreibung: This research was supported by the Woods Hole Oceanographic Institution Summer Student Fellow program, by the U.S. National Science Foundation under AGS-1355339 to C.C.U., and by the European Research Council through Grant 758005.
    Schlagwort(e): Ice sheets ; Blocking ; Cloud cover ; Topographic effects ; Climate change ; Climate variability
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 30
    Publikationsdatum: 2022-10-27
    Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scalpone, C. R., Jarvis, J. C., Vasslides, J. M., Testa, J. M., & Ganju, N. K. Simulated estuary-wide response of seagrass (Zostera marina) to future scenarios of temperature and sea level. Frontiers in Marine Science, 7, (2020): 539946, doi:10.3389/fmars.2020.539946.
    Beschreibung: Seagrass communities are a vital component of estuarine ecosystems, but are threatened by projected sea level rise (SLR) and temperature increases with climate change. To understand these potential effects, we developed a spatially explicit model that represents seagrass (Zostera marina) habitat and estuary-wide productivity for Barnegat Bay-Little Egg Harbor (BB-LEH) in New Jersey, United States. Our modeling approach included an offline coupling of a numerical seagrass biomass model with the spatially variable environmental conditions from a hydrodynamic model to calculate above and belowground biomass at each grid cell of the hydrodynamic model domain. Once calibrated to represent present day seagrass habitat and estuary-wide annual productivity, we applied combinations of increasing air temperature and sea level following regionally specific climate change projections, enabling analysis of the individual and combined impacts of these variables on seagrass biomass and spatial coverage. Under the SLR scenarios, the current model domain boundaries were maintained, as the land surrounding BB-LEH is unlikely to shift significantly in the future. SLR caused habitat extent to decrease dramatically, pushing seagrass beds toward the coastline with increasing depth, with a 100% loss of habitat by the maximum SLR scenario. The dramatic loss of seagrass habitat under SLR was in part due to the assumption that surrounding land would not be inundated, as the model did not allow for habitat expansion outside the current boundaries of the bay. Temperature increases slightly elevated the rate of summer die-off and decreased habitat area only under the highest temperature increase scenarios. In combined scenarios, the effects of SLR far outweighed the effects of temperature increase. Sensitivity analysis of the model revealed the greatest sensitivity to changes in parameters affecting light limitation and seagrass mortality, but no sensitivity to changes in nutrient limitation constants. The high vulnerability of seagrass in the bay to SLR exceeded that demonstrated for other systems, highlighting the importance of site- and region-specific assessments of estuaries under climate change.
    Beschreibung: This research was supported by the National Science Foundation Research Experience for Undergraduates Program (OCE-1659463), the Woods Hole Oceanographic Institution Summer Student Fellowship Program, the Barnegat Bay Partnership (through a US EPA Clean Water Act grant to Ocean County College; CE98212313), and the USGS Coastal and Marine Hazards/Resources Program. Although this project has been funded in part by the United States Environmental Protection Agency pursuant to a grant agreement with Ocean County College, it has not gone through the Agency’s publications review process and may not necessarily reflect the views of the Agency; therefore, no official endorsement should be assumed. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
    Schlagwort(e): Seagrass (Zostera) ; Climate change ; Spatial model ; Sea level rise ; Temperature ; North American Atlantic Coast ; Regional ; Eelgrass (Zostera marina)
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 31
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    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Ehux growth rates under thermal variation
    Beschreibung: This dataset includes the growth rates under low and high temperatures for E. huxleyi in constant and fluctuating thermal environments. Global warming will be combined with predicted increases in thermal variability in the future surface ocean, but how temperature dynamics will affect phytoplankton biology and biogeochemistry is largely unknown. Here, we examine the responses of the globally important marine coccolithophore Emiliania huxleyi to thermal variations at two frequencies (1 d and 2 d) at low (18.5 °C) and high (25.5 °C) mean temperatures. Elevated temperature and thermal variation decreased growth, calcification and physiological rates, both individually and interactively. The 1 d thermal variation frequencies were less inhibitory than 2 d variations under high temperatures, indicating that high-frequency thermal fluctuations may reduce heat-induced mortality and mitigate some impacts of extreme high-temperature events. Cellular elemental composition and calcification was significantly affected by both thermal variation treatments relative to each other and to the constant temperature controls. The negative effects of thermal variation on E. huxleyi growth rate and physiology are especially pronounced at high temperatures. These responses of the key marine calcifier E. huxleyi to warmer, more variable temperature regimes have potentially large implications for ocean productivity and marine biogeochemical cycles under a future changing climate. 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/782888
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1538525
    Schlagwort(e): Thermal Performance Curves ; Growth Rates ; Emiliania huxleyi ; Climate change ; Calcification ; Elemental quotas
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    facet.materialart.
    Unbekannt
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Ehux physiology under thermal variation
    Beschreibung: Intracellular elemental quotas under low and high temperatures for E. huxleyi in constant and fluctuating thermal environments. This dataset includes the growth rates under low and high temperatures for E. huxleyi in constant and fluctuating thermal environments. Global warming will be combined with predicted increases in thermal variability in the future surface ocean, but how temperature dynamics will affect phytoplankton biology and biogeochemistry is largely unknown. Here, we examine the responses of the globally important marine coccolithophore Emiliania huxleyi to thermal variations at two frequencies (1 d and 2 d) at low (18.5 °C) and high (25.5 °C) mean temperatures. Elevated temperature and thermal variation decreased growth, calcification and physiological rates, both individually and interactively. The 1 d thermal variation frequencies were less inhibitory than 2 d variations under high temperatures, indicating that high-frequency thermal fluctuations may reduce heat-induced mortality and mitigate some impacts of extreme high-temperature events. Cellular elemental composition and calcification was significantly affected by both thermal variation treatments relative to each other and to the constant temperature controls. The negative effects of thermal variation on E. huxleyi growth rate and physiology are especially pronounced at high temperatures. These responses of the key marine calcifier E. huxleyi to warmer, more variable temperature regimes have potentially large implications for ocean productivity and marine biogeochemical cycles under a future changing climate. 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/782901
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1538525
    Schlagwort(e): Thermal Performance Curves ; Growth Rates ; Emiliania huxleyi ; Climate change ; Calcification ; Elemental quotas
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    facet.materialart.
    Unbekannt
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Thalassiosira pseudonana CCMP1335 in nitrate-limited and nutrient-replete cultures
    Beschreibung: The marine diatom Thalassiosira pseudonana clone CCMP 1335 was grown in a continuous culture system on a 14:10 light-dark cycle under either nitrate-limited or nutrient-replete conditions, a photoperiod irradiance of either 50 or 300 micro-mol photons per square meter per second, partial pressures of either 400 or 1000 ppm CO2, and temperatures ranging from 5 to 32 degrees Celsius. Growth rates, photosynthetic rates, respiration rates, C:N ratios, C:Chlorophyll-a ratios, productivity indices, Fv/Fm ratios, and the initial slope and light-saturated asymptote of short-term photosynthesis-irradiance curves are reported. 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/779368
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1536581
    Schlagwort(e): Climate change ; Phytoplankton ; Light ; Temperature ; CO2 partial pressure ; Acclimation
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    facet.materialart.
    Unbekannt
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Ehux growth rates for thermal response curve
    Beschreibung: This dataset presents growth rates for Emiliania huxleyi thermal response curve across 12 temperatures from 8.5-28.6C.Global warming will be combined with predicted increases in thermal variability in the future surface ocean, but how temperature dynamics will affect phytoplankton biology and biogeochemistry is largely unknown. Here, we examine the responses of the globally important marine coccolithophore Emiliania huxleyi to thermal variations at two frequencies (1 d and 2 d) at low (18.5 °C) and high (25.5 °C) mean temperatures. Elevated temperature and thermal variation decreased growth, calcification and physiological rates, both individually and interactively. The 1 d thermal variation frequencies were less inhibitory than 2 d variations under high temperatures, indicating that high-frequency thermal fluctuations may reduce heat-induced mortality and mitigate some impacts of extreme high-temperature events. Cellular elemental composition and calcification was significantly affected by both thermal variation treatments relative to each other and to the constant temperature controls. The negative effects of thermal variation on E. huxleyi growth rate and physiology are especially pronounced at high temperatures. These responses of the key marine calcifier E. huxleyi to warmer, more variable temperature regimes have potentially large implications for ocean productivity and marine biogeochemical cycles under a future changing climate. 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/782911
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1538525
    Schlagwort(e): Thermal Performance Curves ; Growth Rates ; Emiliania huxleyi ; Climate change ; Calcification ; Elemental quotas
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    facet.materialart.
    Unbekannt
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Ehux elemental composition across thermal range
    Beschreibung: This dataset includes elemental stoichiometry for Emiliania huxleyi across a range of 12 temperatures from 8.5-28.6C. Global warming will be combined with predicted increases in thermal variability in the future surface ocean, but how temperature dynamics will affect phytoplankton biology and biogeochemistry is largely unknown. Here, we examine the responses of the globally important marine coccolithophore Emiliania huxleyi to thermal variations at two frequencies (1 d and 2 d) at low (18.5 °C) and high (25.5 °C) mean temperatures. Elevated temperature and thermal variation decreased growth, calcification and physiological rates, both individually and interactively. The 1 d thermal variation frequencies were less inhibitory than 2 d variations under high temperatures, indicating that high-frequency thermal fluctuations may reduce heat-induced mortality and mitigate some impacts of extreme high-temperature events. Cellular elemental composition and calcification was significantly affected by both thermal variation treatments relative to each other and to the constant temperature controls. The negative effects of thermal variation on E. huxleyi growth rate and physiology are especially pronounced at high temperatures. These responses of the key marine calcifier E. huxleyi to warmer, more variable temperature regimes have potentially large implications for ocean productivity and marine biogeochemical cycles under a future changing climate. 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/782921
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1538525
    Schlagwort(e): Thermal Performance Curves ; Growth Rates ; Emiliania huxleyi ; Climate change ; Calcification ; Elemental quotas
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    facet.materialart.
    Unbekannt
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Gill Net Catch Data
    Beschreibung: Vertebrate caught with gill net in Sabine Lake, Galveston Bay, Matagorda Bay, San Antonio Bay, Aransas Bay, Corpus Christi Bay, Upper Laguna Madre, and Lower Laguna Madre from 1986 to 2018 (except in Sabine Lake sampling begun in 1986). 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/828794
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1656923
    Schlagwort(e): Marine biodiversity ; Climate change ; Coastal ecosystems ; Fish diversity
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    facet.materialart.
    Unbekannt
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publikationsdatum: 2022-10-31
    Beschreibung: Dataset: Synechococcus elongatus CCMP1629 in nitrate-limited and nutrient-replete cultures
    Beschreibung: The marine cyanobacterium Synechococcus elongatus clone CCMP1629 was grown in a continuous culture system on a 14:10 light-dark cycle under either nitrate-limited or nutrient-replete conditions, a photoperiod irradiance of either 50 or 300 micro-mol photons per square meter per second, partial pressures of either 400 or 1000 ppm CO2, and temperatures ranging from 20 to 45 degrees Celsius. Growth rates, photosynthetic rates, respiration rates, C:N ratios, C:Chlorophyll-a ratios, productivity indices, Fv/Fm ratios, and the initial slope and light-saturated asymptote of short-term photosynthesis-irradiance curves are reported. 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/811093
    Beschreibung: NSF Division of Ocean Sciences (NSF OCE) OCE-1536581
    Schlagwort(e): Climate change ; Phytoplankton ; Light ; Temperature ; CO2 partial pressure ; Acclimation
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
    Standort Signatur Erwartet Verfügbarkeit
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  • 38
    Publikationsdatum: 2022-10-26
    Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wagner, S., Schubotz, F., Kaiser, K., Hallmann, C., Waska, H., Rossel, P. E., Hansmann, R., Elvert, M., Middelburg, J. J., Engel, A., Blattmann, T. M., Catala, T. S., Lennartz, S. T., Gomez-Saez, G., V., Pantoja-Gutierrez, S., Bao, R., & Galy, V. Soothsaying DOM: A current perspective on the future of oceanic dissolved organic carbon. Frontiers in Marine Science, 7, (2020): 341, doi:10.3389/fmars.2020.00341.
    Beschreibung: The vast majority of freshly produced oceanic dissolved organic carbon (DOC) is derived from marine phytoplankton, then rapidly recycled by heterotrophic microbes. A small fraction of this DOC survives long enough to be routed to the interior ocean, which houses the largest and oldest DOC reservoir. DOC reactivity depends upon its intrinsic chemical composition and extrinsic environmental conditions. Therefore, recalcitrance is an emergent property of DOC that is analytically difficult to constrain. New isotopic techniques that track the flow of carbon through individual organic molecules show promise in unveiling specific biosynthetic or degradation pathways that control the metabolic turnover of DOC and its accumulation in the deep ocean. However, a multivariate approach is required to constrain current carbon fluxes so that we may better predict how the cycling of oceanic DOC will be altered with continued climate change. Ocean warming, acidification, and oxygen depletion may upset the balance between the primary production and heterotrophic reworking of DOC, thus modifying the amount and/or composition of recalcitrant DOC. Climate change and anthropogenic activities may enhance mobilization of terrestrial DOC and/or stimulate DOC production in coastal waters, but it is unclear how this would affect the flux of DOC to the open ocean. Here, we assess current knowledge on the oceanic DOC cycle and identify research gaps that must be addressed to successfully implement its use in global scale carbon models.
    Beschreibung: This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) project number 422798570. The Hanse-Wissenschaftskolleg and the Geochemical Society provided funding for the conference. Additional support was provided by the National Science Foundation OCE #1756812 to SW. TB acknowledges funding from ETH Zürich and JAMSTEC. JM was supported by the Netherlands Earth System Science Centre. SP-G was funded by COPAS Sur-Austral (CONICYT PIA APOYO CCTE AFB170006). GG-S acknowledges funding from DFG, DI 842/6-1.
    Schlagwort(e): Dissolved organic carbon ; Global carbon cycle ; Recalcitrance ; Isotopic probing ; Climate change
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 39
    Publikationsdatum: 2022-10-26
    Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Benthuysen, J. A., Oliver, E. C. J., Chen, K., & Wernberg, T. Editorial: advances in understanding marine heatwaves and their impacts. Frontiers in Marine Science, 7, (2020): 147, doi:10.3389/fmars.2020.00147.
    Beschreibung: Editorial on the Research Topic Advances in Understanding Marine Heatwaves and Their Impacts In recent years, prolonged, extremely warm water events, known as marine heatwaves, have featured prominently around the globe with their disruptive consequences for marine ecosystems. Over the past decade, marine heatwaves have occurred from the open ocean to marginal seas and coastal regions, including the unprecedented 2011 Western Australia marine heatwave (Ningaloo Niño) in the eastern Indian Ocean (e.g., Pearce et al., 2011), the 2012 northwest Atlantic marine heatwave (Chen et al., 2014), the 2012 and 2015 Mediterranean Sea marine heatwaves (Darmaraki et al., 2019), the 2013/14 western South Atlantic (Rodrigues et al., 2019) and 2017 southwestern Atlantic marine heatwave (Manta et al., 2018), the persistent 2014–2016 “Blob” in the North Pacific (Bond et al., 2015; Di Lorenzo and Mantua, 2016), the 2015/16 marine heatwave spanning the southeastern tropical Indian Ocean to the Coral Sea (Benthuysen et al., 2018), and the Tasman Sea marine heatwaves in 2015/16 (Oliver et al., 2017) and 2017/18 (Salinger et al., 2019). These events have set new records for marine heatwave intensity, the temperature anomaly exceeding a climatology, and duration, the sustained period of extreme temperatures. We have witnessed the profound consequences of these thermal disturbances from acute changes to marine life to enduring impacts on species, populations, and communities (Smale et al., 2019). These marine heatwaves have spurred a diversity of research spanning the methodology of identifying and quantifying the events (e.g., Hobday et al., 2016) and their historical trends (Oliver et al., 2018), understanding their physical mechanisms and relationships with climate modes (e.g., Holbrook et al., 2019), climate projections (Frölicher et al., 2018), and understanding the biological impacts for organisms and ecosystem function and services (e.g., Smale et al., 2019). By using sea surface temperature percentiles, temperature anomalies can be quantified based on their local variability and account for the broad range of temperature regimes in different marine environments. For temperatures exceeding a 90th-percentile threshold beyond a period of 5-days, marine heatwaves can be classified into categories based on their intensity (Hobday et al., 2018). While these recent advances have provided the framework for understanding key aspects of marine heatwaves, a challenge lies ahead for effective integration of physical and biological knowledge for prediction of marine heatwaves and their ecological impacts. This Research Topic is motivated by the need to understand the mechanisms for how marine heatwaves develop and the biological responses to thermal stress events. This Research Topic is a collection of 18 research articles and three review articles aimed at advancing our knowledge of marine heatwaves within four themes. These themes include methods for detecting marine heatwaves, understanding their physical mechanisms, seasonal forecasting and climate projections, and ecological impacts.
    Beschreibung: We thank the contributing authors, reviewers, and the editorial staff at Frontiers in Marine Science for their support in producing this issue. We thank the Marine Heatwaves Working Group (http://www.marineheatwaves.org/) for inspiration and discussions. This special issue stemmed from the session on Advances in Understanding Marine Heat Waves and Their Impacts at the 2018 Ocean Sciences meeting (Portland, USA).
    Schlagwort(e): Marine heatwaves ; Extreme events ; Ocean and atmosphere interactions ; Marine ecosystems ; Marine resources ; Climate change ; Climate variability ; Climate prediction
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  • 40
    Publikationsdatum: 2022-05-26
    Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Trathan, P. N., Wienecke, B., Barbraud, C., Jenouvrier, S., Kooyman, G., Le Bohec, C., Ainley, D. G., Ancel, A., Zitterbart, D. P., Chown, S. L., LaRue, M., Cristofari, R., Younger, J., Clucas, G., Bost, C., Brown, J. A., Gillett, H. J., & Fretwell, P. T. The emperor penguin - vulnerable to projected rates of warming and sea ice loss. Biological Conservation, 241, (2020): 108216, doi:10.1016/j.biocon.2019.108216.
    Beschreibung: We argue the need to improve climate change forecasting for ecology, and importantly, how to relate long-term projections to conservation. As an example, we discuss the need for effective management of one species, the emperor penguin, Aptenodytes forsteri. This species is unique amongst birds in that its breeding habit is critically dependent upon seasonal fast ice. Here, we review its vulnerability to ongoing and projected climate change, given that sea ice is susceptible to changes in winds and temperatures. We consider published projections of future emperor penguin population status in response to changing environments. Furthermore, we evaluate the current IUCN Red List status for the species, and recommend that its status be changed to Vulnerable, based on different modelling projections of population decrease of ≥50% over the current century, and the specific traits of the species. We conclude that current conservation measures are inadequate to protect the species under future projected scenarios. Only a reduction in anthropogenic greenhouse gas emissions will reduce threats to the emperor penguin from altered wind regimes, rising temperatures and melting sea ice; until such time, other conservation actions are necessary, including increased spatial protection at breeding sites and foraging locations. The designation of large-scale marine spatial protection across its range would benefit the species, particularly in areas that have a high probability of becoming future climate change refugia. We also recommend that the emperor penguin is listed by the Antarctic Treaty as an Antarctic Specially Protected Species, with development of a species Action Plan.
    Beschreibung: We thank Thomas J. Bracegirdle, Tony Phillips and Kevin Hughes for helpful comments on earlier drafts of this manuscript. PNT acknowledges the support of WWF-UK under GB095701 and SJ the support of NSF OPP1744794 and 1643901.
    Schlagwort(e): Antarctic ; Climate change ; Aptenodytes forsteri ; IUCN Red List threat status ; Protection ; Conservation
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  • 41
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    American Meteorological Society
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 50(1), (2020): 255-268, doi:10.1175/JPO-D-19-0166.1.
    Beschreibung: Regional connectivity is important to the global climate salinity response, particularly because salinity anomalies do not have a damping feedback with atmospheric freshwater fluxes and may therefore be advected over long distances by ocean circulation, resulting in nonlocal influences. Climate model intercomparison experiments such as CMIP5 exhibit large uncertainty in some aspects of the salinity response, hypothesized here to be a result of ocean dynamics. We use two types of Lagrangian particle tracking experiments to investigate pathways of exchange for salinity anomalies. The first uses forward trajectories to estimate average transport time scales between water cycle regimes. The second uses reverse trajectories and a freshwater accumulation method to quantitatively identify remote influences in the salinity response. Additionally, we compare velocity fields with both resolved and parameterized eddies to understand the impact of eddy stirring on intergyre exchange. These experiments show that surface anomalies are readily exchanged within the ocean gyres by the mean circulation, but intergyre exchange is slower and largely eddy driven. These dynamics are used to analyze the North Atlantic salinity response to climate warming and water cycle intensification, where the system is broadly forced with fresh surface anomalies in the subpolar gyre and salty surface anomalies in the subtropical gyres. Under these competing forcings, strong intergyre eddy fluxes carry anomalously salty subtropical water into the subpolar gyre which balances out much of the local freshwater input.
    Beschreibung: We acknowledge the World Climate Research Programme’s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups (listed in Table 1 of this paper) for producing and making available their model output. We also thank the creators of the SODA and ECCO reanalysis products. This work was supported by NASA Headquarters under the NASA Earth and Space Science Fellowship Program Award 80NSSC17K0372, and by National Science Foundation Award OCE-1433132. The SODA outputs used here can be accessed at http://www.atmos.umd.edu/~ocean/, and the ECCO outputs at https://ecco.jpl.nasa.gov/. Data from the CMIP5 ensemble is available at https://esgf-node.llnl.gov/projects/esgf-llnl/. The particle tracking code used for these experiments can be found at https://github.com/slevang/particle-tracking.
    Beschreibung: 2020-07-20
    Schlagwort(e): North Atlantic Ocean ; Eddies ; Hydrologic cycle ; Lagrangian circulation/transport ; Transport ; Climate change
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  • 42
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 33(9), (2020): 3863-3882, doi:10.1175/JCLI-D-19-0687.1.
    Beschreibung: The direct response of the cold-season atmospheric circulation to the Arctic sea ice loss is estimated from observed sea ice concentration (SIC) and an atmospheric reanalysis, assuming that the atmospheric response to the long-term sea ice loss is the same as that to interannual pan-Arctic SIC fluctuations with identical spatial patterns. No large-scale relationship with previous interannual SIC fluctuations is found in October and November, but a negative North Atlantic Oscillation (NAO)/Arctic Oscillation follows the pan-Arctic SIC fluctuations from December to March. The signal is field significant in the stratosphere in December, and in the troposphere and tropopause thereafter. However, multiple regressions indicate that the stratospheric December signal is largely due to concomitant Siberian snow-cover anomalies. On the other hand, the tropospheric January–March NAO signals can be unambiguously attributed to SIC variability, with an Iceland high approaching 45 m at 500 hPa, a 2°C surface air warming in northeastern Canada, and a modulation of blocking activity in the North Atlantic sector. In March, a 1°C northern Europe cooling is also attributed to SIC. An SIC impact on the warm Arctic–cold Eurasia pattern is only found in February in relation to January SIC. Extrapolating the most robust results suggests that, in the absence of other forcings, the SIC loss between 1979 and 2016 would have induced a 2°–3°C decade−1 winter warming in northeastern North America and a 40–60 m decade−1 increase in the height of the Iceland high, if linearity and perpetual winter conditions could be assumed.
    Beschreibung: This research was supported by the Blue-Action project (European Union’s Horizon 2020 research and innovation program, Grant 727852) and by the National Science Foundation (OPP 1736738).
    Beschreibung: 2020-10-06
    Schlagwort(e): Atmosphere-ocean interaction ; Climate change ; Climate variability ; Ice loss/growth
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  • 43
    Publikationsdatum: 2022-10-26
    Beschreibung: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Proshutinsky, A., Krishfield, R., Toole, J. M., Timmermans, M-L., Williams, W. J., Zimmermann, S., Yamamoto-Kawai, M., Armitage, T. W. K., Dukhovskoy, D., Golubeva, E., Manucharyan, G. E., Platov, G., Watanabe, E., Kikuchi, T., Nishino, S., Itoh, M., Kang, S-H., Cho, K-H., Tateyama, K., & Zhao, J. Analysis of the Beaufort Gyre freshwater content in 2003-2018. Journal of Geophysical Research-Oceans, 124(12), (2019): 9658-9689, doi:10.1029/2019JC015281.
    Beschreibung: Hydrographic data collected from research cruises, bottom‐anchored moorings, drifting Ice‐Tethered Profilers, and satellite altimetry in the Beaufort Gyre region of the Arctic Ocean document an increase of more than 6,400 km3 of liquid freshwater content from 2003 to 2018: a 40% growth relative to the climatology of the 1970s. This fresh water accumulation is shown to result from persistent anticyclonic atmospheric wind forcing (1997–2018) accompanied by sea ice melt, a wind‐forced redirection of Mackenzie River discharge from predominantly eastward to westward flow, and a contribution of low salinity waters of Pacific Ocean origin via Bering Strait. Despite significant uncertainties in the different observations, this study has demonstrated the synergistic value of having multiple diverse datasets to obtain a more comprehensive understanding of Beaufort Gyre freshwater content variability. For example, Beaufort Gyre Observational System (BGOS) surveys clearly show the interannual increase in freshwater content, but without satellite or Ice‐Tethered Profiler measurements, it is not possible to resolve the seasonal cycle of freshwater content, which in fact is larger than the year‐to‐year variability, or the more subtle interannual variations.
    Beschreibung: National Science Foundation. Grant Numbers: PLR‐1302884,OPP‐1719280, and OPP‐1845877, PLR‐1303644 and OPP‐1756100, OPP‐1756100, PLR‐1303644, OPP‐1845877, OPP‐1719280, PLR‐1302884 Key Program of National Natural Science Foundation of China. Grant Number: 41330960 Global Change Research Program of China. Grant Number: 2015CB953900 Ministry of Education, Korea Japan Aerospace Exploration Agency (JAXA) /Earth Observation Research Center (EORC) Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) Stanback Postdoctoral Fellowship Russian Foundation for Basic Research. Grant Number: 17‐05‐00382 Presidium of Russian Academy of Sciences HYCOM NOPP. Grant Number: N00014‐15‐1‐2594 DOE. Grant Number: DE‐SC0014378 National Aeronautics and Space Administration Tokyo University of Marine Science and Technology Department of Fisheries and Oceans Canada Woods Hole Oceanographic Institution
    Schlagwort(e): Beaufort Gyre ; Arctic Ocean ; Freshwater balance ; Circulation ; Modeling ; Climate change
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  • 44
    Publikationsdatum: 2022-10-26
    Beschreibung: 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 Geophysical Research Letters 46(16), (2019): 9851-9860, doi:10.1029/2019GL083726.
    Beschreibung: Coral reef calcification is expected to decline due to climate change stressors such as ocean acidification and warming. Projections of future coral reef health are based on our understanding of the environmental drivers that affect calcification and dissolution. One such driver that may impact coral reef health is heterotrophy of oceanic‐sourced particulate organic matter, but its link to calcification has not been directly investigated in the field. In this study, we estimated net ecosystem calcification and oceanic particulate organic carbon (POCoc) uptake across the Kāne'ohe Bay barrier reef in Hawai'i. We show that higher rates of POCoc uptake correspond to greater net ecosystem calcification rates, even under low aragonite saturation states (Ωar). Hence, reductions in offshore productivity may negatively impact coral reefs by decreasing the food supply required to sustain calcification. Alternatively, coral reefs that receive ample inputs of POCoc may maintain higher calcification rates, despite a global decline in Ωar.
    Beschreibung: Data needed for calculations are available in the supporting information. Additional data can be provided upon request directly from the corresponding author or accessed by links provided in the supporting information. The authors declare no competing financial interests. We thank Texas Sea Grant for providing partial funding for this project to A. Kealoha through the Grants‐In‐Aid of Graduate Research Program. We also thank the NOAA Nancy Foster Scholarship for PhD program funding to A. Kealoha and Texas A&M University for funds awarded to Shamberger that supported this work. This research was also supported by funding from National Science Foundation Grant OCE‐1538628 to Rappé. The Hawaii Institute of Marine Biology (particularly the Rappé Lab and Jason Jones), NOAA's Coral Reef Ecosystem Program, Connie Previti, Serena Smith, and Chris Maupin were instrumental in sample collection and data analysis.
    Beschreibung: 2020-02-22
    Schlagwort(e): Coral reefs ; Ocean acidification ; Climate change ; Heterotrophy
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  • 45
    Publikationsdatum: 2022-10-21
    Beschreibung: These data files and MATLAB scripts reproduce the model data and figures as published in Bramante et al. (in prep) Modeling the impacts of a changing climate on cross-shore sediment transport: Kwajalein Atoll, Marshall Islands.
    Beschreibung: Atoll reef islands primarily consist of unconsolidated sediment, and their ocean-facing shorelines are maintained by sediment produced and transported across their reefs. Changes in incident waves can alter cross-shore sediment exchange and thus affect the sediment budget and morphology of atoll reef islands. Here we investigate the influence of sea-level rise and projected wave climate change on wave characteristics and cross-shore sediment transport across an atoll reef at Kwajalein Island, Republic of the Marshall Islands. Using a phase-resolving model, we quantify the influence on sediment transport of quantities not well-captured by wave-averaged models, namely wave asymmetry and skewness and flow acceleration. Model results suggest that for current reef geometry, sea level, and wave climate, potential bedload transport is directed onshore, decreases from the fore reef to the beach, and is sensitive to the influence of flow acceleration. We find that a projected 12% decrease in annual wave energy by 2100 CE has negligible influence on reef flat hydrodynamics. However, 0.5-2.0 m of sea-level rise increases wave heights, skewness, and shear stress on the reef flat, and decreases wave skewness and shear stress on the fore reef. These hydrodynamic changes decrease potential sediment inputs onshore from the fore reef where coral production is greatest, but increase potential cross-reef sediment transport from the outer reef flat to the beach. Assuming sediment production on the fore reef remains constant or decreases due to increasing ocean temperatures and acidification, these processes have the potential to decrease net sediment delivery to atoll islands, causing erosion.
    Beschreibung: This project was supported by the Strategic Environmental Research and Development Program through awards SERDP RC-2334 and RC-2336.
    Schlagwort(e): Climate change ; Sediment transport ; Wave model ; Fringing reef
    Repository-Name: Woods Hole Open Access Server
    Materialart: Dataset
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  • 46
    Publikationsdatum: 2022-05-25
    Beschreibung: 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 Global and Planetary Change 65 (2009): 107-114, doi:10.1016/j.gloplacha.2008.10.013.
    Beschreibung: Increases in the partial pressure of carbon dioxide (pCO2) in the atmosphere will significantly affect a wide variety of terrestrial fauna and flora. Because of tight atmospheric-oceanic coupling, shallow-water marine species are also expected to be affected by increases in atmospheric carbon dioxide concentrations. One proposed way to slow increases in atmospheric pCO2 is to sequester CO2 in the deep sea. Thus, over the next few centuries marine species will be exposed to changing seawater chemistry caused by ocean-atmospheric exchange and/or deep-ocean sequestration. This initial case study on one allogromiid foraminiferal species (Allogromia laticollaris) was conducted to begin to ascertain the effect of elevated pCO2 on benthic Foraminifera, which are a major meiofaunal constituent of shallow- and deep-water marine communities. Cultures of this thecate foraminiferan protist were used for 10-14-day experiments. Experimental treatments were executed in an incubator that controlled CO2 (15 000; 30 000; 60 000; 90 000; 200 000 ppm), temperature and humidity; atmospheric controls (i.e., ~375 ppm CO2) were executed simultaneously. Although the experimental elevated pCO2 values are far above foreseeable surface water pCO2, they were selected to represent the spectrum of conditions expected for the benthos if deep-sea CO2 sequestration becomes a reality. Survival was assessed in two independent ways: pseudopodial presence/absence and measurement of adenosine triphosphate (ATP), which is an indicator of cellular energy. Substantial proportions of A. laticollaris populations survived 200 000 ppm CO2 although the mean of the median [ATP] of survivors was statistically lower for this treatment than for that of atmospheric control specimens. After individuals that had been incubated in 200 000 ppm CO2 for 12 days were transferred to atmospheric conditions for ~24 hours, the [ATP] of live specimens (survivors) approximated those of the comparable atmospheric control treatment. Incubation in 200 000 ppm CO2 also resulted in reproduction by some individuals. Results suggest that certain Foraminifera are able to tolerate deep-sea CO2 sequestration and perhaps thrive as a result of elevated pCO2 that is predicted for the next few centuries, in a high-pCO2 world. Thus, allogromiid foraminiferal “blooms” may result from climate change. Furthermore, because allogromiids consume a variety of prey, it is likely that they will be major players in ecosystem dynamics of future coastal sedimentary environments.
    Beschreibung: This work was funded by US Department of Energy grant # DE-FG02-03ER63696 (to J. Kennett and J. Bernhard), NSF OCE-0725966, and the WHOI Summer Student Fellow Program, which is funded by NSF Research Experience for Undergraduates Program grant #OCE-0139423.
    Schlagwort(e): Allogromia laticollaris ; CO2 injection ; Deep-sea ; Climate change ; Hypercapnia
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  • 47
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Global Change Biology 15 (2009): 2078-2088, doi:10.1111/j.1365-2486.2008.01822.x.
    Beschreibung: Sequestration of carbon dioxide (CO2) in the ocean is being considered as a feasible mechanism to mitigate the alarming rate in its atmospheric rise. Little is known, however, about how the resulting hypercapnia and ocean acidification may affect marine fauna. In an effort to understand better the protistan reaction to such an environmental perturbation, the survivorship of benthic foraminifera, which is a prevalent group of protists, was studied in response to deep-sea CO2 release. The survival response of calcareous, agglutinated, and thecate foraminifera was determined in two experiments at ~3.1 and 3.3 km water depth in Monterey Bay (California, USA). Approximately five weeks after initial seafloor CO2 release, in situ incubations of the live-dead indicator CellTracker Green were executed within seafloor-emplaced pushcores. Experimental treatments included direct exposure to CO2 hydrate, two levels of lesser exposure adjacent to CO2 hydrate, and controls, which were far removed from the CO2 hydrate release. Results indicate that survivorship rates of agglutinated and thecate foraminifera were not significantly impacted by direct exposure but the survivorship of calcareous foraminifera was significantly lower in direct exposure treatments compared to controls. Observations suggest that, if large scale CO2 sequestration is enacted on the deep-sea floor, survival of two major groups of this prevalent protistan taxon will likely not be severely impacted, while calcareous foraminifera will face considerable challenges to maintain their benthic populations in areas directly exposed to CO2 hydrate.
    Beschreibung: This work was funded by the Monterey Bay Aquarium Research Institute (project 200002; to JPB), US Department of Energy grant # DE-FG02-03ER63696 (to J. P. Kennett and J.M.B.), and NSF OCE-0725966 (to J.M.B.).
    Schlagwort(e): Carbon dioxide sequestration ; CO2 injection ; Climate change ; Foraminifera ; Experiment ; Hypercapnia ; Meiofauna ; Monterey Bay ; Ocean acidification ; Protist
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  • 48
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Ecology Letters 11 (2008): 1316-1327, doi:10.1111/j.1461-0248.2008.01251.x.
    Beschreibung: In the short-term heterotrophic soil respiration is strongly and positively related to temperature. In the long-term its response to temperature is uncertain. One reason for this is because in field experiments increases in respiration due to warming are relatively short-lived. The explanations proposed for this ephemeral response include depletion of fast-cycling, soil carbon pools and thermal adaptation of microbial respiration. Using a 〉15 year soil warming experiment in a mid-latitude forest, we show that the apparent ‘acclimation’ of soil respiration at the ecosystem scale results from combined effects of reductions in soil carbon pools and microbial biomass, and thermal adaptation of microbial respiration. Mass specific respiration rates were lower when seasonal temperatures were higher, suggesting that rate reductions under experimental warming likely occurred through temperature-induced changes in the microbial community. Our results imply that stimulatory effects of global temperature rise on soil respiration rates may be lower than currently predicted.
    Beschreibung: This research was supported by the Office of Science (BER), U.S. Department of Energy and the Andrew W. Mellon Foundation.
    Schlagwort(e): Acclimation ; Adaptation ; Soil respiration ; Thermal biology ; Temperature ; Carbon cycling ; Climate change ; Climate warming ; Microbial community ; CO2
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  • 49
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Marine Science 1 (2009): 279-302, doi:10.1146/annurev.marine.010908.163801.
    Beschreibung: Time-series observations form a critical element of oceanography. New interdisciplinary efforts launched in the past two decades complement the few earlier, longer-running time series in building a better, though still poorly-resolved, picture of lower-frequency ocean variability, the climate processes driving it, and its implications for foodweb dynamics, carbon storage and climate feedbacks. Time-series also enlarge our understanding of ecological processes and are integral for improving models of physical-biogeochemical-ecological ocean dynamics. The major time-series observatories go well beyond simple monitoring of core ocean properties, although that important activity forms the critical center of all time-series efforts. Modern ocean time series have major process and experimental components, entrain ancillary programs and have integrated modeling programs for deriving better understanding of the observations and the changing, three-dimensional ocean in which the observatories are embedded.
    Beschreibung: HWD was supported by NSF grant OPP-0217282. SCD was supported by the Center for Microbial Oceanography Research and Education (C-MORE; NSF CCF-424599). DKS was supported by NSF grant OCE-0628444.
    Schlagwort(e): Climate change ; Biogeochemistry ; Plankton ecology ; Carbon cycle
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  • 50
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2007. 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 Energy Policy 35 (2007): 5370-5383, doi:10.1016/j.enpol.2006.01.040.
    Beschreibung: Multiple environmental changes will have consequences for global vegetation. To the extent that crop yields and pasture and forest productivity are affected there can be important economic consequences. We examine the combined effects of changes in climate, increases in carbon dioxide, and changes in tropospheric ozone on crop, pasture, and forest lands and the consequences for the global and regional economies. We examine scenarios where there is limited or little effort to control these substances, and policy scenarios that limit emissions of CO2 and ozone precursors. We find the effects of climate and CO2 to be generally positive, and the effects of ozone to be very detrimental. Unless ozone is strongly controlled damage could offset CO2 and climate benefits. We find that resource allocation among sectors in the economy, and trade among countries, can strongly affect the estimate of economic effect in a country.
    Beschreibung: This research was supported by the US Department of Energy, US Environmental Protection Agency, US National Science Foundation, US National Aeronautics and Space Administration, US National Oceanographic and Atmospheric Administration; and the Industry and Foundation Sponsors of the MIT Joint Program on the Science and Policy of Global Change
    Schlagwort(e): Climate change ; Ozone damage ; Vegetation ; Agriculture ; Economics
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  • 51
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © National Academy of Sciences, 2006. This article is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 103 (2006): 1342-1346, doi:10.1073/pnas.0503198103.
    Beschreibung: Recent observations of changes in some tundra ecosystems appear to be responses to a warming climate. Several experimental studies have shown that tundra plants and ecosystems can respond strongly to environmental change, including warming; however, most studies were limited to a single location and were of short duration and based on a variety of experimental designs. In addition, comparisons among studies are difficult because a variety of techniques have been used to achieve experimental warming and different measurements have been used to assess responses. We used metaanalysis on plant community measurements from standardized warming experiments at 11 locations across the tundra biome involved in the International Tundra Experiment. The passive warming treatment increased plant-level air temperature by 1-3°C, which is in the range of predicted and observed warming for tundra regions. Responses were rapid and detected in whole plant communities after only two growing seasons. Overall, warming increased height and cover of deciduous shrubs and graminoids, decreased cover of mosses and lichens, and decreased species diversity and evenness. These results predict that warming will cause a decline in biodiversity across a wide variety of tundra, at least in the short term. They also provide rigorous experimental evidence that recently observed increases in shrub cover in many tundra regions are in response to climate warming. These changes have important implications for processes and interactions within tundra ecosystems and between tundra and the atmosphere.
    Beschreibung: The projects represented here were supported by many sources, including the National Science Foundation, Swedish Natural Science Research Council, United Kingdom Natural Environment Research Council, Natural Sciences and Engineering Research Council of Canada, Research Council of Norway, Icelandic Centre for Research, and the Academy of Finland. Coordination of activities was made possible with support from the Bonanza Creek Long-Term Ecological Research site.
    Schlagwort(e): Arctic and alpine ecosystems ; Biodiversity ; Climate change ; Vegetation change
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 52
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © American Geophysical Union, 2006. 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 42 (2006): W03426, doi:10.1029/2005WR004131.
    Beschreibung: We assessed the effects of historical (1931-1998) changes in both land-use and climate on the water budget of a rapidly urbanizing watershed, Ipswich River basin (IRB), in northeastern Massachusetts. Water diversions and extremely low flow during summer are major issues in the IRB. Our study centers on a detailed analysis of diversions and a combined empirical/modeling treatment of evapotranspiration (ET) response to changes in climate and land-use. A detailed accounting of diversions showed that net diversions increased due to increases in water withdrawals (primarily ground water pumping) and export of sewage. Net diversions constitute a major component of runoff (20% of streamflow). Using a combination of empirical analysis and physically based modeling we related an increase in precipitation (2.7 mm/yr) and changes in other climate variables to an increase in ET (1.7 mm/yr). Simulations with a physically based water-balance model showed that the increase in ET could be attributed entirely to a change in climate, while the effect of land-use change was negligible. The land-use change effect was different from ET and runoff trends commonly associated with urbanization. We generalized these and other findings to predict future streamflow using climate change scenarios. Our study could serve as a framework for studying suburban watersheds, being the first study of a suburban watershed that addresses long-term effects of changes in both land-use and climate, and accounts for diversions and other unique aspects of suburban hydrology.
    Beschreibung: This research was partially supported by NSF grants (DEB-9726862, OCE-9726921 and OCE-0423565).
    Schlagwort(e): Water budgets ; Evapotranspiration ; Climate change ; Land-use change ; Urbanization ; Water-balance model ; Ipswich River
    Repository-Name: Woods Hole Open Access Server
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  • 53
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Global Change Biology 12 (2006): 731-750, doi:10.1111/j.1365-2486.2006.01113.x.
    Beschreibung: In terrestrial high-latitude regions, observations indicate recent changes in snow cover, permafrost, and soil freeze-thaw transitions due to climate change. These modifications may result in temporal shifts in the growing season and the associated rates of terrestrial productivity. Changes in productivity will influence the ability of these ecosystems to sequester atmospheric CO2. We use the Terrestrial Ecosystem Model (TEM), which simulates the soil thermal regime, in addition to terrestrial carbon, nitrogen and water dynamics, to explore these issues over the years 1960-2100 in extratropical regions (30°-90°N). Our model simulations show decreases in snow cover and permafrost stability from 1960 to 2100. Decreases in snow cover agree well with NOAA satellite observations collected between the years 1972-2000, with Pearson rank correlation coefficients between 0.58-0.65. Model analyses also indicate a trend towards an earlier thaw date of frozen soils and the onset of the growing season in the spring by approximately 2-4 days from 1988-2000. Between 1988 and 2000, satellite records yield a slightly stronger trend in thaw and the onset of the growing season, averaging between 5-8 days earlier. In both the TEM simulations and satellite records, trends in day of freeze in the autumn are weaker, such that overall increases in growing season length are due primarily to earlier thaw. Although regions with the longest snow cover duration displayed the greatest increase in growing season length, these regions maintained smaller increases in productivity and heterotrophic respiration than those regions with shorter duration of snow cover and less of an increase in growing season length. Concurrent with increases in growing season length, we found a reduction in soil carbon and increases in vegetation carbon, with greatest losses of soil carbon occurring in those areas with more vegetation, but simulations also suggest that this trend could reverse in the future. Our results reveal noteworthy changes in snow, permafrost, growing season length, productivity, and net carbon uptake, indicating that prediction of terrestrial carbon dynamics from one decade to the next will require that large-scale models adequately take into account the corresponding changes in soil thermal regimes.
    Beschreibung: Funds were provided by the NSF for the Arctic Biota/Vegetation portion of the ‘Climate of the Arctic: Modeling and Processes’ project (OPP- 0327664), and by the USGS ‘Fate of Carbon in Alaska Landscapes’ project.
    Schlagwort(e): Growing season ; Carbon sequestration ; Productivity ; Respiration ; Snow cover ; Permafrost ; Climate change ; Terrestrial ecosystem model
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  • 54
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Journal of Ecology 94 (2006): 740-753, doi:10.1111/j.1365-2745.2006.01139.x.
    Beschreibung: Soils of tundra and boreal ecosystems contain large organic matter stocks, typically as a layer of peat that blankets the underlying mineral soil. Despite the low productivity of northern vegetation, organic matter accumulates as peat because decomposition of plant litter is limited by low soil temperatures and often wet, anaerobic conditions (Heal et al. 1981, Jonasson et al. 2001). The total C storage in this northern peat is globally significant, accounting for about one third of the global soil C stock if one includes both tundras and boreal forests (Oechel and Billings 1992, Callaghan et al. 2004a). Soils of northern ecosystems also contain large amounts of organic N that is currently unavailable to plants, but is potentially available and could support higher productivity if mineralized (Shaver et al. 1991, Nadelhoffer et al. 1992, Weintraub and Schimel 2005 a). Controls on soil C stocks and turnover, therefore, are key issues for understanding C exchanges between northern ecosystems and the atmosphere. In this paper, we determine how C losses from peaty soil organic matter are related to its chemical composition, and how that composition changes as the organic matter decomposes. To address these issues we compared four soil organic matter types from three tundra ecosystems near Toolik Lake, Alaska. The comparison included both unfertilized soils and soils that were fertilized annually for eight years before sampling. Under laboratory conditions, we determined how temperature and moisture conditions affect C losses from these organic matter types. The experiment also allowed us to determine how the chemical composition of different types of organic matter changed over four simulated “seasons” of decomposition. The chemical composition or “quality” of soil organic matter is a useful predictor of C turnover (Ågren and Bosatta 1996) although a wide range of definitions and fractionation schemes have been used (Sollins et al. 1999, Harmon and Lajtha 1999). In general, high-quality organic matter is defined as that which is more readily processed by microbes and has a higher rate of decomposition. Fresh plant litter and newly-formed organic matter are expected to be of higher quality than older, more fully decomposed organic matter in which the more labile components have been metabolized (Aerts 1997, Berg 2000). Species composition of the vegetation may also have a strong influence on litter and organic matter “quality” (Berendse 1994, Cornelissen 1996, Hobbie 1996, Hobbie and Gough 2004). In this research we characterized organic matter quality with a widely used sequential extraction procedure (Ryan et al. 1990, Harmon and Lajtha 1999) that breaks soil organic matter into 4 fractions: (1) a “non-polar extractable” (NPE) fraction extracted in methylene chloride, (2) a “water-soluble” (WS) fraction extracted in boiling water, (3) an “acid-soluble’ (AS) fraction extracted in H2SO4, and (4) an “acid-insoluble” (AIS) residue.
    Beschreibung: This research was supported by grants from the US National Science Foundation’s Division of Environmental Biology and Office of Polar Programs to the Marine Biological Laboratory.
    Schlagwort(e): Soil organic matter ; Soil carbon ; Peat ; Organic matter quality ; Proximate carbon fractions ; Decomposition ; Soil respiration ; Tundra ; Alaska ; Climate change ; Greenhouse warming
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  • 55
    Publikationsdatum: 2021-05-19
    Beschreibung: Coral records from coastal East Africa spanning 2° to 7°S (Kiwayu, Malindi, Watamu, Mombasa, Kisite, and Mafia) demonstrate that isotopic tracers preserved within coral aragonite accurately record intraseasonal to interannual changes in sea surface temperature. The strong seasonal signal observed at all six sites most likely reflects sea surface temperature variability forced by ocean circulation and reversals in wind direction associated with the Indo-African Monsoon. Strong southwesterly winds during the Southwest Monsoon initiate evaporative cooling and mixing, resulting in a sea surface temperature minimum in the late boreal summer. Coral δ180 values are higher during this period. Reproducibility in the coral δ180 signal between sites indicates that an individual coral isotope records from the coast of East Africa can be used to reconstruct regional climatic conditions. We present the first multisite analysis of sea surface temperature variability along the East African coast as recorded in the isotopic composition of reef corals.
    Beschreibung: Published
    Schlagwort(e): Climate change ; Coral reefs ; Environmental impact
    Repository-Name: AquaDocs
    Materialart: Proceedings Paper , Non-Refereed
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  • 56
    Publikationsdatum: 2021-05-19
    Beschreibung: Chapter Three of the Africa Environment Outlook Report is concerned with the impact of environmental change on human vulnerability. The Report considers vulnerability in the context of exposure to environmental hazards (contingencies, shocks and stresses) and the coping capabilities of people. In this case study, we will show that the Maasai of Kajiado district in Kenya (as well as other pastoralists) face two distinct types of environmental hazards. The first includes climatic uncertainty and drought. The second hazard consists of the environmental changes driven by shifts in land use patterns. Whereas the Maasai have well developed and intricate strategies for coping with the first type of environmental hazard, the impact of the second set of hazards has seriously diminished their ability to cope using traditional strategies. As a result, they have become increasingly vulnerable to droughts. They have responded with a set of alternative strategies, which have cushioned a portion of the community from environmental shocks, while leaving the rest more vulnerable than ever.
    Schlagwort(e): Climate change ; Pastoralism ; Droughts
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  • 57
    Publikationsdatum: 2021-05-19
    Beschreibung: A central finding of the ocean drilling expedition off Namibia and South Africa (Leg 175, 1997) is that the history of the intense coastal upwelling in that region is intimately tied into global climate change and the geochemistry of the deep ocean. The high productivity associated with this flow of cool, nutrient-dense deep water upwards along the coast cannot simply be described as a progressive increase of productivity that began ten million years ago. Instead, physical upwelling of cold water follows global cooling rather closely, while silicate content of the water (crucial for diatom production) runs out of phase with upwelling but is highly correlated with changes in thermohaline circulation.
    Beschreibung: Unpublished
    Schlagwort(e): Climate change ; Coastal upwelling
    Repository-Name: AquaDocs
    Materialart: Working Paper , Non-Refereed
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  • 58
    Publikationsdatum: 2021-05-19
    Beschreibung: This report is the result of a brief study that has been carried out in the period December 2003 to February 2004 by Jaap Arntzen, Pauline Dube and Martin Muchero for the Programme Office of the Global Environmental Change and Food Systems Programme,UK.
    Beschreibung: Global Environmental Change and Food Systems Programme - ESSP
    Schlagwort(e): Climate change ; Food supply ; Environmental impact
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  • 59
    Publikationsdatum: 2021-05-19
    Beschreibung: The mean temperature on the planet is increasing. The rate of this increase appears to be accelerating and is at present approximately 2 degrees per century. 1998 was the warmest year since temperature recordings started some 150 years ago. Similarly the 1990s was the warmest decade. In addition, 1997 and 1998 saw the strongest El Niño ever recorded. As a consequence of this, very high water temperatures were observed in many parts of the oceans, particularly in the tropical areas. Due to the high water temperatures, the corals over much of the world bleached and subsequently died. In 1997–98, massive mortality occurred particularly among corals of the Indian Ocean. The reefs of Sri Lanka, Maldives, India, Kenya, Tanzania, and Seychelles were particularly hard hit, with mortalities of up to 95%. Reefs in other parts of the Indian Ocean showed mortality rates up to 50%. Hence the coral mortality during 1998 was the unprecedented in severity. The secondary effects on the socio-economic condition in the coastal communities of the Indian Ocean are presently studied as a part of the CORDIO Program (Coral Reef Degradation of the Indian Ocean).
    Beschreibung: Published
    Schlagwort(e): Climate change ; Coral reefs
    Repository-Name: AquaDocs
    Materialart: Report , Non-Refereed
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  • 60
    Publikationsdatum: 2021-05-19
    Beschreibung: The world’s climate is changing and will continue to change into the coming century at rates projected to be unprecedented in recent human history. The risks associated with these changes are real but highly uncertain. Societal vulnerability to the risks associated with climate change may exacerbate ongoing social and economic challenges, particularly for those parts of societies dependent on resources that are sensitive to changes in climate. Risks are apparent in agriculture, fisheries and many other components that constitute the livelihood of rural populations in developing countries. In this paper we explore the nature of risk and vulnerability in the context of climate change and review the evidence on present-day adaptation in developing countries and on coordinated international action on future adaptation. We argue that all societies are fundamentally adaptive and there are many situations in the past where societies have adapted to changes in climate and to similar risks. But some sectors are more sensitive and some groups in society more vulnerable to the risks posed by climate change than others. Yet all societies need to enhance their adaptive capacity to face both present and future climate change outside their experienced coping range. The challenges of climate change for development are in the present – observed climate change, present-day climate variability and future expectations of change are changing the course of development strategies – development agencies and governments are now planning for this adaptation challenge. The primary challenge, therefore, posed at both the scale of local natural resource management and at the scale of international agreements and actions, is to promote adaptive capacity in the context of competing sustainable development objectives.
    Beschreibung: Published
    Schlagwort(e): Adaptations ; Vulnerability ; Climate change ; Environmental policy ; Climate change ; Developing countries
    Repository-Name: AquaDocs
    Materialart: Journal Contribution , Refereed , Article
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  • 61
    Publikationsdatum: 2021-05-19
    Beschreibung: This report presents the integrated case study for Egypt carried out under an OECD project on Development and Climate Change. The report is structured around a three-tiered framework. First, recent climate trends and climate change scenarios for Egypt are assessed and key sectoral impacts are identified and ranked along multiple indicators to establish priorities for adaptation. Second, donor portfolios are analyzed to examine the proportion of development assistance activities affected by climate risks. A desk analysis of donor strategies and project documents as well as national plans is conducted to assess the degree of attention to climate change concerns in development planning and assistance. Third, an in-depth analysis is conducted for coastal zones as well as water resource management on the Nile. Given that Egypt’s population, land-use and agriculture, as well as its economic activity are all constrained along a narrow T-shaped strip of land along the Nile and the deltaic coast, it is extremely vulnerable to any adverse impacts on its coastal zones and water availability from the Nile. Climate change poses significant risks through sea level rise on the costal zone, which is already subsiding at approximately 3-5mm/year around the Nile delta. Analyses of current climatic trends reveal a warming trend in recent decades with country averaged mean temperature increases of 1.4°C and 2.5°C projected by 2050 and 2100. Higher temperatures in the semi-arid regions with resulting evaporative losses coupled with increasing water demands will likely result in decreasing water availability from the Nile. There is also some possibility of significant decline in Nile streamflow under climate change as a result of changes in precipitation, although the studies reviewed in this report offer conflicting results. Coastal zone and water resource impacts have also serious implications for agriculture: sea level rise will adversely impact prime agricultural land in the Nile delta through inundation and salinization, while the intensive irrigated agriculture upstream would suffer from any reductions in Nile water availability. Therefore, climate change is a serious development concern for Egypt. Egypt receives around $1.5 billion dollars of Official Development Assistance (ODA) annually. Analysis of donor portfolios for the country using the OECD-World Bank Creditor Reporting System (CRS) database reveals that roughly 33% of development assistance (by aid amount) or 25% of donor projects (by number) are in sectors potentially affected by climate change risks. These numbers are only indicative, and the reader is referred to the main report for a more nuanced interpretation. In general, donor strategies do not mention climate change – although several stress the concern for water scarcity in Egypt. Some donor strategies and projects explicitly cater to improved water management and conservation in Egypt. While not explicitly recognizing climate change, any measures to promote efficiency of water use would be synergistic with adaptation to the additional stresses on water availability posed by climate change. In addition, there are a few donor projects on coastal zones. The absence of climate change concerns in these projects however could be a significant omission, given the local subsidence at several locations on Egypt’s coast, which would exacerbate the impacts of climate change induced sea level rise and saline intrusion. Regarding climate change concerns in national planning, despite existing institutions and assessments, actual implementation of adaptation measures is faced with several obstacles, including other pressing development priorities such as increasing costs of living, loss of land productivity, as well as inefficient economic policies such as the heavy subsidies for water, which make its conservation difficult. The in-depth analysis in this report, which focuses on Egypt’s coastal zones and the Nile water resources, show that Egypt has already conducted fairly rigorous coastal zones vulnerability and impact assessments and has already started several coastal protection activities to improve the resilience to sealevel rise. However, such actions are largely restricted to “hard” adaptation, and – relative to the magnitude of the problem – are still fairly limited in their coverage of vulnerable areas. Thus, there is both a need for greater coverage of vulnerability assessment and coastal protection activities, as well as to broaden the portfolio of responses beyond hard adaptation. In particular, there is a need to directly address several development and demographic pressures that exacerbate coastal vulnerability – particularly coastal pollution. There is also a need to better implement existing laws that reduce coastal vulnerability and the formulation of new regulations that correct distortions and other activities which might exacerbate coastal vulnerability to sea level rise. Adaptation options for Egypt’s water resources meanwhile are closely intertwined with Egypt’s development choices and pathways. Any changes in water supply due to climate change over the medium term will occur alongside the certainty of increased demographic pressures (the national population is growing by 1 million every nine months) as well as the potential increases in Nile water abstractions by the upstream riparian countries. Adapting to climate change will have close resonance with adapting to water scarcity and is likely to require implementation of water demand management strategies which may require capacity building and awareness raising across institutions and society. Adaptation measures on the supply-side include ways to improve rain-harvesting techniques, increasing extraction of ground water, water recycling, desalination, and improving water transportation. In addition, regular reviewing and updating of drought responses and research into improved long-term forecasting is essential to enhance Egypt’s ability to cope with prolonged drought. This case study also highlights the importance of the trans-boundary dimension in addressing climate change adaptation, given the need for dialog and cooperation among the Nile Basin states to address both technical issues such as sharing of data, as well as more political and sensitive ones such as water allocation. The recently established Nile Basin Initiative (NBI) is a first step. If successfully implemented, such an initiative can help reconcile the water use and development priorities of all riparian countries, including their capacity to adapt to any reductions or other changes in Nile flows from climate change. However, it is too early to assess the effectiveness of the NBI, given that it has been in existence for only a few years. Nevertheless, it marks an important beginning in terms of providing a cooperative forum to reconcile the water needs, development aspirations, and climate change concerns, not only of Egypt but of all the Nile Basin countries.
    Beschreibung: OECD
    Beschreibung: Unpublished
    Schlagwort(e): Climate change ; Coastal zone
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    Materialart: Working Paper , Non-Refereed
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  • 62
    facet.materialart.
    Unbekannt
    Ministry of Environment and Transport, Republic of Seychelles
    Publikationsdatum: 2021-01-30
    Beschreibung: The Republic of Seychelles acceded to the United Nations Framework Convention on Climate Change (UNFCCC) on the 22nd September 1992, being the second country to do so. Likewise, the Seychelles was one of the earliest countries to sign the Kyoto Protocol on the 20th March 1998. The Initial National Communication to the UNFCCC by the Seychelles reflects our continued commitment to the process. Although the guidelines provided for the preparation of initial national communications by non-Annex I Parties do not place much emphasis on issues of vulnerability, adaptation and capacity building, my country is convinced that without sufficient attention given to these issues many small island states will not be able to cope with the impacts of climate change. The preparation of the National Communication enabled us to focus on issues that link climate change to sustainable development, which were not given much attention before. The process created awareness at all levels of government, local communities, NGOs and the private sector, making it a truly integrated and highly participatory engagement. Through the work of the National Climate Change Committee (NCCC) and the study teams, which involved broad participation, several studies and assessments were undertaken in order to ensure that this Communication reflects clearly our situation, constraints and circumstances. The Communication further reinforces our position as an insignificant emitter and a net sink of greenhouse gas. Nevertheless, we have also identified areas for mitigation, for which we are prepared to undertake consistent and meaningful actions. Whilst the world continues to debate about global climate change and its effects, small islands like the Seychelles are the most vulnerable, with increased potential loss of coastal infrastructure due to sea-level rise. The socio-economic implications are enormous. Amidst the range of uncertainties and the inability for science to provide all the immediate answers, it is important that we build upon two principles adopted in Rio (1992) and Kyoto (1997), respectively. The ‘the precautionary principle’, emphasises that all countries urgently need to identify areas where they can reduce GHG emissions through changes in policy and technology. Secondly, whilst it is clear that climate change will occur despite measures adopted in the Kyoto Protocol, there is an urgent need to ensure that developing nations, including Small Island Developing States (SIDS), can continue to develop and prosper in an equitable manner. Thus, SIDS need to be fully equipped, both financially and technically, to adapt to global climate change and sea-level rise, without re-directing its limited resources from sustainable development and the eradication of poverty, which is still imminent in many island states. It is, therefore, my sincere wish that this Communication has not only fulfilled our requirements under Article 12 of the Convention, but also provided a better understanding of the specific challenges faced and the efforts that have been made by my country in coping with the increasing threat of global climate change.
    Beschreibung: Published
    Schlagwort(e): Climate change
    Repository-Name: AquaDocs
    Materialart: Proceedings Paper , Non-Refereed
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  • 63
    facet.materialart.
    Unbekannt
    Ministry of Environment of the Federal Republic of Nigeria.
    Publikationsdatum: 2021-01-30
    Beschreibung: Nigeria with a total area of 923,800 sq km occupies about 14% of land area in West Africa. The country lies between 4oN and 14oN, and between 3oE and 15oE. It is bordered respectively in the north, east, and west by Niger, the Cameroon, and Benin Republic, while the Gulf of Guinea, an arm of the Atlantic Ocean, forms the southern border. Most of Nigeria is covered with Pre- Cambrian rocks, but there are also metamorphic and sedimentary rocks of Eocene times as well as volcanic rocks. In general, three types of geologic structures exist in Nigeria, namely, areas of uplift, basins of sedimentation, and isolated volcanic areas. The areas of uplift are made up of the oldest rocks in Nigeria - the basement complex rocks. The basins of sedimentation are the down-warped areas, which were drowned by the sea at different times and in which sediments eroded from the areas of uplift were laid down.
    Beschreibung: Published
    Schlagwort(e): Climate change ; Environmental effects
    Repository-Name: AquaDocs
    Materialart: Report , Non-Refereed
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  • 64
    Publikationsdatum: 2021-01-30
    Beschreibung: The studies made in the context of this Initial National Communication on Climate Change are based on the findings of the Intergovernmental Panel on Climate Change (IPCC) 1 study on impacts and adaptation of Indian Ocean small island states. Changes in climate to be anticipated in Comoros by year 2050 are estimated to be a raise in mean annual air temperature to an average of 28°C, a change that represents a 1°C increase compared to the current situation. A sea level increase of 4 mm/year for a total increase of 20 cm by 2050 is also expected. Expected impacts are the intrusion of salted water in the coastal aquifers; an increase in the occurrence of malaria and of collective food poisoning resulting from consumption of marine animals 2; a decrease in crop yields, agricultural production and fisheries; the displacement of 10% of the country’s coastal inhabitants whose habitat would be flooded; and lastly, the destruction of coastal infrastructure and habitat for an estimated value of 400 million USD, 2.2 times Comoros Gross Domestic product (GDP) for 2001. Vulnerability and adaptation assessment studies were made for agriculture, coastal infrastructure and resources, health, and water.
    Beschreibung: Unpublished
    Schlagwort(e): Climate change ; Environmental effects
    Repository-Name: AquaDocs
    Materialart: Working Paper , Non-Refereed
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  • 65
    Publikationsdatum: 2021-05-19
    Beschreibung: Anticipated global warming as a result of the emission of greenhouse gases into the atmosphere was the most important subject discussed during the fifteenth session of the Governing Council of UNEP and at the Second World Climate Conference. The so-called greenhouse effect is a most pressing environmental problem to the extent that it involves many scientific disciplines and hence presents major challenges. The greenhouse gases (CO2,' CFCs, CH4, N2O, O3, etc.) have the effect of changing the atmosphere's radiative balance by trapping more heat near the earth's surface resulting in a rise in global mean surface temperature. It is now clear that if the burning of fossil fuel continues at the present rate, global warming is a virtual certainty.
    Beschreibung: Published
    Schlagwort(e): Climate change ; Global warming
    Repository-Name: AquaDocs
    Materialart: Report , Non-Refereed
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  • 66
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of National Academy of Sciences of the USA for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of the United States of America 102 (2005): 11201-11206, doi:10.1073/pnas.0504949102.
    Beschreibung: Climate change is expected to influence the capacities of the land and oceans to act as repositories for anthropogenic CO2 and hence provide a feedback to climate change. A series of experiments with the National Center for Atmospheric Research–Climate System Model 1 coupled carbon–climate model shows that carbon sink strengths vary with the rate of fossil fuel emissions, so that carbon storage capacities of the land and oceans decrease and climate warming accelerates with faster CO2 emissions. Furthermore, there is a positive feedback between the carbon and climate systems, so that climate warming acts to increase the airborne fraction of anthropogenic CO2 and amplify the climate change itself. Globally, the amplification is small at the end of the 21st century in this model because of its low transient climate response and the near-cancellation between large regional changes in the hydrologic and ecosystem responses. Analysis of our results in the context of comparable models suggests that destabilization of the tropical land sink is qualitatively robust, although its degree is uncertain.
    Beschreibung: This work was supported by National Science Foundation (NSF) Grant NSF ATM-9987457, National Aeronautics and Space Administration (NASA) EOS-IDS Grant NAG5-9514, NASA Carbon Cycle Program Grant NAG5-11200, the Laboratory Directed Research and Development Program of the Lawrence Berkeley National Laboratory, and the Ocean and Climate Change Institute of the Woods Hole Oceanographic Institution.
    Schlagwort(e): Carbon dioxide ; Climate change ; Land carbon sink ; Ocean carbon sink
    Repository-Name: Woods Hole Open Access Server
    Materialart: Preprint
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