A5071017156- Arctic and Antarctic ice dynamics
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Marine and fisheries research
- Geology and Paleoclimatology Research
- Food Industry and Aquatic Biology
- Marine animal studies overview
- Marine Bivalve and Aquaculture Studies
- Climate change and permafrost
- Oceanographic and Atmospheric Processes
- Glioma Diagnosis and Treatment
- Cryospheric studies and observations
- Geological Studies and Exploration
- Marine and environmental studies
- Radiomics and Machine Learning in Medical Imaging
- Radioactive contamination and transfer
- Soil and Water Nutrient Dynamics
- Hydrology and Watershed Management Studies
- Arctic and Russian Policy Studies
- Ocean Acidification Effects and Responses
- Groundwater and Isotope Geochemistry
- Marine and coastal plant biology
- Atmospheric and Environmental Gas Dynamics
University of Maryland Center for Environmental Science
2015-2024
University of Maryland, College Park
2010-2024
Northwestern University
2024
University of Mary
2018
Clark University
2018
Instytut Oceanologii Polskiej Akademii Nauk
2018
Polish Academy of Sciences
2018
Underground Systems (United States)
2017
Grand Junction VA Medical Center
2017
Oceanography Society
2015
Until recently, northern Bering Sea ecosystems were characterized by extensive seasonal sea ice cover, high water column and sediment carbon production, tight pelagic-benthic coupling of organic production. Here, we show that these are shifting away from characteristics. Changes in biological communities contemporaneous with shifts regional atmospheric hydrographic forcing. In the past decade, geographic displacement marine mammal population distributions has coincided a reduction benthic...
Nitrous oxide (N(2)O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading river networks potentially important source of N(2)O via microbial denitrification converts N dinitrogen (N(2)). The fraction denitrified escapes as rather than N(2) (i.e., the yield) an determinant how much produced by networks, but little known about yield in flowing waters. Here, we present results whole-stream (15)N-tracer additions...
Summary 1. Rates of whole‐system metabolism (production and respiration) are fundamental indicators ecosystem structure function. Although first‐order, proximal controls well understood, assessments the interactions between distal controls, such as land use geographic region, lacking. Thus, influence on stream across regions is unknown. Further, there limited understanding how may alter variability in regions. 2. Stream was measured nine streams each eight ( n = 72) United States Puerto...
As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release offset by increased production Arctic boreal biomass; however, lack robust estimates net balance increases risk further overshooting international emissions targets. Precise empirical or model-based assessments critical factors driving are unlikely in near future, so address gap, we present from 98...
We present new flow‐weighted data for δ 18 O H2O , dissolved organic carbon (DOC), barium and total alkalinity from the six largest Arctic rivers: Ob', Yenisey, Lena, Kolyma, Yukon Mackenzie. These data, which can be used to trace runoff, are based upon coordinated collections between 2003 2006 that were temporally distributed capture linked seasonal dynamics of river flow tracer values. Individual samples indicate significant variation in contributions each makes Ocean. Use these estimates...
We measured uptake length of 15 NO 3 − in 72 streams eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls length. As part Lotic Intersite Nitrogen eXperiment II project, we chose nine each region corresponding natural (reference), suburban‐urban, agricultural land uses. Study spanned a range human use maximize variation concentration, geomorphology, metabolism. tested causal model predicting using structural equation modeling. The...
We measured denitrification rates using a field 15 NO 3 − tracer‐addition approach in large, cross‐site study of nitrate uptake reference, agricultural, and suburban‐urban streams. 49 72 streams studied. Uptake length due to ( S Wden n) ranged from 89 m 184 km (median 9050 m) there were no significant differences among regions or land‐use categories, likely because the wide range conditions within each region land use. N 2 production far exceeded O all The fraction total removal water 0.5%...
We measured denitrification and total nitrate uptake rates in a small stream (East Fork of Walker Branch eastern Tennessee) using new field 15 N tracer addition modeling approach that quantifies these for entire reaches. The experiment consisted an 8‐h 99 atom% K NO 3 conservative solute tracer. Two experiments were performed on consecutive days, the first under ambient − concentrations (23 µg L −1 ) second with approximately 500 . fit first‐order two‐box models to longitudinal measurements...
Flow‐weighted dissolved organic carbon (DOC) concentrations and δ 18 O values were determined from major arctic rivers, specifically the Ob, Yenisey, Lena, Kolyma, Mackenzie, Yukon during 2003–2004. These data considered in conjunction with marine for DOC, values, nutrients, salinity, fluorometric indicators of DOC obtained sampling at shelf‐basin boundary Chukchi Beaufort seas. On basis these data, freshwater sampled waters is likely derived regional sources, such as Bering Strait inflow,...
Calcium carbonate (CaCO 3 ) mineral saturation states for aragonite (Ω and calcite are calculated waters of the Chukchi Sea shelf Canada Basin western Arctic Ocean during Shelf‐Basin Interactions project from 2002 to 2004. On shelf, a strong seasonality vertical differentiation was observed. During summertime sea ice retreat period, high rates phytoplankton primary production net community act increase Ω surface waters, while subsurface become undersaturated with respect due primarily...
The eastern Alaska Beaufort Sea coast is characterized by numerous shallow (2–5 m) estuarine lagoons, fed streams and small rivers that drain northward from the Brooks Range through arctic coastal plain, bounded seaward barrier islands shoals. Millions of birds six continents nest forage during summer period in this region using river deltas, shoreline along with several species anadromous marine fish. We examined biogeochemical processes linking benthic community to overall food web...
Seawater nutrient, salinity, and oxygen 18 data collected from 1990 to 1993 in the Bering Chukchi Seas were used identify potential sources of nutrients water masses that result formation Arctic Ocean upper halocline its associated nutrient maximum. Water matching δ O values containing sufficient, or a nearly salinity concentration was subsurface waters summer portions Sea, particularly Gulf Anadyr. However, concentrations significantly declined this north flowing over shallow continental...
A large portion of terrestrial carbon (C) resides in soil organic (SOC). The dynamics this reservoir depend on many factors, including climate. Measurements 13C:12C ratios, C concentrations, and C:N ratios at six forest sites the Southern Appalachian Mountains (USA) were used to explore several hypotheses concerning relative importance factors that control matter (SOM) decomposition SOC turnover. Mean δ13C values increased with depth decreasing concentrations along a continuum from fresh...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 291:135-150 (2005) - doi:10.3354/meps291135 Organic matter pathways zooplankton and benthos under pack ice in late winter open water summer north-central Bering Sea James R. Lovvorn1,*, Lee W. Cooper2, Marjorie L. Brooks1, Christopher C. De Ruyck1, Joseph K. Bump1,3, Jacqueline M. Grebmeier2 1Department of...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMobility of natural organic matter in a study aquiferJohn F. McCarthy, Thomas M. Williams, Liyuan Liang, Philip Jardine, Louwanda W. Jolley, David L. Taylor, Anthony V. Palumbo, and Lee CooperCite this: Environ. Sci. Technol. 1993, 27, 4, 667–676Publication Date (Print):April 1, 1993Publication History Published online1 May 2002Published inissue 1 April...