Now showing items 1-10 of 295
Using indirect methods to constrain symbiotic nitrogen fixation rates : a case study from an Amazonian rain forest
Human activities have profoundly altered the global nitrogen (N) cycle. Increases in anthropogenic N have had multiple effects on the atmosphere, on terrestrial, freshwater and marine ecosystems, and even on human health. ...
Importance of carbon-nitrogen interactions and ozone on ecosystem hydrology during the 21st century
(American Geophysical Union, 2009-03-18)
There is evidence that increasing CO2 concentrations have reduced evapotranspiration and increased runoff through reductions in stomatal conductance during the twentieth century. While this process will continue to counteract ...
Land carbon sequestration within the conterminous United States : regional- and state-level analyses
(John Wiley & Sons, 2015-02-28)
A quantitative understanding of the rate at which land ecosystems are sequestering or losing carbon at national-, regional-, and state-level scales is needed to develop policies to mitigate climate change. In this study, ...
Contributions of long-term research and time-series observations to marine ecology and biogeochemistry
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 ...
Ecosystem feedbacks and cascade processes : understanding their role in the responses of Arctic and alpine ecosystems to environmental change
Global environmental change, related to climate change and the deposition of airborne N-containing contaminants, has already resulted in shifts in plant community composition among plant functional types in arctic and ...
Long-term studies of the marine ecosystem along the west Antarctic Peninsula
Articles in this volume focus on longer-term studies of the marine ecosystem of the continental shelf west of the Antarctic Peninsula, principally by the Palmer, Antarctica Long- Term Ecological Research project (Ross ...
Global N removal by freshwater aquatic systems using a spatially distributed, within-basin approach
(American Geophysical Union, 2008-06-20)
We explored the role of aquatic systems in the global N cycle using a spatially distributed, within-basin, aquatic nitrogen (N) removal model, implemented within the Framework for Aquatic Modeling in the Earth System ...
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Seasonal variability of δ13C and δ15N of fish and squid in the Cabo Frio upwelling system of the southwestern Atlantic
To determine whether shifts occurred in the food web associated with upwelling at the Brazilian western boundary South Atlantic Central Water (SACW), we measured isotopic composition (δ15N and δ13C) of 38 fish and 3 squid ...
Climate and species affect fine root production with long-term fertilization in acidic tussock tundra near Toolik Lake, Alaska
Long-term fertilization of acidic tussock tundra has led to changes in plant species composition, increases in aboveground production and biomass and substantial losses of soil organic carbon (SOC). Root litter is an ...