A5001260404- Soil Carbon and Nitrogen Dynamics
- Atmospheric and Environmental Gas Dynamics
- Soil and Water Nutrient Dynamics
- Plant Water Relations and Carbon Dynamics
- Peatlands and Wetlands Ecology
- Soil and Unsaturated Flow
- Forest ecology and management
- Conservation, Biodiversity, and Resource Management
- Fire effects on ecosystems
- Ecology and Vegetation Dynamics Studies
- Atmospheric chemistry and aerosols
- Groundwater and Isotope Geochemistry
- Phosphorus and nutrient management
- Forest Management and Policy
- Hydrology and Watershed Management Studies
- Soil Management and Crop Yield
- Geology and Paleoclimatology Research
- Agriculture Sustainability and Environmental Impact
- Climate Change Policy and Economics
- Plant responses to elevated CO2
- Soil Geostatistics and Mapping
- Land Use and Ecosystem Services
- Remote Sensing in Agriculture
- Amazonian Archaeology and Ethnohistory
- Isotope Analysis in Ecology
University of Maryland Center for Environmental Science
2016-2025
University of California System
2011-2025
University of Windsor
2024
Lincoln University
2023
University of Maryland, College Park
2019-2023
University of Oklahoma
2021
ORCID
2020
Woodwell Climate Research Center
2009-2018
University of Arizona
2016
Instituto de Pesquisa Ambiental da Amazônia
2003-2015
Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe North America. This paper assesses evidence from field experiments for N effects thresholds terrestrial protection across latitudinal range main categories ecosystems, arctic boreal systems tropical forests. Current thinking on the mechanisms diversity, global distribution G200 ecoregions, current future (2030) estimates atmospheric N-deposition rates are then used identify...
Abstract Variation in soil temperature can account for most of the seasonal and diel variation CO 2 efflux, but effect is not always consistent, other factors such as water content are known to influence respiration. The objectives this research were study spatial temporal respiration a temperate forested landscape evaluate functions predictors Soil fluxes measured with chambers throughout an annual cycle six areas at Harvard Forest central Massachusetts that include drainage classes from...
The response of soil organic matter (OM) decomposition to increasing temperature is a critical aspect ecosystem responses global change. impacts climate warming on dynamics have not been resolved due apparently contradictory results from field and lab experiments, most which has focused labile carbon with short turnover times. But the majority total stocks are comprised times decades centuries. Understanding these pools change essential for forecasting longer-term changes in storage. Herein,...
Abstract Respiration, which is the second most important carbon flux in ecosystems following gross primary productivity, typically represented biogeochemical models by simple temperature dependence equations. These equations were established 19th century and have been modified very little since then. Recent applications of these to data on soil respiration produced highly variable apparent sensitivities. This paper searches for reasons this variability, ranging from biochemical reactions...
I nve s ti ga tors from many diverse disciplines-agron o- m i t , a tm o ph eric ch em eco l
The incidence and importance of fire in the Amazon have increased substantially during past decade, but effects this disturbance force are still poorly understood. forest dynamics two regions eastern were studied. Accidental fires affected nearly 50 percent remaining forests caused more deforestation than has intentional clearing recent years. Forest create positive feedbacks future susceptibility, fuel loading, intensity. Unless current land use practices changed, potential to transform...
Significance Climate change alone is unlikely to drive severe tropical forest degradation in the next few decades, but an alternative process associated with weather and fires already operating southeastern Amazonia. Recent droughts caused greatly elevated fire-induced tree mortality a fire experiment widespread regional that burned 5–12% of Amazon forests. These results suggest feedbacks between extreme climatic conditions could increase likelihood “dieback” near-term. To secure integrity...
SUMMARY The isotope dilution method for measuring gross rates of N mineralization, immobilization, and nitrification was applied to intact soil cores so that the effects mixing were avoided. Soil injected with solutions either 15 NH 4 + or NO − ; mineralization calculated from decline in “N enrichment NH: pool during a 24‐h incubation; 3 pool; consumption disappearance label. assumptions required application this are evaluated. Sensitivity analysis revealed homogeneous added ambient pools...