Biogeochemical Cycling

Soils are the foundation of terrestrial ecosystems. They provide critical services including supplying a substrate and the nutrients necessary for plant growth, retaining moisture from precipitation, filtering contaminants from percolating waters, and acting as a sink of carbon. Healthy soils are key to sustaining both human and ecosystem health. However, global- and regional-scale disturbances...

California is experiencing changes in precipitation and wildfire regimes. Longer, hotter fire seasons along with extremes in precipitation are expected to continue. Not only do these disturbances affect the productivity and resilience of ecosystems, they also directly impact human health and wellbeing. Soils hold an immense amount of our terrestrial carbon pool, and the microorganisms and minerals...

This project focuses on development of new interdisciplinary modeling capabilities of long-term time series that capture interactions among climate, land use, water use, and water availability. Research builds on expanding the USGS Forecasting Scenarios of Land Use (FORE-SCE) model and integrating with spatially explicit models from other disciplines. Interdisciplinary models will be co-developed...

Warming and thawing of permafrost soils in the Arctic is expected to become widespread over the coming decades. Permafrost thaw changes ecosystem structure and function, affects resource availability for wildlife and society, and decreases ground stability which affects human infrastructure. Since permafrost soils contain about half of the global soil carbon (C) pool, the magnitude of C losses...

In the intermountain west, seasonal precipitation extremes, combined with population growth, are creating new challenges for the management of water resources, ecosystems, and geologic hazards. This research contributes a comprehensive long-term context for a deeper understanding of past hydrologic variability, including the magnitude and frequency of drought and flood extremes and ecosystem...

Estuaries and their surrounding wetlands are coastal transition zones where freshwater rivers meet tidal seawater. As sea levels rise, tidal forces move saltier water farther upstream, extending into freshwater wetland areas. Human changes to the surrounding landscape may amplify the effects of this tidal extension, impacting the resiliency and function of the upper estuarine wetlands. One visible...

This project integrates soil and ecosystem data to impute important soil properties for hydric soils and wetlands. The work hopes to answer the questions: How have historical changes in biogeochemical processes affected present-day and potential future interactions among land, water, and ecosystem resources? How can improved understanding of historical and present-day biogeochemical interactions...

Wetlands accumulate organic-rich sediment or peat stratigraphically, making them great archives of past environmental change. Wetlands also act as hydrologic buffers on the landscape and are important to global biogeochemical cycling. This project uses wetland archives from a range of environments to better understand how vegetation, hydrology, and hydroclimate has changed on decadal to multi...

While research into eutrophication has been a cornerstone of limnology for more than 100 years, only recently has it become a topic for the remote alpine lakes that are icons of protected national parks and wilderness areas. National park lakes in the western U.S. are threatened by global change, specifically air pollution, warming, and their interactions, and the problem is quickly worsening...

The Southeastern U.S. experiences recurring hydrologic droughts, which can reduce water availability for human consumption and ecosystem services, leading to plant stress and reduced plant growth. This project examines relationships between drought and the water cycle in the Southeast with data from the Panola Mountain Research Watershed (PMRW) near Atlanta, Georgia and other Southeastern sites...

Projections for AD 2100 suggest warming of +1-4°C in the North Pacific Ocean, which will result in widespread transformations throughout the marine environment and western North America. Many of these changes are beyond the predictive capabilities of current climate models. To better address this future uncertainty, our team is developing a geological framework using past warm intervals as...

Land cover and land use (LC/LU), climate, and biogeochemical processing are significant drivers of water quality in streams and rivers over broad scales of space and time. As LC/LU and climate continue to change we can expect changes in water quality. This project seeks to understand the drivers of spatial and temporal variability in water quality across scales using new and existing data to...