Soils

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...

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...

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...

Stream transport (lateral transfer) of carbon remains a poorly understood flux within the global carbon budget. This research addresses the need to refine our knowledge of both provenance and transformations of Dissolved Organic Matter (DOM) as it moves from mountains to sea. Interpreting shifts in carbon quality with increasing stream order, and how these patterns change with variation in...

The ecological foundation of thousands of acres of wetland habitat is being impacted by changes in land cover, land use, climate, and invasive species. This project utilizes USGS remotely-sensed products, along with experimental and observational field data to develop spatially-explicit, landscape-scale models of invasive cattails and soil biogeochemical processes. These models will assist...

Improper land use during drought has been a major driver of land degradation in drylands globally, especially in the western U.S. Increasing aridity in western U.S. drylands under future climates will exacerbate risks associated with drought and land use decisions. This project provides critical observational, experimental, and modelling evidence to support our DOI partners with decision processes...

Changing temperature, precipitation, and land use intensification has resulted in global soil degradation. The accompanying loss of soil organic matter (SOM) decreases important soil health services. Soil organic matter is a major global pool of carbon; if SOM can be increased, soils can mitigate elevated atmospheric CO2. However, there are major knowledge gaps in SOM persistence. This project...

This project studies past high sea levels on coastlines that preserve fossil coral reefs or marine terraces. We ascertain the magnitudes of sea-level high stands by field mapping, stratigraphic measurements, and precise elevation measurements. Geochronology is accomplished by radiocarbon dating of mollusks (for Holocene-to-last-glacial deposits), uranium-series dating of corals (for high-sea...