Biogeochemistry, hydrology, and geomorphology.
The earth-surface environment and how it changes on human and geologic time scales. My emphasis is on climate and land-use changes and how these affect processes that control the composition and dispersal of dissolved and solid phases in rivers and trace gases in the atmosphere. My work combines both field and theoretical studies using the tools of geology, biology, biogeochemistry, and geography.
Current areas of investigation: (1) Can we develop general physically and biologically based models of the processes that generate the dissolved and particulate load in rivers and trace substances in the atmosphere? (2) How do various phases chemically partition during transport in rivers and estuaries? (3) What are the dispersal pathways of river-borne substances through rivers and estuaries into the coastal environment? (4) How do human activities, particularly land-use change, affect environments being examined? (5) How do we use rivers to integrate phenomena at local spatial scales up to continental scales? (6) Can we formulate provenance models to reconstruct past geologic environments?
- Meritorious Service Award for "exceptional contributions to the development of new and innovative research programs in the U.S. Geological Survey.", Department of the Interior, 2002