Breadcrumb
Bio
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?
Education
- PhD: Massachusetts Institute of Technology - Woods Hole Oceanographic Institute, 1980
Awards
- 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
Research
Research interests: biogeochemistry, hydrology, and geomorphology.
Publications
Recent publications
PETROLOGY OF FLUVIAL SANDS FROM THE AMAZONIAN FORELAND BASIN, PERU AND BOLIVIA - DISCUSSION
Publication Date: 1990-12-01
Type: Journal Article
PHYSIOGRAPHIC CONTROLS ON THE COMPOSITION OF SEDIMENTS DERIVED FROM VOLCANIC AND SEDIMENTARY TERRAINS ON BARRO-COLORADO ISLAND, PANAMA - REPLY
Publication Date: 1990-09-01
Type: Journal Article
THE CHEMICAL BEHAVIOR OF TRACE-METALS AND RA-226 DURING ESTUARINE MIXING IN THE MULLICA RIVER ESTUARY, NEW-JERSEY, USA - A COMPARISON BETWEEN FIELD OBSERVATION AND EQUILIBRIUM CALCULATION
Publication Date: 1990-07-30
Type: Journal Article
THE LOW-SALINITY PHYSICOCHEMICAL BEHAVIOR OF METAL-BEARING COLLOIDS DURING BATCH-MIXING EXPERIMENTS
Publication Date: 1990-04-22
Type: Journal Article
GERMANIUM AND SILICON IN RIVERS OF THE ORINOCO DRAINAGE-BASIN
Publication Date: 1990-04-19
Type: Journal Article
CONSUMPTION OF ATMOSPHERIC METHANE IN SOILS OF CENTRAL PANAMA: EFFECTS OF AGRICULTURAL DEVELOPMENT
Publication Date: 1990-03-01
Type: Journal Article
METAL AND NUTRIENT BEHAVIOR IN THE RARITAN ESTUARY, NEW-JERSEY, USA - THE EFFECT OF MULTIPLE FRESH-WATER AND INDUSTRIAL-WASTE INPUTS
Publication Date: 1990-01-25
Type: Journal Article
Weathering processes and the composition of inorganic material transported through the Orinoco River system, Venezuela and Colombia
Type: Chapter
GERMANIUM GEOCHEMISTRY IN THE SOUTHERN-CALIFORNIA BORDERLANDS
Publication Date: 1989-11-01
Type: Journal Article
PHYSIOGRAPHIC CONTROLS ON THE COMPOSITION OF SEDIMENTS DERIVED FROM VOLCANIC AND SEDIMENTARY TERRAINS ON BARRO COLORADO ISLAND, PANAMA
Publication Date: 1989-09-01
Type: Journal Article
GERMANIUM/SILICON FRACTIONATION DURING BIOGENIC OPAL FORMATION
Publication Date: 1988-08-01
Type: Journal Article
SEDIMENT SAMPLING THROUGH ULTRAFILTRATION
Publication Date: 1988-07-01
Type: Journal Article
1ST-CYCLE QUARTZ ARENITES IN THE ORINOCO RIVER BASIN, VENEZUELA AND COLOMBIA
Publication Date: 1988-05-01
Type: Journal Article
Weathering and Erosion in the Humid Tropics
Type: Chapter
CROSS-CHANNEL MIXING AND ITS EFFECT ON SEDIMENTATION IN THE ORINOCO RIVER
Publication Date: 1987-10-01
Type: Journal Article
GEOCHEMISTRY OF THE AMAZON .3. WEATHERING CHEMISTRY AND LIMITS TO DISSOLVED INPUTS
Publication Date: 1987-07-15
Type: Journal Article
MAJOR ELEMENT COMPOSITIONAL VARIATION WITHIN AND BETWEEN DIFFERENT LATE EOCENE MICROTEKTITE STREWNFIELDS
Publication Date: 1987-03-31
Type: Journal Article
ANOXIC EVENTS, PRODUCTIVITY RHYTHMS, AND THE ORBITAL SIGNATURE IN A MID-CRETACEOUS DEEP-SEA SEQUENCE FROM CENTRAL ITALY
Publication Date: 1986-12-01
Type: Journal Article
DISSOLUTION AT DISLOCATION ETCH PITS IN QUARTZ
Publication Date: 1986-10-01
Type: Journal Article
DISLOCATION ETCH PITS IN QUARTZ
Publication Date: 1986-01-01
Type: Journal Article
DISTRIBUTION AND FLUX OF RA-226 AND RA-228 IN THE AMAZON RIVER ESTUARY
Publication Date: 1985-01-01
Type: Journal Article
River Chemistry, Geology, Geomorphology, and Soils in the Amazon and Orinoco Basins
Type: Chapter
CHEMICAL CONTROLS ON ETCH PIT FORMATION AT DISLOCATION OUTCROPS IN QUARTZ
Publication Date: 1985-01-01
Type: Journal Article
The effects of provenance and diagenesis on clay content and crystallinity in Miocene through Pleistocene deposits, southwestern Taiwan
Type: Journal Article
HYDROTHERMAL MN-DEPOSITS OF THE FRANCISCAN ASSEMBLAGE .2. ISOTOPE AND TRACE-ELEMENT GEOCHEMISTRY, AND IMPLICATIONS FOR HYDROTHERMAL CONVECTION AT SPREADING CENTERS
Publication Date: 1984-01-01
Type: Journal Article
Pages
Outreach
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