Carleton Bern, PhD
Carl is a Research Soil Scientist with the USGS Colorado Water Science Center.
My research examines the geochemical interactions between water, rock, and soil in both natural and human-managed systems. I specialize in using isotopes and geochemical tracers to answer questions of both basic and applied research. Areas of focus in my recent work include:
- Using tritium to trace the ages of surface waters and water availability in the Upper Colorado River Basin as part of the USGS Next Generation Water Observing System (NGWOS)
- Salinity in surface waters and soils of the semiarid western U.S.
- Contaminants of concern like PFAS and selenium
- Water and soil effects from uranium mining
Professional Experience
2016-present Research Soil Scientist, USGS Colorado Water Science Center
2010-2016 Research Soil Scientist, USGS Crustal Geophysics and Geochemistry Science Center
2008-2010 Mendenhall Fellow, USGS Crustal Geophysics and Geochemistry Science Center
2006-2008 Post-doctoral researcher, University of California, Santa Barbara
Education and Certifications
Ph.D. University of Colorado, Boulder, Colorado, Ecology and Biogeochemistry
B.S. Virginia Tech, Blacksburg, Virginia, Biology
Science and Products
Colloid mobilization and seasonal variability in a semiarid headwater stream
Iron isotope systematics of shale-derived soils as potentially influenced by small mineral particle loss
Modifications to EPA Method 3060A to Improve Extraction of Cr(VI) from Chromium Ore Processing Residue-Contaminated Soils
Rare earth mineral potential in the southeastern U.S. Coastal Plain from integrated geophysical, geochemical, and geological approaches
The Niobrara Formation as a challenge to water quality in the Arkansas River, Colorado, USA
The distribution and composition of REE-bearing minerals in placers of the Atlantic and Gulf coastal plains, USA
Rare earth element (REE) resources are currently of great interest because of their importance as raw materials for high-technology manufacturing. The REE-phosphates monazite (light REE enriched) and xenotime (heavy REE enriched) resist weathering and can accumulate in placer deposits as part of the heavy mineral assemblage. The Atlantic and Gulf coastal plains of the southeastern United States ar
Soil disturbance as a driver of increased stream salinity in a semiarid watershed undergoing energy development
Quantification of colloidal and aqueous element transfer in soils: The dual-phase mass balance model
A model for assessing, quantifying, and correcting for index element mobility in weathering studies
Tracking solutes and water from subsurface drip irrigation application of coalbed methane-produced waters, Powder River Basin, Wyoming
Unexpected dominance of parent-material strontium in a tropical forest on highly weathered soils
Science and Products
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Filter Total Items: 23
Colloid mobilization and seasonal variability in a semiarid headwater stream
Colloids can be important vectors for the transport of contaminants in the environment, but little is known about colloid mobilization at the watershed scale. We present colloid concentration, composition, and flux data over a large range of hydrologic conditions from a small watershed (Gordon Gulch) in the foothills of the Colorado Front Range. Colloids, consisting predominantly of Si, Fe, and AlAuthorsTaylor J. Mills, Suzanne P. Ancerson, Carleton R. Bern, Arnulfo Aguirre, Louis A. DerryIron isotope systematics of shale-derived soils as potentially influenced by small mineral particle loss
Loss of small mineral particles from soil has been suggested as a process that can produce net isotopic fractionation in the remaining soil. We extracted water dispersible colloids (WDCs) from bulk soil collected at the Susquehanna/Shale Hills Critical Zone Observatory (SSHO) and measured their Fe isotopic composition for comparison to published data from the site. The goal was to explain soil δ56AuthorsCarleton R. Bern, Tiffany Yesavage, Michael PribilModifications to EPA Method 3060A to Improve Extraction of Cr(VI) from Chromium Ore Processing Residue-Contaminated Soils
It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from chromium ore processing residue (COPR). We modified various parameters of EPA 3060A toward understanding the transformation of COPR minerals in the alkaline extraction and improving extraction of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil. Aluminum and Si were the major elements dissolved from NIST 27AuthorsChristopher T. Mills, Carleton R. Bern, Ruth E. Wolf, Andrea L. Foster, Jean Morrison, William BenzelRare earth mineral potential in the southeastern U.S. Coastal Plain from integrated geophysical, geochemical, and geological approaches
We combined geophysical, geochemical, mineralogical, and geological data to evaluate the regional presence of rare earth element (REE)−bearing minerals in heavy mineral sand deposits of the southeastern U.S. Coastal Plain. We also analyzed regional differences in these data to determine probable sedimentary provenance. Analyses of heavy mineral separates covering the region show strong correlationAuthorsAnjana K. Shah, Carleton R. Bern, Bradley S. Van Gosen, David L. Daniels, William Benzel, James R. Budahn, Karl J. Ellefsen, Adam T. Karst, Richard DavisThe Niobrara Formation as a challenge to water quality in the Arkansas River, Colorado, USA
Study regionArkansas River, east of the Rocky Mountains.Study focusCretaceous sedimentary rocks in the western United States generally pose challenges to water quality, often through mobilization of salts and trace metals by irrigation. However, in the Arkansas River Basin of Colorado, patchy exposure of multiple Cretaceous formations has made it difficult to identify which formations are most proAuthorsCarleton R. Bern, Robert W. Stogner, Sr.The distribution and composition of REE-bearing minerals in placers of the Atlantic and Gulf coastal plains, USA
Rare earth element (REE) resources are currently of great interest because of their importance as raw materials for high-technology manufacturing. The REE-phosphates monazite (light REE enriched) and xenotime (heavy REE enriched) resist weathering and can accumulate in placer deposits as part of the heavy mineral assemblage. The Atlantic and Gulf coastal plains of the southeastern United States ar
AuthorsCarleton R. Bern, Anjana K. Shah, William Benzel, Heather A. LowersSoil disturbance as a driver of increased stream salinity in a semiarid watershed undergoing energy development
Salinization is a global threat to the quality of streams and rivers, but it can have many causes. Oil and gas development were investigated as one of several potential causes of changes in the salinity of Muddy Creek, which drains 2470 km2 of mostly public land in Wyoming, U.S.A. Stream discharge and salinity vary with seasonal snowmelt and define a primary salinity-discharge relationship. SaliniAuthorsCarleton R. Bern, Melanie L. Clark, Travis S. Schmidt, JoAnn M. Holloway, Robert McdougalQuantification of colloidal and aqueous element transfer in soils: The dual-phase mass balance model
Mass balance models have become standard tools for characterizing element gains and losses and volumetric change during weathering and soil development. However, they rely on the assumption of complete immobility for an index element such as Ti or Zr. Here we describe a dual-phase mass balance model that eliminates the need for an assumption of immobility and in the process quantifies the contribuAuthorsCarleton R. Bern, Aaron Thompson, Oliver A. ChadwickA model for assessing, quantifying, and correcting for index element mobility in weathering studies
Evidence shows that high field strength (HFS) elements commonly used to index chemical weathering are variably mobile. This mobility may be linked to redistribution of suspended solids. A mass-balance model is presented that can quantify such redistribution without assuming immobility for any single element. Two tropical weathering profiles on quartz diorite and basalt are examined and redistributAuthorsCarleton R. Bern, Arthur F. WhiteTracking solutes and water from subsurface drip irrigation application of coalbed methane-produced waters, Powder River Basin, Wyoming
One method to beneficially use water produced from coalbed methane (CBM) extraction is subsurface drip irrigation (SDI) of croplands. In SDI systems, treated CBM water (injectate) is supplied to the soil at depth, with the purpose of preventing the buildup of detrimental salts near the surface. The technology is expanding within the Powder River Basin, but little research has been published on itsAuthorsMark A. Engle, Carleton R. Bern, Richard W. Healy, J.I. Sams, J.W. Zupancic, K.T. SchroederUnexpected dominance of parent-material strontium in a tropical forest on highly weathered soils
Controls over nutrient supply are key to understanding the structure and functioning of terrestrial ecosystems. Conceptual models once held that in situ mineral weathering was the primary long-term control over the availability of many plant nutrients, including the base cations calcium (Ca), magnesium (Mg), and potassium (K). Recent evidence has shown that atmospheric sources of these “rock-derivAuthorsCarleton R. Bern, Alan R. Townsend, G. Lang Farmer