Carleton Bern, PhD
Biography
I am a Research Soil Scientist with the U.S. Geological Survey in the 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:
(1) Salinity in surface waters and soils of the semiarid western U.S.
(2) Water quality in relation to uranium mining
(3) Improving the 100-year-old methodology for quantifying soil geochemical development
(4) Applying stable isotopes of water to understanding water availability in the Headwaters of the Colorado and Gunnison River Basin as part of the USGS Next Generation Water Observing System (NGWOS)
Science and Products
Technique Used to Distinguish Natural Background from Human-Caused Enrichment of Trace Elements in Soils
Human activities can enrich toxic trace elements like uranium and arsenic in the environment, but these elements also are from natural sources and occur at background levels. Scientists utilized a technique that identifies the background and the elemental fingerprint of human-caused enrichment and tested the new technique on data collected near uranium mines in Arizona.
Brine Research Instrumentation and Experimental (BRInE) Lab
In the “Brine Research Instrumentation and Experimental (BRInE) Lab” task of the Oil and Gas Waters Project we produce and report water quality data in support of studies internal and external to the project. Conduct laboratory research to complement and provide tools to help answer basic questions...
Soil Disturbance Can Increase Stream Salinity in Semiarid Watersheds
Soil disturbance from construction of roads, pipelines, and well pads on naturally salt-rich soils was determined to be a potential factor resulting in increased salinity in a southern Wyoming stream. Construction can expose salt-rich soils in the subsurface to increased contact with rain and snow, thus mobilizing salts through runoff or water percolating into soils.
Salt flushing, salt storage, and controls on selenium: A 31-year mass-balance analysis of an irrigated, semiarid valley
Salinity, selenium, and uranium pose water‐quality challenges for the Arkansas River in southeastern Colorado and other rivers that support irrigation in semiarid regions. This study used 31 years of continuous discharge and specific conductance (SC) monitoring data to assess interannual patterns in water quality using mass balance on a 120‐...
Bern, Carleton R.; Holmberg, Michael; Kisfalusi, Zachary Effects of John Martin Reservoir on water quality and quantity: Assessment by chemical, isotopic, and mass-balance methods
Water quality and quantity can be influenced by transit through and storage in reservoirs. Assessing such effects can be challenging, however, because of mixing and residence times, and inter-annual net storage and release from both the reservoir itself and surrounding porosity. Here, different methodologies were used to assess the effect of John...
Bern, Carleton R.; Holmberg, Michael; Kisfalusi, Zachary Comment on “Particle fluxes in groundwater change subsurface rock chemistry over geologic time”
Over the last decade, studies at the Shale Hills Critical Zone Observatory (Shale Hills) have greatly expanded knowledge of weathering in previously understudied, shale-mantled terrains, as well as Earth's Critical Zone as a whole. Among the many discoveries made was the importance of redistribution and losses of micron-sized...
Bern, Carleton R.; Tiffany Yesavage Improved enrichment factor calculations through principal component analysis: Examples from soils near breccia pipe uranium mines, Arizona, USA
The enrichment factor (EF) is a widely used metric for determining how much the presence of an element in a sampling media has increased relative to average natural abundance because of human activity. Calculation of an EF requires the selection of both a background composition and a reference element, choices that can strongly influence the...
Bern, Carleton R.; Walton-Day, Katie; Naftz, David L. Dual-phase mass balance modeling of small mineral particle losses from sedimentary rock-derived soils
Losses of small mineral particles can be a significant physical process that affects the elemental composition of soils derived from sedimentary rocks. Shales, in particular, contain abundant clay-sized minerals that can be mobilized by simple disaggregation, and solutional weathering is limited because the parent rock is composed primarily...
Bern, Carleton R.; Yesavage, Tiffany 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....
Mills, Taylor J.; Suzanne P. Ancerson; Bern, Carleton R.; Aguirre, Arnulfo; Derry, Louis A. Iron 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...
Bern, Carleton R.; Yesavage, Tiffany; Pribil, Michael Modifications 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...
Mills, Christopher T.; Bern, Carleton R.; Wolf, Ruth E.; Foster, Andrea L.; Morrison, Jean M.; Benzel, William M. Rare 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...
Shah, Anjana K.; Bern, Carleton R.; Van Gosen, Bradley S.; Daniels, David L.; Benzel, William M.; Budahn, James R.; Ellefsen, Karl J.; Karst, Adam; Davis, Richard The 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...
Bern, Carleton R.; Stogner, Sr., Robert W. 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...
Bern, Carleton R.; Shah, Anjana K.; Benzel, William M.; Lowers, Heather A. Soil 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...
Bern, Carleton R.; Clark, Melanie L.; Schmidt, Travis S.; Holloway, JoAnn M.; Mcdougal, Robert