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Carol Kendall

Isotope Tracers of Biogeochemical and Hydrologic Processes
The purpose of my research group is to develop new methods and applications of environmental isotopes to solve problems of national importance. In specific, the overall goal is to use environmental isotopes, combined with other biogeochemical measurements and hydrologic and biogeochemical modeling, to increase our understanding of biogeochemical and hydrological processes, nutrient and organic matter sources, subsurface flowpaths, and water age distributions in diverse environments. Many of our studies piggyback on the sampling efforts of major monitoring programs to investigate causes of hypoxia and food web problems. Our work provides critical scientific support for these monitoring programs. A long-term career...
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This data set consists of chemical and stable isotope data obtained through the analysis of discrete water samples collected from 14 fixed sampling locations in the northern Sacramento-San Joaquin Delta at roughly monthly intervals between April 2011 and November 2012.
Riverine particulate organic matter (POM) samples were collected bi-weekly to monthly from 40 sites in the Mississippi, Colorado, Rio Grande, and Columbia River Basins (USA) in 1996–97 and analysed for carbon and nitrogen stable isotopic compositions. These isotopic compositions and C : N ratios were used to identify four endmember sources of POM: plankton, fresh terrestrial plant material, aquatic plants, and soil organic material. This large-scale study also incorporated ancillary chemical and hydrologic data to refine and extend the interpretations of POM sources beyond the source characterizations that could be done solely with isotopic and elemental ratios. The ancillary data were especially useful for differentiating...
In the Rocky Mountains, there is uncertainty about the source areas and emission types that contribute to nitrate (NO3) deposition, which can adversely affect sensitive aquatic habitats of high-elevation watersheds. Regional patterns in NO3 deposition sources were evaluated using NO3 isotopes in five National Parks, including 37 lakes and 7 precipitation sites. Results indicate that lake NO3 ranged from detection limit to 38 μeq/L, δ18O (NO3) ranged from −5.7 to +21.3‰, and δ15N (NO3) ranged from −6.6 to +4.6‰. δ18O (NO3) in precipitation ranged from +71 to +78‰. δ15N (NO3) in precipitation and lakes overlap; however, δ15N (NO3) in precipitation is more depleted than δ15N (NO3) in lakes,...
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Data was collected in the Cache Slough Complex located in the northern San Francisco Estuary to characterize water quality parameters at high spatial resolution. Data collection was conducted on three separate occasions: October 2017, May 2018, and October 2018. Data set includes nitrate, ammonium, ortho-phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, chlorophyll, stable isotopes including water isotopes. Measurements were used to calculate evaporation to inflow ratios and water residence time.
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