MARINE BIOGEOCHEM LAB
University of South Carolina -Columbia
CURRENT PROJECTS
Particle Flux: Elucidating spatial and temporal variability in particle export using shortlived radionuclides, 238U:234Th, as part of the GEOTRACES Program.
Sediment Traps
Examining particle flux and composition in the Santa Barbara Basin in response to physical mixing and biogeochemistry
Blackwater Ecosystems: Defining blackwater systems by determining the sources and composition of organic matter using optical properties
ABOUT ME
I am a Carolina Distinguished Professor & Endowed Chair in Marine Studies in the McCausland College of Arts & Sciences at the University of South Carolina. My research focuses on nutrient, carbon, and contaminant biogeochemistry, sinking particle fluxes, and the application of naturally occurring radionuclides to understand freshwater, coastal, and open-ocean processes. Over the past two decades, I have authored or co-authored more than 150 peer-reviewed articles, including lead-author publications in Science and Nature, and have been continuously supported by substantial, multi-year research and education grants from the National Science Foundation and the National Aeronautics and Space Administration, among others. My research honors include the Early Career Award in Oceanography from AGU and Fulbright and Marie Curie Fellowships. I am a AAAS, ASLO , and Oceanography Fellow. I love to teach and mentor students and have received the University of South Carolina’s Distinguished Professor of the Year Award, the SC SEC Faculty Achievement Award, and received USC's Outstanding Faculty Advisor of the Year. I was honored to receive the Sulzman Award for Excellence in Education and Mentoring from the Biogeosciences Section of AGU, the Oceanography Society's Mentoring Award for Excellence and Innovation in Mentoring the Next Generation of Ocean Scientists, and the Outstanding Educator Award from the Association for Women Geoscientists. I am regularly called upon by national and international scientific and policy agencies and currently serve as the Chair of the NAS Ocean Studies Board, the White House Ocean Research Advisory Panel, and as a member of Sciencemoms, a group founded to help moms concerned about climate change who are seeking more knowledge and how they can help. I earned B.S. degrees in chemistry and oceanography from the University of Washington and a Ph.D. in oceanography from the Woods Hole Oceanographic Institute/Massachusetts Institute of Technology Joint Program in 1999.
RESEARCH
My research examines the mechanisms of aquatic particle formation, export, and burial and how the composition of these particles changes both temporally and spatially. Much of this work focuses specifically on phosphorus and carbon biogeochemistry, but includes other elements and compounds ranging from mercury to the neurotoxin, domoic acid. We use a variety of geochemical techniques in our laboratory, including radiochemistry and mass spectrometry. My research sites span the globe, from coastal South Carolina and California to South Africa.
PUBLICATIONS
SELECTED
Index Web of Science: 49, Google Scholar:59, https://orcid.org/0000-0002-1004-5048; https://scholar.google.com/citat
H-Index Web of Science: 49, Google Scholar:59, https://orcid.org/0000-0002-1004-5048; https://scholar.google.com/citations?user=nEuGaD4AAAAJ&hl=en
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* Denotes my graduate student or my postdoc as author, **Denotes my undergraduate student as author
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Havard, E., Cherry, K, Benitez-Nelson, CR, Tappa, E, Davis, CV (2025) Decreasing foraminiferal flux in response to ongoing climate change in the Santa Barbara Basin, California, Biogeosciences, 22, 4035–4060, https://bg.copernicus.org/articles/22/4035/2025/.
*Hopper, G, Smith, E, Dormoy-Boulanger, J. Benitez-Nelson, CR (2025) Urbanization impacts dissolved organic matter concentration and quality in a Southeastern United States watershed. Environmental Science & Technology-Water, 5, 1281-1296. https://pubs.acs.org/doi/full/10.1021/acsestwater.4c01054.
*Umhau, B, Motta, LC, Blum, Close, HG, Drazen, JC, Popp, BN, Benitez-Nelson, CR, (2024) Particulate Mercury Export in the Central Pacific Ocean Using 234Th-238U Disequilibria, Marine Chemistry, 265-266, 104433. https://doi.org/10.1016/j.marchem.2024.104433.
Moore, WS, Benitez-Nelson, CR, Schutte, C, Moody, A, Shiller, A, Sibert, RJ, Joye, SJ (2024) SGD-OD: Investigating the Potential Oxygen Demand of Submarine Groundwater Discharge in Coastal Systems, Scientific Reports 14, 9249 (2024). https://doi.org/10.1038/s41598-024-59229-7
*Szewczyk, CJ, Smith, E, Benitez-Nelson, CR (2023) Temperature sensitivity of oxygen demand varies as a function of organic matter source, Frontiers in Marine Science, 10 https://doi.org/10.3389/fmars.2023.1133336.
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Benitez-Nelson, CR, McNeal, KS, Jones, WJ (2023) Improving Retention of Underrepresented Groups in the Geosciences through an Intensive First-Year Experience at the University of South Carolina Oceanography Magazine, 36(4), https://doi.org/10.5670/oceanog.2024.108.
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Motta, LC, Blum, JD, Popp, BN, Umhau, BP, Benitez-Nelson, CR, Close, HG, Washburn, SJ, Drazen, HC (2022). Mercury Isotopic Evidence for the Importance of Particles as a Source of Mercury to Marine Organisms, PNAS, 19 (44) e2208183119, https://doi.org/10.1073/pnas.2208183119.
*McCabe, K, Smith, E, Lang, S, Osburn, C, Benitez-Nelson, C (2021) Particulate and dissolved organic matter in storm water runoff influences oxygen demand in urbanized headwater catchments, Environmental Science and Technology, https://doi.org/10.1021/acs.est.0c04502 .
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Buesseler, KO, Benitez-Nelson, CR. Roca-Marti, M, Wyatt, AM, Laure Resplandy, L, Clevenger, SJ, Drysdale, JA., Estapa, ML, Pike, S, Umhau, BP (2020) High resolution spatial and temporal measurements of particulate organic carbon flux using thorium-234 in the NE Pacific Ocean during the EXPORTS Program, Elementa: Science of the Anthropocene, 8 (1): 030. https://doi.org/10.1525/elementa.030
*Sarno, CT, Benitez-Nelson, CR, Ziolkowski, LA, Hendy, IL, *Davis, CV, Tappa, EJ, Thunell, RC (2020) The Impacts of Flood, Drought, and Turbidites on Organic Carbon Burial over the Past 2,000 years in the Santa Barbara Basin, California, Paleoceanography and Paleoclimatology, 35, e2020PA003849. https://doi.org/10.1029/2020PA003849
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*Davis, CV, Benitez-Nelson CR (2020) Evidence for rapid trace element alteration of planktic foraminiferal shells from the Panama Basin: Manganese adsorption during vertical transport. Marine Micropaleontology, 157, 101872 https://doi.org/10.1016/j.marmicro.2020.101872.
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*Bell, DW, Pellechia, P, Ingall, E.D., Benitez-Nelson, CR (2020) Resolving marine dissolved organic phosphorus (DOP) composition in a coastal estuary, North Inlet, South Carolina. Limnology and Oceanography, 65(11), 27872-2799. https://doi.org/10.1002/lno.11552
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OVERVIEW OF COURSES TAUGHT
I take great pride in every course they teach. While the subject matter may vary between classes, each curriculum is designed to ensure students understand the key concepts and gain valuable critical thinking skills that can be applied to other courses and life outside of the classroom.
MSCI 101: INTRODUCTION TO OCEANOGRAPHY
Origin and evolution of the oceans, plate tectonics, ocean circulation, waves and tides, seawater and sediment composition, and influences on biology. Three lecture and three laboratory hours per week. Scheduled field trips required.
Introduction to radioactivity and the use of radionuclides to study environmental processes, including age-dating and biogeochemical cycling in aquatic systems. Two lectures per week.
MSCI 782: CHEMICAL OCEANOGRAPHY
Chemical characteristics of sea water, distribution of properties, and chemical processes in the oceans.
OUTREACH
SCIENCE MOMS
We’re a group of nonpartisan climate scientists and mothers, working to give our children the planet they deserve. Science Moms was founded to help mothers who are concerned about their childrens’ planet, but aren’t confident in their knowledge about climate change or how they can help.