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College of Arts & Sciences
School of the Earth, Ocean and Environment


Robert Thunell

Carolina Distinguished Professor
School of the Earth, Ocean and Environment

Phone Number: 803 777-7593
Email: thunell@geol.sc.edu
Website: http://www.seoe.sc.edu/msrl
Office: EWS 514
Research Areas: Biogeochemistry & Geochemistry
Climate Change
Oceanography
Research Summary:

Reconstructing paleoceanographic and paleoclimatic conditions using deep sea sediments; measuring the production and flux of sediments in the ocean; calibration of paleoclimate proxies.

Curriculum vitae: Download PDF
Dr. Bob Thunell

Google Scholar Profile

Education:
A.B., 1973 Brown University;
M.S., 1975, Ph. D., 1978, University of Rhode Island;
Postdoctoral Fellow, 1978-1979, Woods Hole Oceanographic Institution 
 

Research Areas: Reconstructing paleoceanographic and paleoclimatic conditions using deep sea sediments; measuring the production and flux of sediments in the ocean; calibration of paleoclimate proxies.  For laboratory facilities see Marine Sediments Research Lab

Paleoceanographic/ Paleoclimatic Reconstructions: The marine sedimentary record contains perhaps the best long-term archive of global climate change. Using a variety of analytical techniques, including micropaleontology, sediment geochemistry and stable isotope geochemistry, we are trying to reconstruct the paleoceanographic and paleoclimatic conditions that existed in various regions during the Neogene. Our current emphasis is on high resolution (decadal to century-scale) studies of late Pleistocene climate. This type of research is currently being carried out in the Gulf of California, offshore California, the southern Caribbean, the western North Atlantic, and the Indonesian region.

Sediment Production and Fluxes: Through the use of moored sediment traps, we are studying temporal variability in the production and flux of sediments in the ocean. In particular, we are studying seasonal to interannual changes in sediment flux in response to climate forcing and changing upper ocean conditions. Current sediment trapping studies in Santa Barbara Basin and the Gulf of California are designed to study the impact of ENSO on sedimentation in these regions. A third trapping program in Cariaco Basin is examining carbon fluxes in a coastal upwelling regime. Additionally, in all three of these regions sediment laminae are preserved on the sea floor due to anoxic bottom conditions and our sediment trap work is allowing us to model varve formation in these basins.

Climate Proxy Development and Calibration: Reconstructing the history of the oceans is dependent on our ability to reliably extract from the sediment record information on physical, chemical and biological processes. Our sediment trapping work is contributing to the development and calibration of various climate proxies. For example, we are studying the oxygen isotopic composition of multiple species of planktonic foraminifera in order to use this as a tool for reconstructing upper ocean thermal structure in the past.


Recent Publications:

Tems, C., Berelson, W., Thunell, R., Tappa, E., Xiaomei, X., Khider, D., Lund, S., and Gonzalrz-Yajimovich, O., 2016. Sedimentary δ15N reveal decadal frequency fluctuations in the eastern tropical north Pacific oxygen minimum zone during the last 1200 years, Paleoceanography 31, doi:10.1002/2015PA002904.

Raven, M., Sessions, A., Adkins, J., and Thunell, R., 2016. Rapid organic matter sulfurization in sinking particles from the Cariaco Basin water column, Geochimica Cosmochimica Acta 190, 175-190

Gibson, K., Thunell, R., Machain-Castillo, M., Fehrenbacher, J, Spero, H., Wejnert, K, Nava-Fernandez, X., and Tappa, E., 2016. Evaluating controls on planktonic foraminiferal geochemistry in the Eastern Tropical North Pacific, Earth and Planetary Science Letters 452, 90-103.

Osborne, E., Thunell, R., Marshall, B., Holm, J., Tappa, E., Benitez-Nelson, C., Cai, W., and Chen, B., 2016. Calcification of the planktonic foraminifera Globigerina bulloides and carbonate ion concentration: Results from the Santa Barbara Basin, Paleoceanography 31, doi.10.1002/2016PA002933.

Gibson, K., Thunell, R., Tappa, E., Peterson, L., and McConnell, M., 2015. The influence of rapid, millennial-scale climate change on nitrogen isotope dynamics of the Cariaco Basin during Marine Isotope Stage 3, Paleoceanography 30, 253-268, DOI: 10.1002/2014PA002684.

Pinckney, J., Benitez-Nelson, C., Thunell, R., Muller-Karger, F., Lorenzoni, L., Troccoli, L., Varela, R., 2015. Phytoplankton community structure and depth distribution changes in the Cariaco Basin between 1996 and 2010. Deep-Sea Research 101. 27-37.

Marshall, B., Thunell, R., Spero, H., Henehan, M., Lorenzoni, L., and Astor, Y., 2015. Morphometric and stable isotope differentiation of Orbulina universa morphotypes from the Cariaco Basin, Venezuela, Marine Micropaleontology 120, 46-64.

Calvert, S., Piper, D., Thunell, R., and Astor, Y., 2015. Elemental settling and burial fluxes in the Cariaco Basin, Marine Chemistry 177, 607-629

Marshall, B., Thunell, R., Henehan, M., Astor, Y., and Wejnert, K., 2013. Planktonic foraminiferal area density as a proxy for carbonate ion concentration: A calibration study using the Cariaco Basin ocean time series, Paleoceanography 28, 363-376, doi: 10.1002/paleo.20034.

Wejnert, K., Thunell, R., and Astor, Y., 2013. Comparison of species-specific oxygen isotope paleotemperature equations: Sensitivity analysis using planktonic foramifera from the Cariaco Basin, Venezuela, Marine Microplaeontology 101, 76-88.

Scranton, M., Taylor, G., Thunell, R., Benitez-Nelson, C., Muller-Karger, F., Fanning, K., Lorenzoni, L., Montes, E., Varella, R. and Astor, Y., 2014. Interannual to subdecadal variability in the nutrient geochemistry of the Cariaco Basin, Oceanography 27, 148-159

Pichevin, L., Ganeshram, R., Gelbert, W., Thunell, R., and Hinton, R., 2014. Silica burial enhanced by iron limitation in oceanic upwelling regions, Nature Geoscience 7, 541-546.

Deutsch, C., Berelson, W., Thunell, R., and others, 2014. Centennial changes in North Pacific anoxia linked to tropical trade winds, Science 345, 665-668.

Montes, E., Altabet, M., Muller-Karger, F., Scranton, M., Thunell., R., Benitez-Nelson, C., Lorenzoni, L., and Astor, Y., 2013. Biogenic nitrogen gas production at the oxic-anoxic interface in the Cariaco Basin, Vemezuela, Biogeosciences 10, 267-269

Krause, J., Brzezinski, M., Siegel, D., and Thunell, R., 2013. Biogenic silica standing stock and export in the Santa Barbara Channel ecosystem, Journal of Geophysical Research: Oceans 118, 736-749.

Turich, C., Schouten, H., Thunell, R., Varela, R., Astor, Y. and Wakeham, S., 2013. Comparison of TEX86 and temperature proxies in sinking particles in the Cariaco Basin, Deep-Sea Research 78, 115-133.

Montes, E., Thunell, R., Muller-Karger, F., Tappa, E., Lorenzoni, L., Troccoli, L., Astor, Y. and Varela, R., 2013. Sources of δ15N variability in sinking particulate nitrogen in the Cariaco Basin, Venezuela, Deep Sea Research II, 93, 96-107..

Astor, Y., Lorenzoni, L., Thunell, R., Varela, R., Muller-Karger, F., Troccoli, L., Taylor, G., Scranton, M., Tappa, E., and Rueda, D., 2013 Interannual variability in sea surface temperature and fCO2 changes in the Cariaco Basin, Deep Sea Research II, 93, 33-43.

Wurtzel, J., Black, D., Thunell, R., Peterson, L., Tappa, E., and Rahman, S., 2013. Mechanisms of southern Caribbean SST variability over the last two millennia, Geophysical research Letters 40, 1-5, doi:10.1002/2013GL058458.

Marshall, B., Thunell, R., Henehan, M., Astor, Y., and Wejnert, K., 2013. Planktonic foraminiferal area density as a proxy for carbonate ion concentration: A calibration study using the Cariaco Basin ocean time series, Paleoceanography 28, 363-376, doi: 10.1002/paleo.20034.

Wejnert, K., Thunell, R., and Astor, Y., 2013. Comparison of species-specific oxygen isotope paleotemperature equations: Sensitivity analysis using planktonic foramifera from the Cariaco Basin, Venezuela, Marine Microplaeontology 101, 76-88.

Scranton, M., Taylor, G., Thunell, R., Benitez-Nelson, C., Muller-Karger, F., Fanning, K., Lorenzoni, L., Montes, E., Varella, R. and Astor, Y., 2014. Interannual to subdecadal variability in the nutrient geochemistry of the Cariaco Basin, Oceanography 27, 148-159

Montes, E., Muller-Karger, F., Thunell, R. and others, 2012. Vertical fluxes of particulate biogenic material through the euphotic and twilight zones in the Cariaco Basin, Venezuela, Deep Sea Research 67, 73-84

Hertzberg, J., Black, D., Peterson, L., Thunell, R., and Haug, G., 2012. Decadal- to centennial-scale tropical Atlantic climate variability across a Dansgaard-Oeschger cycle, Paleoceanography 27, PA3218, doi:10.1029/2011PA002251.

Ren, H., Sigman, D., Thunell, R and Prokopenko, M., 2012. Nitrogen isotopic composition of planktonic foraminifera from the modern ocean and recent sediments, Limnology and Oceanography 57, 1011-1024.

Cronin, T., Rayburn, J., Guilbault, J., Thunell, R. and Franzi, D., 2012. Stable isotope evidence for glacial lake drainage through the St. Lawrence Estuary, eastern Canada, ~ 13.1-12.9 ka, Quaternary International 260, 55-65.

Pichevin, L., Ganeshram, R., Reynolds, B., Prahl, F., Pedersen, T., Thunell, R., and McClymont, E., 2012. Silicic acid biogeochemistry in the Gulf of California: Insights from sedimentary Si isotopes. Paleoceanography 27, PA2201, doi: 10.1029/2011PA002237..

McClymont, E., R. Ganeshram, L. Pichevin, H. Talbot, B. van Dongen, R. Thunell, A. Haywood, J. Singarayer and P. Valdes, 2012. Sea-surface temperature records of Termination 1 in the Gulf of California: challenges for seasonal and inter-annual analogues of tropical Pacific climate change, Paleoceanpgraphy 27, PA2202, doi:10.1029/2011PA002226.