Robert C. Thunell

Director, Marine Science Program
Carolina Distinguished Professor
Department of Geological Sciences
Paleoceanography, Paleoclimatology, Deep Sea Sediments

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.

De Bernardi, B., Ziveri, P., Erba, E. And Thunell, R. 2005. Coccolithophore export production during 1997-1998 El Nino event in Santa Barbara Basin, California, Marine Microplaeontology 55, 107-125.

McConnell, M. and Thunell, R., 2005. Calibration of the planktonic foraminiferal Mg/Ca paleothermometer: Sediment traps results from the Guaymas Basin, Gulf of California, Paleoceanography 20, PA2016, doi:10.1029/2004PA001077.

Muller-Karger, F, Varela, R., Thunell, R., Zhang, H., Hu, C. and Walsh, J., 2005. The importance of continental margins in the global carbon cycle, Geophysical Research Letters 32, LO1602, doi:10.1029/2004GL021346.

Smoak, J., Benitez-Nelson, C., Moore, W., Thunell, R., Astor, Y. and Muller Karger, F. 2004. Radionuclide fluxes and particle scavenging in Cariaco Basin, Continental Shelf Research 24, 1451-1463.

Deutsch, C., Sigman, D., Thunell, R., Meckler, A. and Haug, G., 2004. Isotopic constraints on glacial/interglacial changes in the oceanic nitrogen budget, Global Biogeochemical Cycles 18, GB4012, doi:10.1029.

Dean, W., Pride, C., and Thunell, R., 2004. Geochemical cycles in sediments deposited on the slopes of Guaymas and Carmen Basins of the Gulf of California over the last 180 years, Quaternary Science Reviews 23, 1817-1833.

Black, D., Thunell, R., Kaplan, A., Peterson, L. and Tappa, E., 2004. A 2000 year record of Caribbean and tropical North Atlantic hydrographic variability, Paleoceanography 19, PA2022, doi:10.1029.

Woodworth, M., Goni, M., Tappa, E., Tedesco, K., and Thunell, R., 2004. Oceanographic controls on the carbon isotopic composition of sinking particles from the Cariaco Basin. Deep-Sea Research 51, 1955-1974.

Billups, K., Chaisson, W. and Thunell, R., 2004. Mid-Pleistocene fluctuations in subtropical northwestern Atlantic surface ocean stratification. Paleoceanoghy 19, PA2017, doi:10.1029.
Thunell, R., Sigman, D., Muller-Karger, F., Astor, Y. and Varela, R., 2004. The nitrogen isotope dynamics of the Cariaco Basin, Venezuela. Global Biogeochemical Cycles 18, GB3001, doi:10.1029

Stott, L., Cannariato, K., Thunell, R., Haug, G., Koutavas, A., and Lund, S., 2004. Decline of surface temperature and salinity in the western tropical Pacific Ocean in the Holocene epoch, Nature 431, 56-59.

Goni, M., Woodworth, M., Aceves, H., Thunell, R., Tappa, E., Black, D., Muller-Karger, F. and Varela, R., 2004. Generation, Transport and preservation of the alkenone based UK37 sea surface temperature index in the water column and sediments of the Cariaco Basin, Venezuela. Global Biogeochemical Cycles 18, GB2001, doi:10.1029/2003GB002132.

Healey, S. and Thunell, R., 2004. Millennial-scale variability in western subtropical North Atlantic surface and deep water circulation during

Tedesco, K. and Thunell, R., 2003. Seasonal and interannual variations in planktonic foraminiferal flux and assemblage composition in the Cariaco Basin, Venezuela. Journal of Foraminiferal Research 33, 192-210.

Tedesco, K. and Thunell, R., 2003. High resolution tropical climate record for the last 6,000 years. Geophysical Research Letters 30, 17, 1-4.

Friddell, J., Thunell, R., and Guilderson, T. 2003. Increased northeast Pacific climate variability during the warm middle Holocene, Geophysical Research Letters 30, 11, 1-4.

Muller-Karger, F., Varela, R., Thunell, R., Astor, Y., Zhang, H., and Hu, C., 2003. Processes of coastal upwelling and carbon flux in Cariaco Basin, Deep-Sea Research .

Goni, M., Aceves, H., Thunell, R., Tappa, E. and Black, D. 2003. Biogenic fluxes in the Cariaco Basin: A combined study of sinking particulates and underlying sediments, Deep-Sea Research 50, 781-807.

Visser, K., Thunell, R. and Stott, L., 2003. Magnitude and timing of temperature change in the Indo-Pacific warm pool during deglaciation. Nature 421, 152-155.

Friddell, J., Thunell, R. and Heusser, L. 2002. Direct comparison of marine and terrestrial climate variability during marine isotope stages 6 and 5: Results from Santa Barbara Basin ODP Hole 893A, Paleoceanography 17, 1-12.

Bemis, B., Spero, H., and Thunell, R. 2002. Using species-specific paleotemperature equations with foraminifer: a case study in the Southern California Bight, Marine Microplaeontology 46, 405-430.

Thunell, R., Poli, S., and Rio, D. 2002. Changes in deep and intermediate water properties in the western North Atlantic during marine isotope stages 11-12: evidence from ODP leg 172, Marine Geology 189, 63-78.

Stott, L., Poulsen, C., Lund, S. and Thunell, R. 2002. Super ENSO and global climate oscillations at millennial time scales, Science 297, 222-226.

Black, D., Thunell, R., and Tappa, E., 2001, "Planktonic foraminiferal response to the 1997-1998 El Niņo: A sediment-trap record from the Santa Barbara Basin", Geology, vol. 29, no. 12, 1075-1078.

Poli, M.S., Thunell, R., and Rio, D., 2000, "Millenial-scale changes in North Atlantic Deep Water circulation during marine isotope stages 11 and 12: Linkage to Antarctic climate", Geology, vol. 28, no. 9, 807-810.

Thunell, R. and others, 2000, "Organic carbon fluxes, degradation, and accumulation in an anoxic basin: Sediment trap results from Cariaco Basin", Limnology and Oceanography, Vol. 45, No. 2, 300-308.

Emmer, E. and Thunell, R., 2000, "Nitrogen isotope variations in Santa Barbara Basin sediments: Implications for denitrification in th eastern tropical North Pacific during the last 50,000 years", Paleoceanography, Vol. 15, No. 4, 377-387.

Thunell, R. and others, 1999, "Increased marine sediment suspension and fluxes following an earthquake", Nature, Vol. 398, 233-236

Thunell, R., 1998, "Particle fluxes in a coastal upwelling zone: sediment trap results from Santa Barbara Basin, California", Deep-Sea Research, 45, 1863-1884.

Thunell, R., 1998, "Seasonal and annual variability in particle fluxes in the Gulf of California: a response to climate forcing", Deep-Sea Research, 45, 2131-2155.

Thunell, R., 1998, "Continental margin particle flux: seasonal cycles and archives of global change", Oceanus, 40, 15-19.

Patrick, A. and R. Thunell, 1997, "Tropical Pacific sea surface temperatures and upper water column thermal structure during the last glacial maximum", Paleoceanography, 12, 649-657.

Mortyn, P. and R. Thunell, 1997, "Biogenic sedimentation and surface productivity changes in the Southern California Borderlands during the last glacial-interglacial cycle", Marine Geology, 138, 171-192.

Thunell, R. and Q. Miao, 1996, "Sea surface temperature of the western equatorial Pacific Ocean during the Younger Dryas", Quaternary Research, 46, 72-77.

Thunell, R. and others, 1996, "Plankton response to physical forcing in the Gulf of California", Journal of Plankton Research, 18, 2017-2026.

Thunell, R. and P. Mortyn, 1995, "Glacial climate instability in the Northeast Pacific Ocean", Nature, 376, 504-506.

Thunell, R., E. Tappa and D. Anderson, 1995, "Sediment fluxes and varve formation in Santa barbara Basin, offshore California", Geology, 23, 1083-1086.

Thunell, R., D. Anderson, D. Gellar and Q. Miao, 1994, "Sea surface temperature estimates for the tropical western Pacific during the last glaciation and their implications for the Pacific warm pool", Quaternary Research, 41, 255-264.

Bob Thunell
Dept. of Geological Sciences
700 Sumter Street
Univ. of South Carolina
Columbia, SC 29208

Phone: 803 777-7593
FAX: 803 777-4525
Internet: thunell@geol.sc.edu