Dr. David K. Watkins, Professor
Department of Earth & Atmospheric Sciences
University of Nebraska-Lincoln
330 Bessey Hall
Lincoln, Nebraska 68588-0340
My research is based on calcareous nannofossils, the smallest of all skeletal fossils routinely preserved in marine sediments. They are the main component of chalk (above). The rapid evolution of this group and their global distributions make them ideal biostratigraphic indicators for the Late Triassic through Recent. My students and I are currently pursuing projects to examine the variations in the biostratigraphy of both Cretaceous and Cenozoic nannofossils. Both probabilistic and deterministic methods of quantitative biostratigraphy are being used to define the most reliable bioevents. We are interested specifically in biostratigraphic variations that are related to differences in paleobiogeographic realm (both latitudinal and inter-oceanic) and to position of depositional systems relative to proximity to shore. We are currently working with records from the Cenozoic of Antarctica and the Southern Ocean, the Paleogene of the temperate regions, and the Cretaceous of North America and the world ocean.
Calcareous nannoplankton are controlled strongly by the nature of the surface water mass they inhabit. This relationship exerts a primary control on their distribution and especially their abundance in fossil assemblages. We are using statistical and numerical analysis to derive the relationships of nannofossil abundance to surface water fertility and paleotemperature as a way to examine paleoceanographic change. We are currently looking at these nannofossil assemblage dynamics to explore the nature of cyclic sedimentation in the Upper Cretaceous and Paleogene. Oceanic anoxic events (OAE) are of special interest in this regard, as the large-scale storage of organic carbon during these times, important in the generation of hydrocarbon source beds, was driven at least in part by major changes in surface-water fertility.
Major perturbations in oceanic surface-water characteristics, such as OAEs and thermal excursions, can drive the rapid evolution of the plankton. We are looking at the detailed evolution of several groups associated with these major oceanic perturbations in an effort to understand and document the mechanics of evolutionary change from a geological perspective. This includes work within a single species (e.g., Axopodorhabdus biramiculatus) and within major clades (e.g., Eiffellithus). By using astronomically tuned records from the deep sea, we are able to define the precise timing of speciation events and track the rise and fall of species during intervals of rapid global change.
Blair, S.A., and D.K. Watkins, 2009, High-resolution calcareous nannofossil biostratigraphy for the Coniacian/Santonian Stage boundary, Western Interior Basin, Cretaceous Research, 30, 367-384, doi:10.1016/j.cretres.2008.07.016.
Shamrock, J.L., and D.K. Watkins, 2009, Evolution of the Cretaceous calcareous nannofossil genus Eiffellithus and its biostratigraphic significance, Cretaceous Research, 30, 1083-1102, doi:10.1016/j.cretres.2009.03.009
Browning, E. L., and D. K. Watkins (2008), Elevated primary productivity of calcareous nannoplankton associated with ocean anoxic event 1b during the Aptian/Albian transition (Early Cretaceous), Paleoceanography, 23, PA2213, doi:10.1029/2007PA001413.
Weber, R.D., and D.K. Watkins, 2007, Evidence from the Crow Creek Member (Pierre Shale) for an impact-induced resuspension event in the Late Cretaceous Western Interior Seaway, Geology, 35, 1119-1122.
Watkins, D.K., 2007, Quantitative analysis of the calcareous nannofossil assemblages from CIROS-1, Victoria Land Basin, Antarctica, Journal of Nannoplankton Research, 29, 130-137
Watkins, D.K., M.J. Cooper, and P.A. Wilson, 2005, Calcareous Nannoplankton Response to late Albian Oceanic Anoxic Event 1d in the Western North Atlantic, Paleoceanography, 20, 14 p., doi:10.1029/2004PA001097.
Watkins, David K., and J.M. Self-Trail, 2005, Calcareous nannofossil evidence for the existence of the Gulf Stream during the late Maastrichtian, Paleoceanography, 20, 9 p. doi 10.1029/2004PA001121.
Holmes, M.A., D.K. Watkins, and R.D. Norris, 2004, Paleocene cyclic sedimentation in the western North Atlantic, ODP Site 1051, Marine Geology, 209, 31-43.
Watkins, D.K., and J.A. Bergen, 2003, Late Albian adaptive radiation in the calcareous nannofossil genus Eiffellithus, Micropaleontology, 49, 231-252.
Watkins, D.K., and G. Villa (2000), Palaeogene calcareous nannofossils from CRP2/2A, Victoria Land Basin, Antarctica, Terra Antartica, 7, 443-453.
Watkins, D.K., S.W. Wise, Jr., and G. Villa (2001), Calcareous nannofossils from Cape Roberts 3, Terra Antartica, 8, 339-346
John Sarao, M.S. 2009
Jamie Shamrock, M.S. 2008
Stacie Blair, M.S. 2006
Ryan Weber, M.S. 2006
Amanda Minert, M.S. 2005
Emily Browning, M.S. 2005
Todd Boesiger, M.S. 2005