HR: 16:15h
AN: OS14A-02    [Abstracts]
TI: Cenozoic Icehouse Forcing Mechanisms on Coccolithophorid Evolution
AU: * Henderiks, J
EM: jorijntje.henderiks@geo.su.se
AF: Dept. of Geology and Geochemistry, Stockholm University, Svante Arrheniusvag 8C, Stockholm, SE-106 91, Sweden
AB: An overall macroevolutionary size decrease in marine unicellular calcifying algae, the coccolithophores, is punctuated by distinct size responses that correlate to major climatic and paleoceanographic events during the Cenozoic. Notably, major size decreases in the ancestors of the modern blooming species Emiliania huxleyi and Gephyrocapsa oceanica are recorded at the Eocene-Oligocene transition (34 Ma) and in the late Miocene (9 Ma). Coccolithophorid cell size (as reconstructed from individual coccolith biometry) is likely influenced by a variety of passive and active evolutionary selection pressures, with specific factors, such as resource availability and climatic change, determining trends in specific intervals of time. This study presents biometric data of the Noelaerhabdacaea, Calcidiscaceae and Coccolithaceae families, which together represent the bulk of coccolith-carbonate buried in Cenozoic deep-sea sediments, from multiple Deep Sea Drilling Project and Ocean Drilling Project sites covering temperate to tropical regions in the Atlantic, Indian and Pacific oceans. Despite distinct regional ecologic responses at each site, striking correspondences within the global data set call for global forcing mechanisms on the size evolution and ecological success of coccolithophores in an ‘icehouse' world.
DE: 0444 Evolutionary geobiology
DE: 1630 Impacts of global change (1225)
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4944 Micropaleontology (0459, 3030)
DE: 9604 Cenozoic
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting