Abstract
Cell geometry and size strongly determine the physiology of unicellular algae, whilst also affecting their ecological and evolutionary patterns. An overall macroevolutionary size decrease in coccolithophores, an important group of marine unicellular calcifying algae, is punctuated by distinct size responses that correlate to major climatic and paleoceanographic events during the Cenozoic (the last 65 million years). Coccolithophorid cell size – as reconstructed from individual fossil 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.
During this seminar, I will present biometric data of various coccolithophore 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. An apparent paradox, the fact that long-term patterns of coccolithophorid evolution and success seem counter-intuitive to the modern paradigm of low calcification under high pCO2 and ocean acidity, will also be discussed.
Other information
The CEES seminar room has a coffee-machine – it is therefore recommended that you come a bit earlier and get yourself a good cup of coffee (for the price of 3 NOK).