ABSTRACT: Coccolithophores are one of the
most abundant groups of extant phytoplankton, they are significant components
of marine sediment, and they play a major role in marine primary production and
the oceanic carbon cycle. Until about forty years ago, the vast majority of
coccolithophore studies were focused primarily on taxonomy, zonation
development, and applied biostratigraphy. More recently, the coccolithophore
living and fossil record in the ocean and in the deep-sea sediments has been
used in paleoceanographic studies. These studies include using extant coccolithophore
assemblages as proxies for temperature and environmental change. In the fossil record, it is established to trace
changes in the nannofossil assemblages that are strictly linked to variations
in the physical and chemical properties of the waters such as salinity,
turbidity, temperature, nutrient content etc. In particular, different coccolith
taxa are known to be sensitive to specific environmental parameters.
The purpose of this seminar is to explain what these phytoplanktonic organisms are, why they are important and show how the coccolithophore assemblage variation can be used to characterize the dynamics of the different water masses in paleoceanographic studies. We will do this describing the International Ocean Discovery Program (IODP) and presenting results from the recent IODP Exp 339 (November 2011 to January 2012) in the Gulf of Cadiz and the West Iberian Margin. These regions are key locations for the investigation of Mediterranean Outflow Water (MOW) through the Gibraltar Gateway and its influence on global circulation and climate.