Title: Reconstructing paleoproductivity in the vicinity of the Azores Islands using coccolith assemblages
Description:
The study aims to reconstruct paleoproductivity in the midlatitude North Atlanic. Furthermore possible relations to changes in paleoclimate and/or changes in AMOC (Atlantic Meridional Overturning Circulation) should be investigated. Therefor coccolith assemblages will be used. There are two reasons for this: 1. coccolithophorids are one of the three major primary producers in todays world oceans and hence they are perfect for paleoproductivity estimates. 2. due to photosynthetic activity and calcification processes the impact the oceans organic and inorganic carbon pump.
The studies are conducted on sediment cores obtained slightly south of the Azores Islands. The core location corresponds to the northern margin of the subtropical gyre (SG). Therefore we might have the opportunity to reconstruct the extend of the SG.
Today primary productivity in the SG is very low ("oceanic desert") but their area is quiet large. Threfore the extend of the SG might be an important feedbackmechanism for climate changes.
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SEM pictures of coccoliths in the investigated sediment cores. 1.) coccolith of Emiliania huxleyi (magnification: 12000); 2.) coccosphere of Gephyrocapsa muellerae (magnification: 10000); 3.) from left to right: F. profund, U. tenius and C. mediterranea (magnification: 10500).
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