|Description:||This thesis addresses several questions concerning modern planktonic foraminifera in the Atlantic Ocean. The vertical and lateral distribution of living planktonic as well as the chemical characteristics of dead and living species, population dynamics, deposition flux and seasonal variations were considered.
The geographical distribution of planktonic foraminifera is, above all, related to water temperature. On the other hand, the vertical distribution is much more differentiated and governed by an interaction of physical, biological and chemical parameters. Chemical entities are also imprinting foraminiferal shells during their ontogenesis and thus, make the foraminifera a signal carrier for environmental and paleoceanographical proxies. Therefore, this thesis focused on biogeographical studies and on chemical aspects to assess planktonic foraminiferal habitats and to improve our understanding of the role of planktonic foraminifera as environmental signal carriers. The present study focuses on three regions of the Atlantic Ocean, the seas to the west of Ireland, Cape Verde and central tropical Atlantic.