Project Details
Projekt
Oligocene calcareous nannoplankton community dynamics and Pacific Ocean marine ecosystem function
Applicant
Dr. Rosie Sheward
Subject Area
Geology
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 447581699
Coccolithophores and calcareous nannoplankton have been the dominant calcifying marine phytoplankton group for much of the last ~200 million years, during which time they have evolved under substantial long- and short-term global climate upheavals. The characteristics of coccolithophore communities during warm periods on different background states provides critical windows into the possible responses of extant species to the shifts in environmental conditions that future climate change will bring. The challenge is retrieving information from fossil assemblages that brings us closer to understanding them as communities of short-lived individuals, where fitness and the trajectory of biological success are driven by cellular requirements and physiology. Traditionally, this perspective is the scope of biologists not micropaleontologists. However, a rich archive of calcite cell coverings – coccospheres – preserved intact within the fossil record allows us to access exciting new information about the living cell, including its size, biomass, calcite, ontogeny, and growth phase. This research project proposes to use innovative new methods to reconstruct the size and biogeochemical characteristics of coccolithophore communities in the Pacific Ocean during the ‘warm’ icehouse of the Oligocene. To achieve this, new records of Oligocene coccosphere morphology and cell size will be generated at Site U1553, recovered in the high-latitude South Pacific Ocean in January 2020. Combined with records of coccolith size and assemblage relative abundance, community size structure, biomass and calcite production will be reconstructed. Community size structure will also be reconstructed at a mid-latitude and two low latitude Pacific sites to investigate the role of latitudinal temperature and nutrients gradients in structuring communities. The unique cellular perspective used in this project will reveal how the changing presence of different species through past warm intervals drives shifts in biomass and calcite production that are highly relevant for understanding ecosystem and biogeochemical change in modern phytoplankton communities.
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