Drivers of extinction in the marine phytoplankton

Marine phytoplankton form the basis of pelagic food webs and ecosystems. With modern anthropogenic environmental impacts - including eutrophication, climate change and ocean acidification - there is evidence that this group is already experiencing biogeographic range shifts and changes to community structure. The longer-term risk of species extinction within this group is, however, more poorly understood. Here, we seek to investigate the dynamics, causes and community restructuring during a major extinction of a closely-related group oceanic surface-dwelling alage, approximately 2 million years ago.

The alage concerned produce calcium carbonate (calcite) plate-like scales, which are produced by and surround the cell during life, but on death accumulate in great numbers in deep ocean sediments. These fossil scales, called coccoliths, can be used to reconstruct the abundance and diversity of species that were living in the surface ocean across millions of years. The chemistry of coccoliths can also be used as an indicator of cell processes and the conditions in the surface ocean environment at the time the coccoliths were formed. Togther, we propose to use the variations in abundances and diversity of species, as well as chemical indicators of cell growth rates and environment, to determine the main drivers of species extinction in this case. In particular, was this mainly driven by biotic competition with other algal species and groups, or was it due to changing surface ocean environments, which drove the loss of the particular niche occupied by the extinct species. Understanding this process, will help constrain the dynamics of extinction in the plankton, and the mechanisms by which environmental stress is transferred into extinction risk.

INDUSTRIAL IMPACT
This project is directly related to the CENTA NERC DTP PhD project, awarded to Amy Jones, focusing on the patterns of evolution and extinction within late Neogene coccolithophore communities. This project includes supervision from external partners Network Stratigraphic UK, a significant provider of biostratigraphic consultancy services within the UK and globally. Amy's project will include placement time at Network Stratigraphic, where she will be able to gain the view of highly experienced industrial biostratigraphers on the taxonomic differentiation and key biostratigraphic events through this interval. Although industry has a key focus on stratigraphy, this is fundamentally based on robust bioevents, which can be correlated across basins and be picked reliable on the basis of sound taxonomic differentiation. In this project, we seek to make use of this expertise in setting key target bioevents. We will then use the high precision age models that are only possible from IODP quality ocean sediment cores to test the patterns and processes driving these events. This understanding will, in turn, feedback into industrial applications, with the improved independent testing of assumptions about the synchrony of biostratigraphic events and additional details of nannofossil assemblage change, constrained by orbital age models, that could be used in applied stratigraphy.

EDUCATIONAL and STAKEHOLDER IMPACT
The science around IODP scientific ocean drilling is an ideal framework for engaging the wider public in the topics of Earth System Science and environmental change. The science objectives of IODP Expedition 363 address a range of key questions about current global change - monsoonal climate systems, long-term El Niño dynamics, tropical atmospheric circulation and precipitation regimes, and the dynamics of the Earth's cryosphere. Together with the specific focus of this project on extinction mechanisms in the oceanic ecosystem, this provides a range of topics of societal relevance on which to engage the public. All of these are set against the background of large-scale international scientific collaboration and major engineering and technological challenges all set within the context of the oceanic environment. This strong aesthetic appeal gives scientists leverage for communicating their work to the public, including young people, educators and policy makers. We will make use of this outreach opportunity within the context of the Heritage Lottery funded refurbishment of the Lapworth Museum of Geology. We will use this space to host outreach events focused on long-term climate change. This will link directly to the new climate section of the Active Earth galleries of the Museum. In progress already are video link-ups from Expedition 363 with a number of primary, middle and secondary schools, as well as University of the Third Age study groups hosted at the Lapworth Museum.

This moratorium proposal will fund a technician post, likely to be taken-up by a recent graduate of the MSc in Applied and Petroleum Micropalaeontology at Birmingham. This research experience, including laboratory preparation and analytical techniques, will provide them with positive experience for future work in either research or industrial micropalaeontology, with a potentially lasting impact on their education and career.