Marine microfossil networks: ancient and future community dynamics at the base of the food chain

Marine communities are becoming increasingly disrupted due to anthropogenic climate forcing.

These changes are typified by biogeographic range shifts, global biomass declines, community restructuring, and detrimental biological modifications and alterations to organism functionality.

It is therefore increasingly pertinent to understand how global marine communities will respond as climate continues to change, and to identify potential tipping points in marine biodiversity which may trigger the collapse of ecosystems beneficial to the livelihood and nutrition of billions of people around the globe.

In the modern ocean, the biodiversity distribution of the single-celled protists, the planktonic foraminifera, matches that of organisms fundamental to human populations, such as tuna, squid, and billfish.

Novel studies employing networks on the unmatched fossil record of the planktonic foraminifera indicate an equatorward shift in functional communities during the last 8 million years, due to global cooling, whilst other observations now suggest species populations have already begun to shift poleward from their pre-industrial distributions.

This poleward shifting may suggest entire food webs may shift poleward, or collapse altogether.

We will expand these novel network applications within the planktonic foraminiferal fossil record by applying these methods to all microplankton records (coccolithophores, radiolarians, diatoms, dinoflagellates) to determine the nature of these community shifts to late Cenozoic climate changes.

Following this, we will then assess and compare the community patterns of the Last Glacial Period and the pre-industrial Holocene records to determine the abiotic drivers of these distributions.

Finally, using ocean models of multiple anthropogenic emission scenarios, we will determine how the structure of global communities may become altered in the near future.