Plankton evolution during peak greenhouse climates

Calcareous nannoplankton are microscopic marine algae that secrete calcitic cell coverings (coccoliths) which are preserved throughout the geographically-widespread pelagic sedimentary record. By studying calcareous nannofossil assemblages preserved within sediments we can document their evolution through time, including changing diversity, rates of speciation and extinction, and population compositions. Calcareous nannoplankton are very responsive to changes in environmental parameters, particularly sea surface temperature and nutrient availability, with individual species or groups exhibiting particular preferences for specific ecological niches. Using the quantitative abundance of species within an assemblage we are therefore able to reconstruct past environmental conditions for a specific location at a given time.

International Ocean Discovery Program Expedition 371 will drill deep-sea sediments in the Southwest Pacific Ocean, recovering cores which are from the Eocene epoch, a key interval in Earth's climate history marking the transition from very warm 'greenhouse' climates into a much cooler 'icehouse' world with large Antarctic icesheets. This profound interval of climatic change saw major shifts in physical, chemical and biological parameters in the marine and terrestrial realms. A series of rapid warming events, known as hyperthermals, characterise the early Eocene, followed by a long-term cooling through the middle and late Eocene. Calcareous nannoplankton, which were the dominant oceanic phytoplankton group at this time, peaked in diversity but then suffered a major decline and underwent significant population change coinciding with this major climatic reorganisation. However, the precise timing and structure of this evolutionary change is still poorly known. In this research we will produce calcareous nannoplankton assemblage records (diversity and population data) in order to determine the relationship between nannoplankton evolution and palaeoclimatic and palaeoceanographic change in the South West Pacific.

The data and research produced during this research will be of interest to a wide range of end-users and published and made accessible in a variety of formats

Expedition reports. Shipboard nannofossil results will immediately be incorporated into the Expedition 371 reports, which will be published as open access Preliminary Report and Proceedings of the IODP volumes.

Public knowledge transfer activities. The IODP has a strong program of shipboard educational activities and Dr. Newsam will actively work with the educators onboard ship and participate in the public awareness and outreach programme, which will include broadcasts to schools, videos and web-based outreach. She will also provide information about life as a shipboard biostratigrapher via the UCL Earth Sciences Twitter account.

Nannotax online resource. Stratigraphic and taxonomic data (including fossil images) will be given the widest access via the online Nannotax resource (http://www.mikrotax.org/Nannotax3/), which is managed by the PI Prof. Bown at UCL. This online resource has global reach to a wide range of end-users (industrial and academic stratigraphers, school and university students, etc.) and has excellent usage statistics as evidence by Google Analytics, e.g., ca 1300 user sessions a week, of average duration 13 minutes. We will use results from this project to hence the resource, particularly through the production of high quality light microscope images of Paleogene nannofossil taxa.

Publications and presentations. The post-expedition research will be disseminated through open access publications and scientific presentations. We plan to present our results to the UCL student geological society (the Greenough Society), the UK IODP Newsletter and at national and international conferences, e.g., in the immediate post-expedition interval we plan to attend The Micropalaeontological Society meeting in November 2017.