Astronomical pacing and tipping points in phytoplankton productivity and evolution in a warm world

Phytoplankton forms the basis of life in the ocean, drives chemical cycles and produces vast amounts of oxygen. The production of organic matter by phytoplankton in the surface ocean is commonly referred to as marine productivity.

Sediments recovered from the bottom of the ocean by the International Ocean Discovery Program (IODP) provide the most continuous records that can reconstruct major fluctuations and abrupt changes in marine productivity during past warm intervals of Earth´s history.

This project focuses on the early-to-mid Pliocene (5.3-3.2 million years ago), a geological period that offers a great past analogue for future global warming.

The analysis includes previous IODP drilled sites, as well as recently recovered sediment cores from the north Atlantic (IODP Expeditions 395C and 395).

Initially, this research investigates the imprint of Earth´s astronomical cycles (eccentricity) on a global compilation of marine productivity records, as well as on the morphology of coccolithophores, an important calcifying phytoplankton group.

Following that, abrupt, sustained changes in marine productivity and coccolithophore evolution are identified, and their possible link to the rhytmical fluctuations controlled by astronomical cycles is evaluated.

By documenting the pace and the mechanisms behind such changes in a warmer than present world, we can better understand current conditions and the ongoing anthropogenic impact on phytoplankton productivity.