OREANDA-NEWS Alongside collaborators from the Plymouth Marine Laboratory and the University of Washington, St. Louis, the team from Oxford’s Earth Sciences Department studied coccolithophores, single-celled algae that live on carbon dioxide, water and sunlight.

Some plankton are known for making shells whose chemistry records the environment they live in. As a species, coccolithophores are distinct from other algae, as they produce their shells, and the chemistry contained within their shells, entirely within the cell. Their microscopic, mineralised plates (known as coccoliths) contain a chemical imprint of the cell, as well as the environment, and leave a different and highly variable chemical signal in the sediments preserving them.

Scientists have long been able to measure these chemical signals, and limited evidence about how much environmental and physiological conditions impacted the chemical imprint of these ancient plankton has previously made it very difficult for them to interpret the data. But the new findings, published in the journal Nature Communications, could change that.

By observing that the algae’s chemical signature was species-specific, and dependent on the rate at which they grow and calcify, they have found direct links between the chemistry of the coccoliths, the physiology of plankton, and their external environments. Studying these differences in more detail could shed light on prehistoric ocean conditions and help scientists gain further understanding of how sensitive the Earth is - or was-to carbon dioxide and how much, and how drastically, the climate changed during this time.

Their findings not only support understanding of individual algal physiology and evolution, but also the geological fossil patterns and chemistry that have been observed throughout history.