# Diatom lipids open window to past ocean temperatures in the polar regions

## TL;DR

A new method using diatom lipids can accurately reconstruct past ocean temperatures in polar regions, improving climate change studies.

## Contribution

A single calibration for a diatom lipid-based proxy to reconstruct sea surface temperatures in both Arctic and Antarctic regions.

## Key findings

- The proxy works for temperatures between −1 and 14 °C in polar regions.
- The method is applicable to sediment archives spanning recent decades to the Younger Dryas/Holocene.
- A 750 kyr temperature record was reconstructed from the Fram Strait.

## Abstract

Sea surface temperature is a key indicator of climate change on Earth and is central to all related modelling endeavours. However, sea surface temperature is notoriously difficult to reconstruct accurately in the geological record, especially for the low temperatures of the polar regions, which occupy one-third of the world’s oceans. Here we show that a sea surface temperature proxy based on two isomeric diatom lipid biomarkers can be applied to marine sediment archives to reconstruct temperatures in the range −1 to 14 °C for the Arctic and Antarctic using a single calibration. For both regions, our datasets span timeframes from recent decades to the Younger Dryas/Holocene, and we also showcase a 750 kyr record from the Fram Strait, the major gateway between the North Atlantic and the Arctic Ocean. We anticipate that this lipid biomarker-based proxy may become a standard component of the palaeoclimate toolkit, especially for the polar regions.

A biomarker sea surface temperature proxy based on two isomeric diatom lipids can reconstruct a range of sea surface temperatures for both the Arctic and Antarctic Oceans, according to analyses of sea surface temperature reconstructions across polar seas