Million-year-old marine DNA may reveal how climate change will affect Antarctica

Scientists have unearthed fragments of deoxyribonucleic acid, also known as DNA, from the Scotia Sea, north of the Antarctic continent. DNA is a million years old and is used to study the responses of ocean ecosystems to climate change.

A study, conducted by researchers from the University of Tasmania and the University of Bonn discovered ancient sedimentary DNA (sedaDNA).

SedaDNA analysis is a new technique that helps decipher ‘who’ has lived in the ocean in the past and ‘when’. It can help study the long-term responses of ocean ecosystems to climate change, as the study demonstrates DNA from ancient marine sediments reveals diatom transition in Antarctica.

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The study, published in the journal Nature Communicationcan also help assess current and future changes in marine life around Antarctica.

Antarctica is one of the most vulnerable regions to climate change on Earth, so it is essential and urgent to study the past and present responses of the frozen continent to environmental and climate change.

Antarctica is arguably the most climate-sensitive polar region, as evidenced by the fact that West Antarctica is one of the fastest warming regions in the world, according to the study.

Understanding how organisms in the Southern Ocean respond to climate variability, including during past climate change, is therefore of critical importance in predicting how the Antarctic marine ecosystem will evolve in the near future, adds Dr. ‘study.

An international team studied the sediments acquired during the International Ocean Discovery Program, a multi-rig international research program. The samples were collected during Expedition 382 in 2019, called Iceberg Alley and Subantarctic Ice and Ocean Dynamics.

Study of characteristic age-related damage patterns in recovered DNA fragments found them to be as old as a million years.

“This includes by far the oldest authenticated marine sedaDNA to date,” said senior researcher Linda Armbrecht from the University of Tasmania, Australia.

Among the organisms detected were diatoms as the main primary producers whose DNA was detected half a million years ago.

Diatoms were consistently abundant during warm climatic periods, data collected by the researchers showed. The last such change in the Scotia Sea food web occurred about 14,500 years ago.

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“This is an interesting and important change that is associated with a global and rapid rise in sea level and a massive loss of ice in Antarctica due to natural warming,” said Michael Weber, second author of the study. study by the University of Bonn.

Warming has apparently caused an increase in the productivity of the oceans around Antarctica.

The study demonstrates that marine sedaDNA analyzes can be extended to hundreds of thousands of years, paving the way for the study of ecosystem-scale marine changes and paleo-productivity changes throughout many glacial cycles.

These periods of natural climate change can also provide insight into current and future human-induced global warming and how the ecosystem might respond to it.