One-million-year-old DNA from deep-sea beds north of Antarctica will help predict how marine life will respond to climate change.
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The marine sedimentary ancient DNA, known as sedaDNA, was retrieved from up to 178m below the sea floor in the Scotia Sea as part of an international study led by the Institute of Marine and Antarctic Studies.
"The fragments are the oldest authenticated marine sedaDNA discovered to date," said Linda Armbrecht, researcher at the institute and lead study author.
"These have been preserved due to factors like very low temperatures and oxygen concentrations, and an absence of UV radiation."
Among organisms in the sediment were diatoms, a type of phytoplankton that are the basis of many marine food webs.
Dating as far back as 540,000 years ago, the diatom sedaDNA data showed they were consistently abundant during warm climatic periods.
"To analyse these fragments, we use a new technique ... which can help us decipher what has lived in the ocean in the past and when, across multiple ice-age cycles," Dr Armbrecht said.
"With this knowledge, we can better predict how marine life around Antarctica will respond to ongoing climate change."
Co-author Michael Weber from the University of Bonn in Germany said there was a change in the Scotia Sea's food web about 14,500 years ago.
"This interesting and important change is associated with a world-wide and rapid increase in sea levels and massive loss of ice in Antarctica due to natural warming - warming that apparently caused an increase in ocean productivity around Antarctica at that time," he said.
The research, undertaken during an International Ocean Discovery Program expedition, was published in the scientific journal Nature Communications.
Australian Associated Press
