Marine DNA was found a million years old in Antarctic sediments

Marine DNA was found a million years old in Antarctic sediments

In a new study conducted by the University of Tasmania, with the participation of the University of Bonn, scientists discovered ancient marine DNA in the deep sea sediments of the sea of Scottia, north of the Antarctic continent.

This age means that sedimentary DNA will help to examine the long-term response of ocean ecosystems to climate change, as well as to assess current and future changes in marine life around a frozen continent.

Antarctica is one of the most vulnerable regions to global warming on Earth, so studying the past and present response of the polar marine ecosystem to environmental and climate change is critical and urgent.

The analysis of ancient sedimentary DNA is a new method that helps to decipher who lived in the ocean in the past and when. In addition, times of major changes in composition may be linked to climate change, and such knowledge will be useful in predicting the future of marine life around Antarctica.

An international group of scientists used sedaDNA to investigate changes in the structures of marine organisms in the sea of Scottia over the past million years. They used sediments from the 382nd IODP expedition, "Alley iceberg and sub-antarctic dynamics of ice and ocean", in 2019, to make sure that sedaDNA signals were genuine, including, for example, a study of age patterns of damage in recovered DNA fragments.

"This is certainly the oldest authentic sea sedaDNA today," explains Dr. Linda Armbrecht, leading researcher from Tasmania University, Australia.

Among the organisms detected were diatomies as the main primary producers, whose DNA had been detected for half a million years, and data showed that diatomic algae were abundant in warm climatic periods and stable in number.

The last such change in Scotty's food web occurred about 14,500 years ago, and scientists linked it to a worldwide and rapid rise in sea level and massive loss of ice in Antarctica due to natural warming, which led to an increase in ocean productivity around the mainland.