An international group of researchers led by the Institute of Marine and Antarctic Research at the University of Tasmania found ancient DNA in deep-sea sediments at the Sea of Skosh, north of Antarctica, which provides an insight into past changes in the ocean ecosystem and can help predict how marine life will respond to climate change.
Antarctica is one of the most vulnerable regions of the Earth to climate change; Western Antarctica warmed up 2.4 ± 1.2°C between 1958 and 2010, making it one of the fastest-heated regions in the world. "
The genetic traces of all organisms can potentially be preserved in sediment species. So far, the oldest authenticated sediment DNA has come from terrestrial sediments dated about 400,000 years ago and from subarctic sediments of permafrost dated about 650,000 years ago.
Traces of past climate events
The newly discovered ancient DNA was derived from sediment samples collected at a depth of 178 metres under the ocean floor at the sea of Skosha during the expedition of the International Ocean Opens Programme in 2019. "," says Dr. Linda Armbrecht, a researcher at IMAS and the lead author of the study, reporting on this discovery.
Using optimized extraction and new sediment DNA analysis techniques, researchers have been able to identify several organisms living in the ocean and report the discovery of sedimentary DNA from marine eukariate at least a million years old and sedimentary DNA from diatom algae and chlorophytes around 5400 years old.
Prior to the event, diatomic algae accounted for less than 10 per cent of all eukariotes, compared with about 50 per cent thereafter.
Towards the exploration of marine ecosystems over several glacier cycles
"," added Dr. Michael Webber of the University of Bonn Institute of Geoscience and co-author of the study.
However, researchers are cautious about this estimate because even under ideal storage conditions, ancient DNA is unlikely to last more than a million years.
However, this study shows that the DNA analysis tools for marine sediments
These natural climate change periods, recorded in sedimentary DNA fragments, can also provide insight into the current and future anthropogenic warming of the climate and how the ecosystem can respond to it.