Scientists have discovered the world’s oldest marine DNA in Antarctica.
It could shed light on how life in the oceans has evolved over the last million years, while also offering clues as to how ocean ecosystems are affected by long-term climate change.
This is important because Antarctica is one of the most vulnerable regions to global warming on Earth.
The fragments of organic material were found beneath the floor of the Scotia Sea north of the Antarctic by a team of international researchers led by the University of Tasmania in Australia.
Technically referred to as sedaDNA – for sedimentary ancient DNA – the recovered samples are likely to help scientists understand how climate change could affect Antarctica in the future.
‘This comprises by far the oldest authenticated marine sedaDNA to date,’ said Dr Linda Armbrecht, the lead investigator from the University of Tasmania.
SedaDNA is found in many environments, including terrestrial caves and subarctic permafrost, where the material dates back up to 650,000 years.
Discovery: Scientists have found the world’s oldest marine DNA beneath the floor of the Scotia Sea (pictured), north of Antarctica
Recovery: Researchers extracted the DNA from the ocean floor in 2019
The reason places like the Scotia Sea allow sedaDNA to remain intact is because of the cold temperatures, low oxygen and a lack of UV radiation associated with polar marine environments
The reason places like the Scotia Sea allow sedaDNA to remain intact is because of the cold temperatures, low oxygen and a lack of UV radiation associated with polar marine environments.
Researchers extracted the DNA from the ocean floor in 2019.
It then went through a comprehensive contamination control process to ensure that the age markers embedded in the material were accurate.
Among the detected organisms were diatoms, or single-celled organisms, whose DNA was detected back to 540,000 years ago.
This was important because they allow scientists to better understand how this part of the world has evolved over vast expanses of time.
Researchers were able to link diatom abundance to warmer periods — the last of which in the Scotia Sea was around 14,500 years ago.
That led to an increase in overall marine life activity across the Antarctica region.
‘This is an interesting and important change that is associated with a worldwide and rapid increase in sea levels and massive loss of ice in Antarctica due to natural warming,’ said geologist Michael Weber, from the University of Bonn in Germany.
Among the detected organisms were diatoms, or single-celled organisms, whose DNA was detected back to 540,000 years ago
Researchers were able to link diatom abundance to warmer periods — the last of which in the Scotia Sea was around 14,500 years ago
This latest study is evidence that these sedaDNA techniques can be helpful in reconstructing ecosystems across hundreds of thousands of years, giving us a whole new level of insight into how the oceans have changed.
Scientists are steadily improving at removing these ancient DNA fragments from the ground and removing the ‘noise’ and interference left by all the modern DNA that’s been around since to get an authentic look at the past.
Understanding more about past climate shifts and how the ocean ecosystem responded means more accurate models and predictions for what might happen next around the South Pole.
‘Antarctica is one of the most vulnerable regions to climate change on Earth, and studying the past and present responses of this polar marine ecosystem to environmental change is a matter of urgency,’ write the researchers in their published paper.
The new study has been published in Nature Communications.
