Discovery of the oldest sedimentary DNA authenticated to date in Antarctica!

Scientists have discovered DNA fragments dating back a million years under the floor of the Scotia Sea, north of Antarctica. These small pieces of organic material can be very valuable for tell the story of the region. They make it possible to identify the species that lived in the ocean and the time they spent there.

These ancient sedimentary DNAs are called sedaDNA. Scientists believe recovered samples could be used to understand how climate change would impact Antarctica in the future. The study was published in the journal Nature.

Discoveries that have made it possible to better understand the evolution of this region

Sedimentary DNA is present in several environments. Terrestrial caves and subarctic permafrost yielded sedimentary DNA dating back 400,000 and 650,000 years, respectively. However, the DNA unearthed in Antarctica is oldest marine sedimentary DNA certified to date. The fact is that climatic conditions and low oxygen levels in polar marine ecosystems are favorable for the preservation of sedaDNA.

The collected DNA was taken from the ocean floor in 2019. It has undergone a complete contamination control process in order to authenticate the age markers. The other results revealed diatomsunicellular organisms dating from 540,000 years ago. These discoveries have made it possible to better understand the evolution of this part of the world over a long period.

The team identified the relationship between the abundance of diatoms and the hottest periods. For the Scotia Sea, the last dates back to about 14,500 years ago. This caused a increase in overall marine life activity throughout the Antarctic region.

“This is an interesting and important change that is associated with a global and rapid rise in sea levels and a massive loss of ice in Antarctica due to natural warming. »

Geologist Michael Weber from the University of Bonn in Germany

Understanding the past to preserve the future

This study showed that these sedimentary DNA techniques could contribute to the reconstitution of ecosystems over hundreds of thousands of years. This has made it possible to better understand the evolution of the oceans. The technique of extracting ancient fragments continues to progress. By isolating ancient DNA, it offers a authentic insight into the past.

Climate change will heavily affect Antarctica. This is why it is essential to understand past climate change and how the ecosystem reacted. Thus, researchers will be able to accurately anticipate what could happen around the South Pole.

SOURCE: SCIENCEALERT