There are discoveries that are not made every day, and in some way they mark a watershed. The one just done by a research team north of Antarctica certainly is. Scientists have recovered fragments of DNA dating back 1 million years.
Found at the bottom of the Scotia Sea in Antarctica, these fragments of organic material can be a priceless treasure. They will allow us to trace the history of this part of the world, what lived in the ocean and what time span it covered.
A million times useful
Technically it is this: the sedaDNA (otherwise called “ancient sedimentary DNA”) is million-year-old material that could also play a useful role in ongoing efforts to understand how climate change might affect Antarctica in the future.
“It is by far the oldest marine sedaDNA authenticated to date,” says the marine ecologist Linda Armbrecht from the University of Tasmania in Australia, who contributed to the study.
SedaDNA
To put this in order, SedaDNA is found in many environments, including terrestrial caves and subarctic permafrost. In the past it is there that the oldest finds were made, dating back to 400.000 and 650.000 years ago respectively.
How was it possible to unearth a million-year-old fragments? Low temperatures, low oxygen levels and a lack of UV radiation have made polar marine environments such as the Sea of Scotland terrific places to keep sedaDNA intact. It just had to be found.
And it happened in 2019, think. It took a full three years to put the material through a comprehensive contamination control process to ensure the age markers within it were accurate. Quite a coup, in the past it would have taken at least 10 years. Scientists are constantly improving techniques to remove these ancient DNA fragments from the soil and the “noise,” the interference of all the modern DNA that has subsequently settled.
A treasure chest of time
Among other findings, the team discovered diatoms (single-celled organisms) that date back 540.000 years. Other elements that help improve the vision of how this part of the world has evolved over so long.
From the calculations made and presented in the study published in Nature Communications (I link it here) the last “warm” period in the Scottish Sea appears to date back to around 14.500 years ago.
“Antarctica is one of the most vulnerable regions to climate change on Earth,” the conclusions read, “and studying the past and present responses of this polar marine ecosystem to environmental change is an urgent matter.”
So much so that someone wants to cool the poles spraying them with aerosols from the sky with planes, but that's another story.
