Marine diatom fossils in the Transantarctic Mountains have long puzzled scientists. Researchers wondered how these fossilized algae ended up in the Antarctic mountains and many were divided between two leading theories. Now a new paper drawing on new data suggests both theories may be partially correct, with implications for sea level rise today.

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The diatoms are from the Pliocene Epoch, and date to around 2.6 million to 5.6 million years in the past. One theory suggested the diatoms may have found their way to mountain rocks when the East Antarctic Ice Sheet melted in a Pliocene warm period. When the ice reformed into glaciers, the glaciers brought the diatoms to the mountains. The other theory suggested the diatoms were actually buffeted into the mountains by wind.

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Four scientists from Northern Illinois University, the University of Massachusetts Amherst, and Pennsylvania State University reported “new atmospheric modeling utilizing Pliocene climate and derived Antarctic landscapes” to unite the theories in a paper published online this week by Nature Communications. From the new data, the scientists think the East Antarctic Ice Sheet did retreat, by 300 miles, but wind still helped with the mysterious transportation of the diatoms. As the ice melted, “diatom-rich lands” were exposed to wind, which ferried the diatoms to the mountains instead of glaciers doing the job.

The paper’s lead author, Reed P. Scherer of Northern Illinois University, told Popular Science, “The rise in atmospheric carbon dioxide from burning fossil fuel has now elevated the concentration to 400 parts per million, matching for the first time the levels of the warm Pliocene.” As climate change today leads to sea level rise, the fate of precarious Antarctic ice sheets becomes of greater concern. When the ice sheets melted back in the Pliocene, ocean levels could have been 75 feet higher than today’s levels – a dangerous prospect.

Via Popular Science

Images via Wikimedia Commons and Reed P. Scherer, Robert M. DeConto, David Pollard, and Richard B. Alley