How did plankton end up on top of Antarctica’s mountains?
Ars Technica » Scientific Method 2016-09-26
Since 1984, researchers have been arguing about what to make of tiny ocean plankton shells sitting atop the Transantarctic Mountains. That is obviously not a place plankton would call home, so how did they get there? And what might their presence tell us about Antarctica’s past?
The researchers who initially discovered the surprise diatom shells found them mixed in with glacially deposited sediment. They argued that the shells told a pretty big story. Around 3 million years ago, when these species of diatom were alive, we know there were several periods of climatic warmth. During these periods, the researchers said, the Antarctic ice sheets must have “collapsed” down to a much smaller size, opening basins in the interior of the continent that flooded with seawater. That is where these diatoms would have lived, piling up at the bottom of the seaway when they died.
When the climate cooled, the ice would have advanced back into these basins, scraping up diatoms and sediment and pushing it up against the Transantarctic Mountains—where it was perhaps lifted to even higher elevation by tectonic uplift of the landscape. This would require a much more dynamic ice sheet than most glaciologists expected, vulnerable to warmth that would drive serious melting and raise sea levels significantly.