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The Shifting Polar Ice Sheets

Posted October 21, 2011 @ 6:53pm | by TravelWild

The polar ice sheets are in the news lately and, fortunately, we have glaciologist Julian Dowdeswell of Cambridge University to explain their mysteries and importance in an animated and engaging way. This video gives a fascinating—and sobering—account of his work at both poles: studying the speed the ice sheets travel, using radar to determine the thickness of the Antarctic ice sheet and discovering subglacial mountain ranges previously unknown to scientists.

While science can seem tedious and esoteric at times, it sheds important light on what’s really happening under the surface, so to speak. Scientist Dr. David Barnes from the British Antarctic Survey (BAS) led a 25-year study of the effects of the faster rate of ice travel. He discovered a problematic cause-and-effect cycle of carbon release, warming and ice travel. The effect of icebergs melting means they move and travel, including along the sea floor, causing a disruption in the life cycle of the tiny bryozoans, which results in the bryozoans dying before reproducing. The dead bryozoans release their stored carbon, resulting in more carbon in the atmosphere—which means more greenhouse gases, which results in more climate change, melting more icebergs, causing them to break off and travel along the sea floor….

‘When icebergs smash into the seabed, it’s violent and very little survives that action. What we’re seeing is that these massive impacts on seabed biology are happening more and more frequently,’ he says. ‘It’s worrying, because these animals are struggling to reach maturity before they are killed off.’

Barnes and his co-author Terri Souster, who’s also from BAS, suspected that icebergs grinding against the seabed would harm marine life, but they found proving this far from easy.

They set up grids of 25 concrete markers at three different depths—at 5, 10 and 25 meters—on the seabed around Rothera research station. They then went back every year to inspect them to see how the seabed coped with so-called iceberg scouring.

‘Surveying just one grid could take a couple of days. You’ve got low visibility, leopard seals, not to mention freezing water, so it’s a lot of work in a challenging environment,’ says Barnes.

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