Potential methane reservoirs beneath Antarctica

The Antarctic Ice Sheet could be an overlooked but important source of methane, a potent greenhouse gas, according to research published today in Nature and conducted by an international team led by Professor Jemma Wadham from the University of Bristol's School of Geographical Sciences. The Antarctic Ice Sheet could be an overlooked but important source of methane, a potent greenhouse gas, according to research published today in Nature and conducted by an international team led by Professor Jemma Wadham from the University of Bristol's School of Geographical Sciences. The new study demonstrates that old organic matter in sedimentary basins located beneath the Antarctic Ice Sheet may have been converted to methane by micro-organisms living under oxygen-deprived conditions. The methane could be released to the atmosphere if the ice sheet shrinks and exposes these old sedimentary basins. The researchers estimate that 50 per cent of the West Antarctic Ice Sheet (1 million km2) and 25 per cent of the East Antarctic Ice Sheet (2.5 million km2) overlies preglacial sedimentary basins, containing about 21,000 billion tonnes of organic carbon. Team leader, Professor Wadham said: "This is an immense amount of organic carbon, more than ten times the size of carbon stocks in northern permafrost regions. Our laboratory experiments tell us that these sub-ice environments are also biologically active, meaning that this organic carbon is probably being metabolised to carbon dioxide and methane gas by microbes." The researchers then numerically simulated the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model.