The collapse of large ice shelves on the Antarctic Peninsula has allowed a group of researchers to discover new submarine communities in extreme environments under the Antarctic ice cap. The edition of the American journal EOS, published by the American Geophysical Union, released on 19 July, reports the discovery on the basis of the results of a scientific expedition that involved the researcher Verònica Willmott, a member of the Marine Geoscience Research Group at the Universitat de Barcelona (UB); a group associated with the Parc Científic de Barcelona.

The discovery occurred in March during a marine geological expedition in the area of the Larsen B shelf, on the east coast of the Antarctic Peninsula, on board the oceanographic vessel Lawrence M. Gould. Directed by the geologist Eugene Domack (Hamilton College, New Yorlk), the expedition aimed to study the marine sediments in the zone that was previously covered by ice. The collapse of the shelf, which is more than 30 metres thick, has attracted the interest of the international scientific community in recent years. At present, evidence supports the notion that the shelf collapse has occurred as a result of climatic change and global warming.

The collapse of the ice shelf has opened up a new area for research as the vessel Lawrence M. Gould was able to enter areas that were previously inaccessible. These unknown areas have provided unexpected results. “Through sea bottom video coverage, we have obtained images of biological communities that live under the ice cap at a depth of 850m. Specifically, we have observed communities of bivalve molluscs of more than 20 cm in diameter that are able to grow and develop in these extreme habitats.” The submarine images also have shown volcanoes and microbial mats.

“This is the first time that marine communities have been identified on the sea bed beneath an ice shelf”, commented the senior professor Miquel Canals, head of the Marine Geoscience Research Group at the UB. The presence of these biological communities is related to the emission of gases from the sea bed. According to the authors, methane released from the sea bed could provide an energy source for the organisms that inhabit depths of more than 800 metres.

Furthermore, the collapse of the shelf, which acted as a protective barrier, opens up many questions regarding the future of these Antarctic bed communities. “”We know that the break up of the ice has totally destabilized the natural ecosystem of these biological communities, which is of great concern”, explained Verònica Willmott. From now on, sediment build up may affect the delicate environmental balance of the sea bed and of the organisms that live there, which, until now, were protected by the layer of ice. “In fact, we are now studying whether shelf collapse is a recurring phenomenon,” she added.

According to the research team, future expeditions will contribute to identifying previously unknown species and to improving our knowledge of extreme habitats in the poles and their relation with oceanic circulation and climatic change.