The breakup and collapse of the Larsen A ice shelf in the western Weddell Sea in 1995 has resulted in fundamental changes to life on the sea bed in less than two decades. As reported by biologists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in the cover story of the current issue of the scientific journal Current Biology, Antarctic glass sponges have been the prime beneficiaries of the disappearance of the ice shelf. To the surprise of the scientists, the density of these archaic filter-feeders has increased threefold between 2007 and 2011 despite only low plankton food supply and water temperatures of minus 2 degrees Celsius. The sponges had also grown remarkably quickly and had completely supplanted competitors for food. The results show that communities at the bottom of the western Weddell Sea react considerably more quickly to climate-related changes than previously thought.
Glass sponges (Hexactinellida), an archaic group of animals at the basis of the animal kingdom, dominate the shallow seafloor in the Antarctic. Many biologists believed that glass sponges grew so slowly that two-metre behemoths would have to be around 10,000 years or older. These assumptions have now been challenged in a new study led by scientists from the Alfred Wegener Institute (AWI) and published in the current issue of the scientific journal Current Biology.
During a Polarstern expedition to the poorly accessible region of the former Larsen A ice shelf, AWI biologists Laura Fillinger and Claudio Richter, together with colleagues from the University of Gothenburg and the Senkenberg Research Institute and Natural History Museum; succeeded in demonstrating that glass sponges can grow rapidly within a short period of time. "We were surprised by what we saw on our video screens in 2011 when we lowered our remotely operated vehicle onto the sea bed at a depth of around 140 metres. In an area, which had reve
|Contact: Sina Loeschke|
Helmholtz Association of German Research Centres