A one degree Celsius rise in local sea temperature may cause the Antarctic marine community to experience an unexpectedly high level of growth along with a reduction in diversity, a study suggests. Researchers at British Antarctic Survey in the UK deployed heated panels on the seabed on the Antarctic Peninsula to observe the effect on local marine species.
They observed that with a one degree Celsius rise in sea temperature, predicted by the Intergovernmental Panel on Climate Change (IPCC) to occur before 2100, the growth of Antarctic seabed life nearly doubled. The team noted that species richness, the number of different species represented in a community, remained the same under warming, although diversity and evenness of the community was reduced. Organisms on the seabed in Antarctica live in a very cold and stable environment where annual temperatures vary only between minus two and one degree Celsius. The environment has been this cold for millennia, and so marine life has become highly adapted. Understanding how future environmental change will affect the polar biodiversity in the ocean is key, as species may either benefit from or be damaged by small changes in sea temperature, researchers said.
They monitored the settlement and growth of organisms on the panels using high-resolution photography acquired by divers working in the frigid Antarctic water. The animals that settled on the panels include colonial bryozoans and spiral tube worms, both common to seafloors globally, researchers said. Increased growth may be a positive ecosystem response, nutrients would be more quickly available to species further up the food chain, while increased skeletal growth would increase carbon capture to the sea floor, they said. “Such large changes in communities, in response to conditions that are forecast within our lifetimes, is quite remarkable,” said Simon Morley an ecophysiologist at British Antarctic Survey in the UK. “Much of the biodiversity in the oceans is attached to the sea floor and these communities are clearly susceptible to even small changes in their environment. “Understanding which species will be the winners and losers is key as we try to predict the impact of climate change on life in the ocean,” Morley added. The study was published in the journal Current Biology.