16 November, 2015

A new study by an international team of scientists, including from British Antarctic Survey (BAS), has analysed the effects on seabed communities of glacial retreat. Writing in Science Advances this week, the team say they have found significant changes in the biodiversity of an area of King George Island which has witnessed a major reduction in sea ice over recent years. The island is part of the South Shetland archipelago just north of the Antarctic Peninsula.

Led by marine ecologist, Ricardo Sahade, from the University of Cordoba in Argentina, the team repeatedly surveyed Potter Cove in Maxwell Bay over a period of 16 years. They found that over time the dominant life on the seabed switched to species that were more tolerant of sediments. The cove’s waters have got murkier from mud-laden melt water and icebergs resuspending sediments as they carved off from retreating glaciers.

Dr. Sahade, the lead author on the study, says:

“Establishing baseline data is crucial, against which we can attempt to measure change. However, in the Southern Ocean we have had to do that comparatively recently. We worked hard to document how much of which species lived where in our first scuba diving expeditions to Potter Cove back in 1994.”

The South Shetland Islands
The South Shetland Islands

A scientist from BAS helped interpret the data recovered from King George Island. Ecologist, Dr. David Barnes says:

“Carlini is one of the few Antarctic research stations where you can monitor life on the seabed by scuba diving, and that has proved important. Our collaborations involving Argentinian, German and British diving scientists have shown that to survive rapid glacier retreat creatures need to be very tolerant of sediment.”

While the likely effects of climate change on open-water species, such as fish and krill, in the Southern Ocean have been well documented, the changes that could impact on benthos, or seabed communities, haven’t been investigated so well. This new study suggests there could be significant alterations in these communities.

The Dallmann laboratory at Carlini Station is a platform for ecosystem research and started out as a joint project of the Argentine Antarctic Institute (IAA) and Germany’s Alfred Wegener Institute (AWI).

The paper: Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem is published by Science Advances