MELBOURNE, FLA.—Climate change could cause a major ecological upheaval in the shallow marine waters of the continental shelf of Antarctica. This is the outlook according to Professor Richard Aronson, head of the Florida Institute of Technology Department of Biological Sciences. His research finds predatory crabs poised to return to warming Antarctic waters and disrupt the primeval marine communities that have lived there for millions of years.
Aronson just received $760,000 in a second round of funding from the National Science Foundation (NSF) for his research. The grant will support two oceanographic cruises, planned for the 2013-2014 and 2014-2015 austral-summer seasons, to chart the progress of the invasion. The grant is from the NSF Antarctic Organisms and Ecosystems program, which is part of the Division of Antarctic Sciences within the Office of Polar Programs.
Aronson sees cause for concern."The king crabs are predators that eat most types of hard-shelled prey. If the crabs make it onto the Antarctic shelf, it is highly likely they will disrupt the unique seafloor communities, which currently live just a few hundred meters shallower than the massed crab populations," he said. Although king crabs are a commercially harvested elsewhere, Antarctica is too remote and the crabs are too small for a viable fishery.
The shell-cracking crabs, fish, sharks and rays that dominate bottom communities in temperate and tropical zones have been shut out of Antarctica for millions of years because it is simply too cold for them.
But this situation is about to change. "Populations of predatory king crabs are already living in deeper water," said Aronson. "And increasing ship traffic is introducing exotic invaders all the time. When ships unload ballast water in the Southern Ocean that surrounds Antarctica, larvae from all over the world get introduced to the ecosystem."
Antarctica's coastal waters are warming rapidly. Temperatures at the sea surface off the western Antarctic Peninsula went up 1°C in the last 50 years, making it one of the fastest-warming regions of the World Ocean.
"If the crabs invade, they will devastate Antarctica's unique shallow-marine fauna," said Aronson. "Unless we work to slow greenhouse-gas emissions, climate change over the next several decades will accelerate the crab invasion and threaten the marine communities in Antarctica. Those communities will lose their unique demeanor and come to look like seafloor communities everywhere else. Taken together, the world's marine ecosystems will be less diverse. We will have lost something unique and truly beautiful."
NOTE: Dr. Aronson is available for interviews.