Global warming aids invasive species in Antarctica - Summit County Citizens Voice

King crabs poised to invade the Antarctic continental shelf

Antarctic biodiversity is at risk from climate change. Photo by Bob Berwyn.

By Summit Voice

SUMMIT COUNTY â€" Global warming is on the verge of causing a major ecological upheaval in the shallow marine waters of Antarctica’s continental shelf, where predatory king crabs are poised to invade primeval marine communities that have lived there for millions of years.

“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,” said Richard Aronson, head of the Florida Institute of Technology Department of Biological Sciences.

Although king crabs are a commercially harvested elsewhere, Antarctica is too remote and the crabs are too small for a viable fishery, explained Aronson, who recently was awarded a $760,000 grant to study the progress of the invasion. The grant will support two oceanographic cruises, planned for the 2013-2014 and 2014-2015 austral-summer seasons. 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.

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 â€" but this situation is about to change.

“Populations of predatory king crabs are already living in deeper water,” Aronson said. “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 degree Celsius in the last 50 years, making it one of the fastest-warming ocean regions.

“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.”

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Filed under: biodiversity, climate and weather, endangered species, Environment, global warming Tagged: | Antarctica, biodiversity, climate change, global warming, invasive species