AAAS, Boston –
A host of unwelcome visitors could invade the Antarctic seafloor within the next ten to fifteen years, as ocean temperatures rise with global warming, said researchers today at the AAAS meeting here in Boston.
The scientists expect King crabs to be the first invaders, with sharks to follow.
The communities under threat from these invasions are extremely unique and highly diverse, with weird and wonderful inhabitants such as ribbon worms, sea spiders, and the aptly-named brittle stars, which break apart at the slightest touch, but can fortuitously regrow their limbs.
For hundreds of millions of years, these ancient communities have enjoyed a relatively safe haven in Antarctic waters, which are free of modern predators with crushing mouthparts such as crabs and sharks.
But a rise in sea temperature of a few degrees could change this, said marine biologist Richard Aronson of Dauphin Island Sea Lab.
At very low temperatures and high pressures, the concentration of magnesium in crab’s blood becomes toxic. As sea temperatures increase, crabs will be able to extend their range into areas that they are no longer off limits due to this physiological obstacle.
Similarly, sharks have a chemical called triethylamine oxide (TMAO), which is needed to counterbalance the build up of urea generated by their continuous movement. But TMAO is needed in greater doses at lower temperatures and so there appears to be a thermal cut off point of how much they produce.
The Antarctic has previously marked that cut off point, but the researchers highlighted that this is one of the fastest warming regions of the planet. It’s currently warming at a rate of approximately 1 degree Celsius each 25 years.
Cheryl Wilga, associate professor of physiology at the University of Rhode Island, described the Antarctica biodiversity as a “smorgasbord” for invading predators.
“There will be winners and losers”, said Aronson, who predicts that brittlestars will be “hammered” by the invasion, but that brachiopods, commonly known as lampshells, will probably hold up fairly well.