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March Of The King Crabs

By Kieran Ball - 12 Apr 2011 13:9:0 GMT
March Of The King Crabs

Marine scientists are trying to understand why millions of King Crabs are migrating from the ocean floor onto the continental shelf of Antarctica.

The worry is that the invasion of the shell crushing crabs could have a disastrous effect on Antarctica's ecosystem. King Crabs haven't inhabited the area in some 40 million years and many of the region's molluscs, such as clams, brittle stars and snails have evolved softer shells, which offer no defence to the crabs' strong claws and teeth.

The crab migration was discovered as a result of ongoing research into several Antarctica organisms that could be used to fight human diseases, such as cancer and flu. James McClintock from The University of Alabama at Birmingham (UAB) has shown that sea squirts, for example, produce substances that combat skin cancer and he's worried that the invasion of the predator crabs could wipe out some species indigenous to the area.

''I am concerned that species could disappear,' he said, ''And we could lose a cure to a disease.''

It was Sven Thatje, a colleague of McClintock from the University of Southampton in England who first discovered the crabs back in 2007. Further studies have now revealed more crabs than ever moving closer to the Antarctica coast. What's more, the crabs are breeding and thriving in this food rich environment.

Fishermen are eager to step in to scoop up the problem, so to speak, however, this brings environmental issues of its own and fishing in these icy waters is extremely dangerous due to logistics and weather conditions.

Climate change is almost certainly the reason behind the migration. Air temperatures in the region have risen 11 degrees Fahrenheit since 1950, making the water just habitable for the creatures. Previously, the crabs are unable to remove magnesium from their blood, as the water was too cold for the physiological mechanism to function. Which begs the question, as sea temperatures rise, is the lifting of this 'magnesium barrier' causing the same phenomenon to happen at the other end of the planet too.

McClintock says: 'This is just one example of a species expanding its range into a new territory. There will certainly be more as the climate warms up.'