The seabed surrounding the Antarctic Peninsula, is threatened by the insatiable hermit crab.
The attacker — a bright red deep predator — marching in step with the global warming.
Systematics highlighted this crustacean just five years ago, setting as Neolithodes yaldwyni and placing among the 120 other species of Lithodidae. Scientists call it the ecosystem engineer as crab burrows into the seabed, feeding on worms and other small animals. This activity (under certain population size) has enormous implications for the entire marine food chain.
Laura Grange of the University of Hawaii (USA) and her colleagues studied the Palmer Basin — the area of the Weddell Sea, 120 kilometers from the border of the continental shelf. On a plot of more than two kilometers underwater camera spotted four dozen crabs at depths below 850 m, that is where the water is relatively warm for this region — 1,4? C.
Extrapolate to the entire cavity (14 km long and 8 km wide), the researchers evaluated the crab population of 1.5 million individuals. The same density is in place of crab fishing in Alaska and around the island of South Georgia in the British South Atlantic.
As indicated by the camera, crabs (carapace in diameter — 10 cm) pull out the 20-centimeter hole in the soft bottom. Seen pregnant females: Play is under way.
Once the coastal shelf waters warm up, crustaceans crawl out of depression at a depth of 400 to 600 m and continue the march. While the waters surrounding the Antarctic Peninsula are warming by an average of 0,1? C per decade.
Hermit crabs are not new to the Antarctic. Crabs inhabit shallow waters of the Antarctic Peninsula, at least 14 million years.