Global warming led to the colonization of Antarctica by crabs

On the edge of Antarctica, royal crabs were found - crustaceans of the same species as red Kamchatka crabs. Scientists suggest that animals have landed in Antarctic waters as a result of warming in the region.

Their numerous populations are found on the southern side of the Antarctic Peninsula - in a depression formed in the continental shelf, scientists report in the journal Proceedings B.

As the authors of the material suggest, crabs came to the Antarctic with warm currents.

Considering that crabs tend to eat other inhabitants of the seabed, with their appearance the ecosystem of Antarctica can significantly change, warn researchers. In search of life

In March last year, researchers sent to the Earth of Palmer underwater vehicle Genesis, controlled remotely from the University of Ghent in Belgium.

A group of scientists planned to inspect the area for living organisms living there. Specifically, the team did not look for crabs and was extremely surprised to discover such a large number of large specimens.

According to scientists, in the hollow there can be about 1.5 million individuals of the royal crab.

In the extracted female, the researchers found mature eggs and larvae.

Royal Crabs

Crabs could have lived in the Antarctic for 30-40 years

"According to our assumptions, there was an incident - and perhaps more than once - when the shelf was covered with a stream of warm water, along with which the larvae of crabs entered the hollow," said the head of the research team, Professor Craig Smith of the University of Hawaii.

It is believed that the royal crabs can not live at a temperature below + 1.4 C.

The temperature of the sea in the region of Antarctica is deeper in the deep water than near the coast, and crabs were found only at a depth of 850 meters.

According to scientists, the crustaceans settled there no earlier than 30-40 years ago. Before that, the water for them was too cold even at the very bottom of the hollow.

While crabs can not survive on the continental shelf, which is at a depth of 500 meters, but this can change.

"Given the speed at which the sea warms, the water temperature at the level of the continental shelf will jump over the mark of + 1.4 C for 20 years, and then the crabs are likely to live in shallow water," said the BBC professor Smith.

Predators

A mark of 850 meters, above which crabs are not chosen, is also the boundary separating the saturated shallow-water ecosystem from the very limited in composition and number of inhabitants of the marine depths.

"Above the" zone of crabs, "the animal and vegetable world turned out to be more diverse and abundant - with echinoderms, including snakeheads, sea lilies and sea cucumbers," says Professor Smith.

"In the crab zone itself, we did not find anything like this, as well as 50-100 meters above it, so we believe that the crabs are making outings in shallow water to feed themselves.We assume that some of these organisms will eventually die out for crabs, "the scientist added.

Previously, scientists have already suggested that the royal crabs at some point will settle in the Antarctic region, where they will bring warm currents from South America.

The distance between the ends of the claws at the royal crabs is almost a meter. They are considered one of the main predators of the seabed.

There are about 120 species of these crustaceans, and the most common of them - the red king crab has already affected the ecology of Norwegian waters, where it came from Russia. At the same time, in the northern latitudes the Kamchatka crab became an important object of fishing.

In the Antarctic waters catching royal crabs will not be permitted, although this way one could control the population size if its impact on the ecosystem is too negative, says Professor Smith.

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