Antarctic Seafloor Exposed After 50 Years of Ice Cover..

Life gets busy wherever it can, even under thick ice cover in Antarctica.

German scientists have inspected an area of seafloor newly exposed by the calving of mega-iceberg A74 and found it to be teeming with animals.

Video cameras tracked abundant filter feeders thriving among the soft muds.

It was a remarkable opportunity for the team as their ship, RV Polarstern, threaded the still narrow gap that exists between A74 and the Brunt Ice Shelf, which produced the giant berg.

• German ship squeezes through narrow ice channel

• Close-up view of crack that made mega-iceberg

• Big iceberg breaks from Antarctica near UK base

Image copyrightOFOBS TEAM/AWI

Image captionA sea pig: These sea cucumbers were particularly abundant on the seafloor

Research groups frequently try to probe waters below freshly calved ice shelves, to better understand how these unique ecosystems operate. But success is not easily won.

Image copyrightOFOBS TEAM/AWI

Image captionA large sea anemone shares a 10cm rock with a number of small, encrusting creatures

You have to be in the right place in Antarctica at just the right time, and often the sea-ice conditions simply won't let a research ship get into position above the target site.

But Polarstern, run by the Alfred Wegener Institute , got lucky. It was already in the eastern Weddell Sea on a pre-planned expedition when city-sized A74 split from the Brunt.

And when the weather calmed last weekend, the ship slipped in behind the berg to take a look at an area of seafloor that is now free of ice cover for the first time in five decades.

Image copyrightOFOBS TEAM/AWI

Image captionA beautiful anemone. The red dots are laser beams spaced 50cm apart to help size objects

Polarstern employs an Ocean Floor Observation and Bathymetry System (OFOBS). This is a sophisticated instrument package that is towed behind the ship at depth.

Over five hours, the system collected almost 1,000 high-resolution images and long sequences of video.

"Despite the years of continuous ice coverage, a developed and diverse seafloor community was observed," said OFOBS team-members Dr Autun Purser and Dr Frank Wenzhoefer.

Video captionNumerous animals were seen attached to small stones scattered across the seafloor

"In the images, numerous sessile animals can be seen attached to various small stones scattered liberally across the soft seafloor.

"The majority of these are filter-feeding organisms, presumably subsisting on fine material transported under the ice over these last decades.

"Some mobile fauna, such as holothurians, ophiuroids, various molluscs, as well as at least five species of fish and two species of octopus were also observed."

Source: BBC News

By Jonathan Amos

Science Correspondent