Secrets of the Abyss

A survey of the bottom of the ocean is revealing new life and diverse ecosystems.

It was long thought that the deep ocean was a desert wasteland devoid of life. But prodding its icy depths with remotely operated vehicles that can withstand the bone-crushing pressures and extreme cold, scientists are illuminating a deep sea teeming with strange and surprising creatures.

Now, a team of scientists from Germany, Russia, and Spain has hit bottom to survey the organisms that live in or on the seafloor. Towing a sledge tethered by a 10,000-meter-long cable behind their research vessel "Meteor," they combed a 700 km transect of the Abyssal Plain 5,000 meters deep in the southern Atlantic's Angola Basin.The team discovered rich communities of organisms from microscopic Loricifera, invertebrates that live in the spaces between marine gravel, to rare "macrofauna" that may shed light on life in extreme environments.

Epibenthic sledge and a deep-sea octopus. Samples were collected with different gears to get all size-classes of benthic organisms. A cable of 8 km length is needed to send the epibenthic sledge to the bottom of the sea at 5000 m depth. It takes up to 8 hours to get a single sample.

The project, called Latitudinal Gradients in the Deep Sea of the Atlantic Ocean, or DIVA, discovered many animals new to science including 90 percent of the copepods they uncovered and more than 20 new Cumacea, small, often spiny crustaceans with long, thin, forked tails.

The team hopes to use this information to get a clearer picture of the diversity of ocean bottom ecosystems and better understand their composition. Preliminary results indicate that the seafloor varies greatly between locations, with different organisms dominating different sites.

The DIVA team, made up of more than 40 international specialists, is cooperating to identify deep-sea organisms of all taxonomic groups, from bacteria to the large macrofauna (sea cucumbers, fishes, crabs).