Little Creatures of the Deep [Slide Show]

A new robot successfully traps the larvae of exotic species living in the extremely deep ocean

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The larvae of some nectochaetes have more elaborate setae. In this case, the larva was rolling up into a ball with setae pointing outward, perhaps for protection from perceived predators.

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At more than 7,000 feet (2,150 meters) down in the ocean, the water pressure is a crushing 3,150 pounds per square inch. Oceanographers who have tried to snag samples of life in these pitch black, frigid, have had to suck in water at high speed and try to filter out organisms, often damaging them in the process. But a team led by the Woods Hole Oceanographic Institute last week snatched up the intact larvae of 16 different animals.

The team used a new sampler, called SyPRID, which was carried to the great depths by an autonomous underwater . For more than eight hours engineers steered the robot in a precise and slow pattern, itself an achievement, which barely disturbed the water in front of the craft, a common complication that pushes the tiny larvae out of a vehicle’s path before an instrument can pull them in. The long, cylindrical sampler processed large volumes of water every hour, yet did it slowly enough to not harm the fragile creatures, which are only a few hundred microns across. The final trick, according to an email from Carl Kaiser, the vehicle program manager at Woods Hole, “is getting most of the larvae down to a relatively still area where they are further protected from the moving water.”

Scientists are eager to have intact specimens of common and rare organisms from the very deep ocean, especially in the early larval stages of life, because the samples can explain a lot about marine food webs, the changing nature of ocean ecosystems and how methane seeping up from the seafloor may be affecting the chemistry of the sea. Two images of Sentry and SyPRID, and nine images of the beautiful larvae, can be seen in the accompanying slide show (see link below). Captions are based on descriptions by Laurel Hiebert, a team member at the University of Oregon.

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