Antonina Rogacheva / Journal of the Marine Biological Association of the United Kingdom, via Karen Osborn
A species of acorn worm, dubbed Glandiceps abyssicola, that has been rediscovered after not being seen for 140 years.
This is the James Clark Ross, a ship run by the British Antarctic Survey that carried Sue Scott and other researchers on a journey to Tristan da Cunha, a remote island and archipelago in the South Atlantic.
The journey was funded in part by the Pew Charitable Trusts. Over the past decade, Scott has made dozens of dives in the rough water surrounding the island and helped chronicle the unique life there. She's based in northwestern Scotland but finds herself repeatedly drawn to the island — this was her eighth trip — and is one of the few experts on the sea life there. Until now, nobody had seen what lurks just beyond the range of scuba divers, at a depth of about 150 to 300 meters (492 to 984 feet) beneath the ocean's surface.
This is the larvae of a rock lobster (Jasus Tristani) which, at this life stage, is called a puerulus. When it was first found, few of the biologists on board knew what it was.
The seas slugs were collected from the ocean floor near the island of Gough, which is part of the Tristan archipelago.
This little guy was collected by a seafloor trawl near Gough, which is part of the Tristan archipelago. Like all hermit crabs, it uses the shells of other animals in which to live.
These cup corals were found in large numbers in the waters near Tristan da Cunha, at depths between 150 to 300 meters (492 to 984 feet).
The cup corals appear to thrive in the waters beyond the reach of divers, making due with the scant light that penetrates.
This is the island of Tristan da Cunha, with the settlement — known as Edinburgh of the Seven Seas — on the right. On the left is a volcano that erupted in 1961, and the scar from a recent rock fall. The island has a population of about 260 residents.
Recently, islanders built a replica of a traditional Tristan house made of volcanic rock with a roof thatched from New Zealand flax. The house is nestled between lava flows from the island's 1961 eruption.
This larval eel head was photographed by a mid-water trawl, suspended above the seafloor off of Tristan.
In 1873, an unknown species of deep-sea worm was dredged up from the bottom of the ocean. Further analysis showed that the animal, collected from almost 3.5 miles (5.5 kilometers) beneath the surface, turned out to be a new type of acorn worm. It was dubbed Glandiceps abyssicola.
For nearly 140 years, that was the last that humans would see of this type of acorn worm. Acorn worms are a group of animals that live on the seafloor eating pieces of sediment and detritus that float down from above. And the single specimen that was collected in 1873 by the HMS Challenger found its way to Germany, where it was destroyed by bombs in World War II. (Deep-Sea Creepy Crawlies: Images of Acorn Worms)
Then, in 2009, a small chunk of yellow flesh turned up in a sample of sediment collected near the same spot as the original, in the equatorial Atlantic near South America. An anatomical and genetic study of the material, published last month in the Journal of the Marine Biological Association of the United Kingdom, found that it was part of a Glandiceps abyssicola worm's body.
The main reason that the animal hadn't been spotted since 1873 is that it is very fragile, and tends to fall apart when dredged, said Karen Osborn, a study co-author and worm specialist at the Smithsonian's National Museum of Natural History. The dredging sled runs along the seafloor and knocks items into a net with a chain, which isn't exactly a gentle collecting technique, Osborn told LiveScience. Ideally, the animals are collected with submersibles, where they can be delicately plucked from the ocean bottom, she added.
The deep-sea acorn worms are quite different from their shallow-water relatives, which are more muscular, sturdier and easier to sample, Osborn said. The shallow-water variety also tend to dig burrows and siphon particles from the seafloor. This rediscovered species, however, crawls along the ocean bottom, eating particles of detritus.
"They are like little factories for digesting organic matter," Osborn said.
Acorn worms get their name from their proboscis, which resembles the cap of an acorn, Osborn said. Recent studies of which Osborn has been a part have identified more than a dozen new species of acorn worms. The present study was led by Nicholas Holland, a researcher at the Scripps Institution of Oceanography.
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