Thursday, December 25, 2014

World’s deepest fish found dwelling in the Mariana Trench

Scientists from the University of Aberdeen have discovered the world’s deepest fish dwelling in the Mariana Trench. The fish is among other new species caught on video as part of a deep sea expedition to provide a detailed analysis of the trench.

The Mariana Trench is the deepest part of the world’s oceans, with a maximum-known depth of 10,994 meters. The trench is part of the hadal zone, which describes the deepest marine habitats on the planet. To date there are 21 such trenches with depths that range from 6,000 to 11,000 meters, (or 3.7 to 6.8 miles). The new species discovered this month add to over 400 known species that are able to survive at these depths.

The latest expedition, a 30-day Hadal Ecosystem Study (HADES), was achieved with the UK’s deepest diving vehicle, the Hadal Lander. An international team of scientists conducted the analysis while aboard Falkor,  Schmidt Ocean Institute’s Research Vessel. The team covered the entire depth range of the trench, sampling between 5,000 and 10,600 meters.

The fish receiving extra attention is a certain type of snailfish and was observed at 8,145 meters deep making it the greatest depth a fish has been found. Not only is it now the deepest fish known, its unique appearance adds some mystique.

“This really deep fish did not look like anything we had seen before, nor does it look like anything we know of”, said Dr Alan Jamieson from the University of Aberdeen, in a statement. “[I]t is unbelievably fragile, with large wing-like fins and a head resembling a cartoon dog”.

The footage of the snailfish adds to the numerous discoveries made. Footage of a ‘superigant’ amphipod was also recorded, representing the first time the species was filmed alive. The giant amphipod was first recovered in traps off New Zealand in 2012.

Researchers exploring the hadal zone hope to collect as many species as possible and to characterize the unique ecosystem. Trench subduction zones are also the sites of earthquakes that sometimes result in tsunamis, so further analysis of this region could shed light on factors which contribute to these events. Researchers are also hopeful that specimens collected in the hadal zone can lead to the discovery of therapeutic agents.

Marine life capable of living in the hadal zone has had to evolve to survive the extreme pressure and temperature. Scientists are particularly interested in compounds that help protect proteins from folding improperly under these conditions.

One of these molecules, a molecule called trimethylamine N-oxide (TMAO), has already been discovered. Researchers have previously found that TMAO increases with depth in bony fish. This molecule is also being investigated for its potential to treat Alzheimer’s disease.

Though the team has collected over 100 hours of footage, their work has just begun, and they expect the samples they returned with to keep them busy for a while.

“We have tons of animal samples, mud samples, rock samples, and water samples and when we get back from the holidays, all of us are going to start analyzing those,” said Jeff Drazen of the University of Hawaii,  the co-chief scientist on the research cruise. “Hopefully we’ll have many more discoveries in the next year or two.”


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