The vast reaches of the ocean are still unexplored — and they remain one of the most challenging terrains on the planet. But scientists from Oceanlab at the University of Aberdeen, U.K., and researchers from the National Institute of Water and Atmospheric Research in New Zealand teamed up to provide us with a glimpse into life in the deepest parts of the sea. Focusing on the New Hebrides trench in the Pacific, a trench that reaches 23,000 feet deep, the scientists discovered that creatures living at these depths are full of surprises, revealing an ecology that is not typical of other trenches. 

"The footage captured by the team during the 30-day voyage at the end of 2013 shows large, grey cusk eels, some 1-meter long, chomping on the bait that had been attached to the lander. The fish mingle with large, bright red prawns scrabbling around on the sandy seabed... However, the team noted marked differences when they compared this trench with others they have studied, which include the Japan trench, the Izu-Bonin trench and the Kermadec among others," BBC reports.

The difference is that one of the most common deep sea fish found in these trenches, the grenadier, was entirely absent. Instead, there was a high number of cusk eels, which are usually in very low numbers in the other trenches.

The reason, the researchers believe, is the difference in the nutrients found in the waters above the trenches. More food above means more grenadiers below, but cusk eels are able to survive in low food environments. The finding may mean that these species are more widespread than previously thought.

The footage was collected with specially designed ultra-deep sea cameras and traps, which were deployed 27 times at varying depths in the trench. This expedition was part of The Hadal Environmental and Education Partnership, or Hadeep, which uses the remotely operated equipment to gather information about life at these extreme depths and sheds light on what is happening far from the more familiar waters at the ocean's surface. 

The new information gleaned from this expedition will help improve the scientific community's understanding of what is happening now, and how future changes in the ocean's systems due to climate change and other factors is affecting life throughout the ocean's depths.

"Should the current system change, it is highly likely to have significant cascading effects on the deep sea community. The deep sea is potentially a kind of silent victim in the era of a changing climate," said Dr Alan Jamieson of Oceanlab.

"Should the current system change, it is highly likely to have significant cascading effects on the deep sea community. The deep sea is potentially a kind of silent victim in the era of a changing climate."

Read more at: http://phys.org/news/2014-03-rarely-animals-hebrides-trench.html#jCp

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