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The Abyssal Zone is one of the many benthic zones we have highlighted to describe the deep oceans. This particular zone is found at depths of 2,000 to 6,000 meters (6,560 to 19,680 feet) and stays in perpetual darkness.

oceanic marine regions

Just below the abyssal zone and extending to the bottoms of the deepest trenches is the hadal zone. Very few animals exist in this habitat. Just above the abyssal zone is the bathyal zone and just above that the photic zone where much of the oceans life exists.

Because water pressure increases one atmosphere every 33 feet in depth, animals in the abyssal zone must be able to withstand tremendous amounts of pressure. This pressure makes it very difficult for humans to explore the deep ocean. For example, the deep Marianas trench off of the Philipeans is almost completely unexplored. The only submersable that has made these depths is the French bathyscaph Trieste.

Creatures: Animals
Animals in the deep ocean are unique. Because food is scarce in this zone most animals have large gaps to injest any possible food. A great example of this is the deep-sea anglerfish. In many ways the deep sea is about eat or be eaten.

Other deep sea animals include the infamous giant squid, black swallower, tripod fish.

Deep Sea vents: Chemosynthesis, the basis of life in the deep sea
A remarkable find when submersables starting probing the deep sea was the presence of extraordinary abundance of life around mid-ocean vents. Previously, scientists believed that little lived at these emense depths. The only food that would have been avaliable was through dead animals floating down from the surface waters. So what was this abundance sustaining itself on?

The answer came from the discovery that bacteria in the vents were able to convert hydrogen sulfide coming out of the vents into energy. These bacteria then supported large tube worms, crustaceans, and multitudes of other organisms.

The most amazing part of this find was that science had found organisms whose primary energy source was not the sun. It was previously thought that life depended on photosynthesis, converting sunlight to energy. This new find spured questions about how life arose on planet earth. Could it have started through chemosynthesis?

Rob Nelson April 2007

Links to some great Abyssal Zone sites:

Text is temporary. It is used by the crew in the field to prepare video.


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