Deep Sea Trenches

Deep Sea Trenches

Defined: Any long, steep-sided depression in the ocean's floor. They usually occur where one tectonic plate has slid underneath another, forming a crack. Most occur from 7, 300 meters deep to 11000 meters deep.

Trenches lie seaward and parallel to island arcs. The majority of these trenches are found in the Pacific Rim area, and their creation is generally associated with subduction (crust passes under another and sinks into mantle) zones in the ocean crust, resulting in earthquakes.

The Challenger deep is at the deepest point in the Mariana Trench. Only two groups in the world have ever safely reached the bottom. One was the US Navy, and the other was the National Geographic Society in its vessel, the Deepsea Challenger submersible vehicle.

Animals of deep sea trenches generally are adapted to survive in a place that has no sunlight. The food chain works a little bit differently, because energy for producers has to come from sources other than the Sun. Many have large eyes, in an effort to see better. Some others are bioluminescent. Animals have been adapted so withstand pressure and are colored to fit an environment where they cannot be seen.

Some animals of the deep create their own light through bio-luminescence, or self lighting. This self light is caused by a chemical reaction that takes place inside of the fish, creating a resounding glow.

That's all, folks!

The Geology of Ocean Trenches

The Mariana Trench

The deepest trench in the world is the Mariana Trench, which is found in the Pacific Ocean, near the Mariana Islands and the Phillipines. The trench is 1580 miles long, but only about 43 miles wide in most places. At its deepest point, known as the Challenger Deep, the trench is seven miles deep.

The Mariana Trench

The Challenger Deep

Interesting Fact:

Most interestingly, though, is an idea surrounding the trench. The idea is that, because the trench is so deep and so far away from humans, that it could be a possible nuclear waste dump site, because the plate subduction would supposedly push the waste into the Earth's mantle, thus destroying it.

Creatures of the Deep

Bio-luminescence

This is a luminescent shrimp that lives in the depths of trenches. It is food for many of the creatures of the deep. This creatures uses the glowing to confuse predators. This particular shrimp is found in one of the few North American Oceanic trenches.

Coloring

Animals of the deep often are either black, grey, or transparent. Bright colors are not necessary in dark places, chiefly because the animals do not wish to draw attention to themselves.

Fred

Deep Sea Angler Fish

Deep sea anglerfish have adapted to the depths of the ocean by finding an interesting way of catching prey. The fish have a ball of light that hangs from their head used to attract the fish so they can easily cacth them.

Xenophyophores

These are large, unicellular organisms found in deep depths. There are 42 recognized species in a variety of shapes. The best known shape is that of a giant blob of cytoplasm with tons of nuclei within it. They use their excretions to build structures that bulge from the sea floor, .making habitats for other animals, like isopods.

Isopods of the Deep

Isopods are a unique classification of crustaceans that are generally small with multiple legs of generally similar shape and form. Most species are found on the ocean floor, and many of those are located in trenches. They are generally scavengers who eat whatever floats down to them.

An Alternative to the Sun

In the deep, the food chain has to find an alternative energy source, because the Sun cannot penetrate that far. The alternative is found in undersea vents, which release heat from fissures in the Earth's oceanic crust. Animal colonies gather around these vents because they gather energy from them through a process known as chemosynthesis. Usually the communities are mats of bacteria, which become the bottom of the food chain for deep sea animals.

Sources:

http://www.britannica.com/EBchecked/topic/155513/deep-sea-trench

http://www.howitworksdaily.com/environment/deep-sea-trench-life/

http://news.nationalgeographic.com/news/2012/10/pictures/121009-glowing-bioluminescence-oceans-animals/