Deep sea creature

The term Deep Sea Creatures refer to organisms that live below the photic zone of the ocean. These creatures are highly notable for their bizarre looks, generally straying from the look of land based plants and animals and even fish that live in the shallower parts of the ocean. These creatures have to survive in extremely harsh conditions; such as hundreds of atmospheres of pressure, small amounts of oxygen, very little food, no sunlight, and constant, extreme cold. Most creatures have to depend on food floating down from above, which is a very rare occurrence.

Environment

These creatures live in a very harsh environment called the sub-photic zone which is almost completely devoid of light and life, being thousands of feet beneath the surface. The water is very cold (between 3 and 10 degrees Celsius, or 37 and 50 degrees Fahrenheit), and due to the amount of water above this area, there is an enormous amount of pressure (somewhere between 20 and 1,000 atmospheres) and a lack of oxygen.

Characteristics

These creatures that live thousands of feet deep in the ocean would have a hard time surviving. however; they have adapted in order to make life possible. Having been left alone at such deep levels for such a long time, they have been able to adapt to their environments without much interference from outside sources such as humans.

Major Adaptations

Pressure

Due to the extreme pressure of the sub-photic zones, these animals have had to adapt using the process of natural selection in order to survive. The pressure increases by about one atmosphere every ten meters, creating tremendous pressure when going down thousands of meters deep. In order to cope with the pressure, many fish are rather small, usually not exceeding 25 cm in length. Also, scientists have discovered that the deeper these creatures live, the more gelatinous its flesh and the more minimal its skeletal structure. These creatures have also eliminated all excess cavities that would collapse under the pressure, such as swim bladders^[1].

Lack of light

Due to the extreme lack of light, it is hard for these creatures to find food, avoid predators, or even find a mate. To adapt to these conditions, most animals have very large eyes with retinas constructed only of cones in order to increase the light going into the eyes and being processed by the brain. Many animals have also developed large feelers to replace the need for peripheral vision. In order to be able to reproduce, many of these fish have evolved to be hermaphroditic, eliminating the need to find a mate. Many creatures have also developed very strong senses of smell in order to detect the chemicals released by mates.

Lack of Resources

At this depth, there is not enough light for photosynthesis to occur and not enough oxygen to support a fish living at higher levels. In order to survive, these creatures have much slower metabolisms and therefore can survive using little oxygen. They can also go weeks without food. Most food comes from either organic material that falls from above or from eating other creatures that have derived their food through the process of chemosynthesis (the process of changing chemical energy into food energy). Because of the sparse distributions of creatures, there is always at least some oxygen and food. Also, instead of using energy to search for food, these creatures use amazing adaptations which they use to ambush prey.

Deep-Sea Gigantism

The term Deep-sea gigantism describes the effect that living at such depths has on a creature's size, especially relative to the size of relatives that live in different environments. These creatures are generally many times bigger than their smaller counterparts. A good example of this is the Giant Isopod which is, surprisingly, related to the common pill bug. Scientists haven't been able to come up with a reason for this, with the exception of the giant tube worm. Scientists decided that these creatures are so much larger than normal tube worms because they live on hydrothermal vents which expel huge amounts of resources. There is a theory that states that since the creatures in the deep sea don't have to expend any energy on regulating body temperature, and have a smaller need for constant activity, this allows them to alocate more resources to bodily processes. No one is positive though. There are also cases of deep sea creatures being abnormally small, such as the lantern shark, which can fit in the palm of an adults hand, another mystery. ^[2]

Bioluminescence

Smaller cousins of giant tube worms feeding at a hydrothermal vent

Bioluminescence is the ability that some creatures have to create light through chemical reactions inside their bodies. Bioluminescence can be used in many ways. It can be used to light a creature's way, to attract prey, or even a mate. Many animals in the deep sea, and ocean in general, are bioluminescent. Ranging from the Viper fish to the Flashlight fish, actually named for the light it gives off^[3]. Some creatures, such as the angler fish have a concentration of photophores in a small limb protruding from their bodies which is used as a lure. This allows it to catch dangerously curious fish, which is much like angling, hence its name. Bioluminescence can also be used to confuse enemies. The chemical process of bioluminescence requires at least two chemicals: the light producing chemical called luciferin and the reaction causing chemical called luciferase.^[4] The luciferase catalyzes the oxidation of the luciferin causing light and resulting in an inactive oxyluciferin. Fresh luciferin must be brought in through the diet or through internal synthesis.^[4]

Chemosynthesis

Since at such deep levels, there is little to no sunlight, photosynthesis is impossible as a means of energy production, leaving some creatures with the quandary of how to produce food for themselves. For the giant tube worm, this answer comes in the form of bacteria that live inside of it. These bacteria are capable of chemosynthesis and live inside of the giant tube worm which lives situated on hydrothermal vents. These vents spew very high amounts of chemicals that these bacteria can transform into energy. These bacteria can also grow freely of a host and create mats of bacteria on the sea floor around the hydrothermal vent which creatures can eat, providing energy for the food chain. This source of energy creates large occupations of animals in areas where there are hydrothermal vents, allowing scientists an easy stop for research. ^[5]

Deep Sea Research

In the past few years we have realized how little we truly know about the ocean ^{[citation needed]}. Less than 2% of the ocean floor has been explored and dozens of new species of deep sea creatures are being discovered with every dive. The submarine used to patrol the deep seas is called the DSV Alvin which is owned by the US Navy and is operated by the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Massachusetts. This 16 ton submarine is used to explore the deep sea since it can stand up to the terrible pressure and is still maneuverable, despite its weight and size. However, studying deep sea creatures is problematic, since with the extreme change in pressure, and environment in general, these creatures can't survive for very long, if at all, on the surface. This makes in depth research very hard because so much of what we want to know about only occurs while the creature is alive. There have been recent developments that allow scientists a closer look at these creatures for a longer time. A marine biologist, Jeffery Drazen, has been studying this problem, and has come up with a possible solution, a pressurized fish trap. The idea is to capture one of these creatures, and adjust the trap's pressure levels to those of the area, and, while bringing it up, slowly change the pressure levels to normal surface levels, with the hopes that the creature will be able to adjust. ^[6]