Deep sea life

Definition of life

What is life?
The magnitude of the issue does not simply respond as if there is an answer because the issue concerns the both aspect, the philosophical as the chemistry of life. We find that life evolves in time by taking a path defined by an infinite number of parameters, which makes it unpredictable and indefinable.
But there is a biological definition of life:
« an organism is alive when said exchange of matter and energy with its environment by maintaining its autonomy when it replicates and evolves by natural selection. »
All living organisms ensure their stability by responding to changes in their environment.
Life has a tenacious ability to adapt and learn, is not it rather that, the life?

But we also see by observing the galaxies, stars and planets, that matter is able to self-organize without being alive.
However, a good definition of life must take into account this concept, ie, the ability of the material to gradually climb the ladder of complexity.
The tenacity of life is it not proof that it is present everywhere in the Universe, waiting for favorable conditions to continue its path to complexity?

Image: We recognize life when we see it!
The jellyfish Atolla great depths, living in extreme conditions of the abyss, produces light to attract its prey.

The tenacity of life in the deep sea

Even in total darkness of the abyss, life demonstrated great tenacity. Men who venture still farther away, particularly in the abyssal ocean trenches, there unearth amazing bodies. The lowest point of the oceans is the Mariana Trench, located in the north-western Pacific Ocean, 10,916 feet deep. At the end of the 19th century it was thought that life did not exist in the deep lack of light where the pressure conditions are extreme. In the late 20th century, one finds that in seafloor hot springs, a sparse fauna, protected from light, which continues its development by devising forms of life previously unimagined. We discover many microorganisms that promote the growth of the local fauna, crabs, mussels, shrimp and agencies very specific for these environments. It shows the enormous fish, invertebrates, plants and disguised in these strange beings for thousands of years. At 5000 m depth there is between -1 and +5 degrees Celsius and the pressure is 500 times that which exists on the surface of the planet. To resist this environment, beings of the deep tissues are composed of essentially non-deformable liquid and gelatinous, which allows them to balance the external pressure with internal pressure.

Of course it does not permit them to rise to the surface under penalty of exploding. At 1000 meters it is a world without light you encounter, but some organizations have developed bioluminescent organs, mainly to attract their prey. Food, constant concern of living beings is rare in these depths and its agencies must be able to survive long periods of scarcity. Their impressive features of this like fish Diaphus metopoclampa who has a stomach elastic allowing it to swallow prey larger than himself. Their metabolism is also adapted to extreme depths, they live in slow and consume little power.

NB: to 10,000 feet deep, the pressure reaches 1 ton / cm ².

Image: Fish head dragon, idiacanthus atlanticus measuring only a few tens of centimeters, lives at a depth between 2000 and 2800 m. It produces its own light candles through its organs. Credit: The Blue Planet BBC © 2004

The functions of living remains the same

A living being is defined by precisely the features that ensure its survival, nutrition and reproduction remain, even in extreme conditions, an absolute necessity for all living creatures.
As one descends into the abyss and food is scarce.
At 4000 meters, only 3% of the organic matter produced on the surface to the deep reaches.
However, these inhabitants of the depths have adapted to these conditions, such as lantern fish measuring between 10 and 15 cm long and agitated over his head a bright lure.
This light is produced by bacteria that fit inside the body bioluminescent.
This allows small lantern at a time, to attract prey into its gaping mouth, and sexual partners.
Some animals like the sea devil (Caulophryne), adopt a strategy allowing them to save their energy, because they still await the prey come to them.
This predator is bristling with a hundred sensory antennae through which it detects the slightest movement. Sea cucumbers, they aspire seabed sediments to extract the edible particles coming from the surface. The light organs or photophores or bioluminescent, are therefore essential for the survival of the abyssal fauna.

Image: The Caulophryne wide, 50 cm, is still a predator because his sensitive antennae allow him to wait for its prey. It operates more than 1000 m depth where the night is total and temperature, 4 ° C.

Image: The bearded fisherman fish, senses with its white body that is located on the front of the eyes, the chemical compounds released by females.
Credit: The Blue Planet BBC © 2004

Dark adaptation of the Abyss

The peculiar conditions prevailing in deep favored the development of a fauna quite different from that encountered at the surface.
Beyond 100 m in the dark cold water, the plants disappear, life in the deep sea is pure animal.
The animals live in the abyssal areas are surprising:
- Some fish have mouths disproportionate to their size, often with hooks.
- They may have a jaw and a highly expandable stomach that allows them to absorb as large individuals themselves.
- The darkness of the abyss explains the large number of species are blind or, conversely, species with very large eyes, often enlarged and globular da allowing them to capture more light.
- Some have bodies capable of emitting light the candles. The phenomena of bioluminescence are particularly well developed in fish and cephalopods deep.
Fish decoys are on the slopes, on the head or at the end of appendages serving as lamps.

Image: The silver ax (Argyropelecus olfersii) measures just 5 cm, swimming between 150 m and 600 m deep and has large protruding eyes telescopic.

Image: lantern fish measuring between 10 and 15 cm long, waved above his head a snuff it allows both to attract prey into its gaping mouth, and sexual partners.

Image: Squid emit light by the end of their two front tentacles. Their body is covered with candles.

Image: Animal soft, surprising shapes and sizes tailored to operate quietly. Credit: The Blue Planet BBC © 2004

Image: Squid light of the Abyss. For years, the deep, were regarded as deserts.

Image: In the semi-darkness of many animals are transparent. The transparency of this amphipod 12 cm is perfect, his head is composed entirely of two huge eyes which enables it to locate its prey.

Image: This transparent jellyfish is powered by thousands of tiny cilia in this world without obstacle.

Image: The dim light that reaches into the depths request organs adapted as the huge tubular eyes of the body of the abyss.

Mouse sea

Mouse sea type Aphrodita aculeata is a marine worm living in the North Atlantic, the North Sea and the Baltic Sea. The sea mouse is normally buried head first in the sand seabed. It also lives at depths of over 2000 meters. His body is covered with a "dense carpet" of bristles similar to hair, which gave the name "mouse sea" this animal. Its scientific name is derived from Aphrodite, the Greek goddess of love. When you look at his belly, sea mouse resembles a female genital organ. Mouse sea usually measured from 7.5 to 15 inches, but some reach 30 centimeters. They feed on the remains of dead animals or decaying. The bristles lead remarkably light, this is one of its characteristics.
Usually, the bristles have a red glow, scary predators, but when light shines on them perpendicularly, they can take other colors yellow, green and blue.
These colors are considered a defense mechanism, forcing potential predators. But it is possible that this feature does not meet specific biological function because it lives in the dark abyss without light.

It is nevertheless a remarkable example of engineering photonic shows us here nature through this living organism. The sparkling effect is produced by many hexagonal cylinders located inside the bristles. This fine crystalline structure led light with minimal loss. Scientific research is very interested in the sea mouse its effectiveness to transport light through the fibers of silk much more efficient than our optical fibers. The knowledge of nature will enable man to optimize its technology to increase the bandwidth of the optical fiber.

Image: The photonic crystal natural sea Mouse is remarkable for its visual effects. Two Australian researchers, Andrew Parker and David McKenzie showed that the reflectance in the red spines was close to 100%. The diameter of the air holes inside the silk has the same size as the wavelength of red light and the regularity of their positioning enables reflection, the 88 layers of silk wall, to add up.

Dumbo Octopus

The small octopus Dumbo or "octopus ears" gender Grimpoteuthis lives in the depths between 1500 and 5000 meters. When moving it gives the impression of gliding, waving his large ears, which are actually small fins located above the eyes as it uses fins. It is a cephalopod (which means head and feet), called "Dumbo" the name of the flying elephant, animal fictional character created by novelist Helen Aberson in his eponymous book, published in 1939. This rare mollusc is about 25 cm. Cephalopods represent three distinct lineages, squid evolving in the sea, cuttlefish which lives a little above the seabed, while the octopus octopus rarely leaves the bottom. They appeared in the oceans there are hundreds of millions of years, in the Cambrian (Paleozoic Era), well before vertebrates. These initial oceans animals then had an outer shell when the fish and later reptiles have spread some cephalopods in competition with vertebrates, which influenced their evolution, are housed in deep water, losing little just the shell until it disappears in the Tertiary. Abyssal fauna demonstrated great ingenuity to survive and adopt incredible shapes.

Image: Also known as "Dumbo octopus", the Grimpoteuthis is a benthic mollusc i.e. it is on the bottom of the ocean. Dumbo octopuses can reach up to 20 centimeters, are soft-bodied octopus or semi-gelatinous with a pair of fins located above the eyes. Grimpoteuthis swim by waving their fins. They can hover a little above the seafloor looking for snails, worms and other foods.

Giant squid

On board a submersible three places Tsunemi Kubodera, a zoologist at the National Museum of Natural History of Japan, has attracted this giant squid with a bait to be able to shoot. The cephalopod mollusc of the genus Architeuthis, was filmed at 900 meters deep in the Pacific Ocean about 15 km east of the Japanese island of Chichi. This legendary animal fascinates many scientists trying to observe in their natural habitat, the depths of the abyss. Photograph a living giant squid is not an easy task and images of this mollusc are rare.
Specialist Tsunemi Kubodera was photographed a giant squid in 2004 and 2006. It is by using the Disney Channel and NHK Television that the zoologist could see this time with his eyes this rare specimen.
This is following the great whales, their natural predator, the specialists try to film this mysterious animal from the depths.

This giant squid or the colossal squid, eight meters long and silver living in the abyss. It can weigh 500 kg as the female squid caught in the Antarctic in 2007 by New Zealand fishermen. When in danger, it can blow a cloud of black ink or change the color of his skin. It seems that to fertilize a female, it cut the tissue of his partner to deposit his sperm, this method is called « traumatic insemination ».

Image: July 10, 2012, approximately 15 km east of the Japanese island of Chichi, Tsunemi Kubodera, a zoologist at the National Museum of Natural History of Japan spotted a giant squid by 630 meters. This image of the giant squid Architeuthis genus, was filmed between 600 and 900 meters. Credit photo: NHK/NEP/DISCOVERY CHANNEL/AFP

Hydrothermal vents of the deep

Hydrothermal vents are located in all oceans of the world and more specifically in the area of ocean ridges.
Hydrothermal fluids that escape from these vents high temperatures are quickly diluted by the surrounding seawater and some of the minerals they contain precipitate forming hydrothermal edifices.
The largest known hydrothermal building is 40 meters high.
In the abyssal where life is rare, there are hydrothermal vents teeming with species.
These hot hydrothermal vents can reach 350 degrees Celsius.
This hydrothermal fluid is full of microorganisms that nourish a food chain among which there are giant worms 2 m long.
In 1977, geologist John Corliss discovered these pipes, some of which are over 20 meters.
They were dubbed "Hot vents".
At great depths, photosynthesis is absent.
For hydrothermal vent ecosystems, organic matter is produced by bacteria called chemo chemosynthesis synthetics.
They are found on the chimneys of hot springs but also in their black plumes and even in the tissues of some invertebrates places.
These bacteria break down the molecules of hydrogen sulfide released from hydrothermal vents using the oxygen they charge in sea water from this reaction, they draw the energy they use to set carbon and so produce the organic molecules of life.

Image: It is by 3 650 m depth encountered these strange Riftia to 1.80 meters long. They have no gut, mouth and anus and are directly fed by the bacteria they harbor.

Image: Hydrothermal vents are located in all oceans of the world and more specifically in the area of ocean ridges. In a temperature range of 120 ° C to 400 ° C, these sources heat the surrounding cold water from great depths, thus facilitating the emergence of life.