deep sea as a marine living habitat

7/27/2019 Deep sea as a marine living habitat

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Deep Sea as a

Marine LivingHabitat

R.W.S.L.PriyadarshanaAG/ASF/09/056


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What is Deep Sea?

The deep sea is the largest habitat onearth and is largely unexplored.

That is below the photic zone of the

ocean where sunlight is not penetrate.The oceans are divided into two broad

realms;

1. pelagic

2. benthic


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Pelagic refers to the open water in whichswimming and floating organisms live.

Benthic refers to the bottom sedimentsand other surfaces of the ocean.


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From the shallowest to the deepest,biologists divide the pelagic into 5 as,

1. the epipelagic (less than 200meters, where there can bephotosynthesis)

2. the mesopelagic (200 - 1,000meters, the "twilight" zone with faintsunlight but no photosynthesis)

3.the bathypelagic (1,000 - 4,000meters)

4. the abyssopelagic (4,000 - 6,000meters)

5.the hadopelagic (the deep trenches


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The last three zones have no sunlight atall. That means they are dark.

These zones make up about 75% of theinhabitable ocean space.

Deep-sea is an extremely hostile

environment, with temperatures thatrarely exceed 3C and fall as low as-1.8C" (with the exception of

hydrothermal vent ecosystems that canexceed 350C)

Low oxygen levels, and pressures

between 20 and 1,000 atmospheresbetween 2 and 100 me a ascals .


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Living Organisms in theDeep Sea


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Bathypelagic-ctenophore

Barreleyes

Giant isopod

Black-lip-rattail


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Angler Basket-star

ang tooth-fish Vampire-squid


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Challenges Faced by MarineLife in the Deep Sea

Lack of light

The only available light in the deepestregions of the ocean comes frombioluminescence, which is a chemicalreaction in a creature that produces light.


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Water pressure

Pressure increases 1 atmosphere (atm)

for each 10 m in depth. The deep seavaries in depth from 200 m to about11,000 m, therefore pressure ranges from

20 atm to more than 1,100 atm.

Temperature

With the exception of hydrothermal ventcommunities, where high temperaturesare present, the deep sea is a cold place,with temperatures close to freezing(about 2-4 degrees Celsius, or about 35-


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Overcome Those

Challenges? Lack of LightMost animals have very large eyes with

retinas constructed only of cones, which

increases sensitivity.Many animals have also developed large

feelers to replace peripheral vision.

To be able to reproduce, many of thesefish have evolved to behermaphroditic(an individual in whichreproductive organs of both sexes areresent eliminatin the need to find a


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Water pressure

To cope with the pressure, many fish are

rather small, usually not exceeding 25 cmin length.

Also, scientists have discovered that the

deeper these creatures live, the moregelatinous their flesh and more minimaltheir skeletal structure.

These creatures have also eliminated allexcess cavities that would collapse underthe pressure, such as swim bladders.


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Life appears to cope with pressure effectson biomolecules in two ways.

1. Their membranes and proteins havepressure-resistant structures that work bymechanisms not yet fully understood.

2.Some organisms may use "piezolytes"(from the Greek "piezin" for pressure).

These are small organic moleculesrecently discovered that somehowprevent pressure from distorting largebiomolecules. One of these piezolytes is

trimethylamine oxide (TMAO).


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Temperature


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deep sea as a marine living habitat

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