What is the source of energy for the inhibitants living very deep inside the ocean i.e. more than 500m deep , as sunlight doesn't reach there ?
A deep sea community is any community of organisms associated by a shared habitat in the deep sea. Deep sea communities remain largely unexplored, due to the technological and logistical challenges and expense involved in visiting this remote biome. Because of the unique challenges (particularly the high barometric pressure, extremes of temperature and absence of light), it was long believed that little life existed in this hostile environment. Since the 19th century however, research has demonstrated that significant biodiversity exists in the deep sea.
The three main sources of energy and nutrients for deep sea communities are marine snow, whale falls, and chemosynthesis at hydrothermal vents and cold seeps.
Marine snow
The upper photic zone of the ocean is filled with particle organic matter (POM) and is quite productive, especially in the coastal areas and the upwelling areas. However, most POM is small and light. It may take hundreds, or even thousands of years for these particles to settle through the water column into the deep ocean. This time delay is long enough for the particles to be remineralized and taken up by organisms in the food webs.
Scientists at Woods Hole Oceanographic Institution conducted an experiment three decades ago in deep Sargasso Sea looking at the rate of sinking.[28] They found what became known as marine snow in which the POM are repackaged into much larger particles which sink at much greater speed, 'falling like snow'.
Because of the sparsity of food, the organisms living on and in the bottom are generally opportunistic. They have special adaptations for this extreme environment: rapid growth, effect larval dispersal mechanism and the ability to use a ‘transient’ food resource. One typical example is wood-boring bivalves, which bore into wood and other plant remains and are fed on the organic matter from the remains.
Whale falls
For the deep-sea ecosystem, the death of a whale is the most important event. A dead whale can bring hundreds of tons of organic matter to the bottom. Whale fall community progresses through three stages
Mobile scavenger stage: Big and mobile deep-sea animals arrive at the site almost immediately after whales fall on the bottom. Amphipods, crabs, sleeper sharks and hagfish are all scavengers.
Opportunistic stage: Organisms arrive which colonize the bones and surrounding sediments that have been contaminated with organic matter from the carcass and any other tissue left by the scavengers. One genus is Osedax.,[30] a tube worm. The larva is born without sex. The surrounding environment determines the sex of the larva. When a larva settles on a whale bone, it turns into a female; when a larva settles on or in a female, it turns into a dwarf male. One female Osedax can carry more than 200 of these male individuals in its oviduct.
Sulfophilic stage: Further decomposition of bones and seawater sulfate reduction happen at this stage. Bacteria create a sulphide-rich environment analogous to hydrothermal vents. Polynoids, bivalves, gastropods and other sulphur-loving creatures move in.
hydrothermal vent
Hydrothermal vents were discovered in 1977 by scientists from Scripps Institution of Oceanography. So far, the discovered hydrothermal vents are all located at the boundaries of plates: East Pacific, California, Mid-Atlantic ridge, China and Japan.
New ocean basin material is being made in regions such as the Mid-Atlantic ridge as tectonic plates pull away from each other. The rate of spreading of plates is 1–5 cm/yr. Cold sea water circulates down through cracks between two plates and heats up as it passes through hot rock. Minerals and sulfides are dissolved into the water during the interaction with rock. Eventually, the hot solutions emanate from an active sub-seafloor rift, creating a hydrothermal vent.
Chemosynthesis of bacteria provide the energy and organic matter for the whole food web in vent ecosystems. Giant tube worms can grow to 2.4 m (7 ft 10 in) tall because of the richness of nutrients. Over 300 new species have been discovered at hydrothermal vents.[31]
Hydrothermal vents are entire ecosystems independent from sunlight, and may be the first evidence that the earth can support life without the sun.
Cold seeps
A cold seep (sometimes called a cold vent) is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs, often in the form of a brine pool
A deep sea community is any community of organisms associated by a shared habitat in the deep sea. Deep sea communities remain largely unexplored, due to the technological and logistical challenges and expense involved in visiting this remote biome. Because of the unique challenges (particularly the high barometric pressure, extremes of temperature and absence of light), it was long believed that little life existed in this hostile environment. Since the 19th century however, research has demonstrated that significant biodiversity exists in the deep sea.
The three main sources of energy and nutrients for deep sea communities are marine snow, whale falls, and chemosynthesis at hydrothermal vents and cold seeps.
Marine snow
The upper photic zone of the ocean is filled with particle organic matter (POM) and is quite productive, especially in the coastal areas and the upwelling areas. However, most POM is small and light. It may take hundreds, or even thousands of years for these particles to settle through the water column into the deep ocean. This time delay is long enough for the particles to be remineralized and taken up by organisms in the food webs.
Scientists at Woods Hole Oceanographic Institution conducted an experiment three decades ago in deep Sargasso Sea looking at the rate of sinking.[28] They found what became known as marine snow in which the POM are repackaged into much larger particles which sink at much greater speed, 'falling like snow'.
Because of the sparsity of food, the organisms living on and in the bottom are generally opportunistic. They have special adaptations for this extreme environment: rapid growth, effect larval dispersal mechanism and the ability to use a ‘transient’ food resource. One typical example is wood-boring bivalves, which bore into wood and other plant remains and are fed on the organic matter from the remains.
Whale falls
For the deep-sea ecosystem, the death of a whale is the most important event. A dead whale can bring hundreds of tons of organic matter to the bottom. Whale fall community progresses through three stages
Mobile scavenger stage: Big and mobile deep-sea animals arrive at the site almost immediately after whales fall on the bottom. Amphipods, crabs, sleeper sharks and hagfish are all scavengers.
Opportunistic stage: Organisms arrive which colonize the bones and surrounding sediments that have been contaminated with organic matter from the carcass and any other tissue left by the scavengers. One genus is Osedax.,[30] a tube worm. The larva is born without sex. The surrounding environment determines the sex of the larva. When a larva settles on a whale bone, it turns into a female; when a larva settles on or in a female, it turns into a dwarf male. One female Osedax can carry more than 200 of these male individuals in its oviduct.
Sulfophilic stage: Further decomposition of bones and seawater sulfate reduction happen at this stage. Bacteria create a sulphide-rich environment analogous to hydrothermal vents. Polynoids, bivalves, gastropods and other sulphur-loving creatures move in.
hydrothermal vent
Hydrothermal vents were discovered in 1977 by scientists from Scripps Institution of Oceanography. So far, the discovered hydrothermal vents are all located at the boundaries of plates: East Pacific, California, Mid-Atlantic ridge, China and Japan.
New ocean basin material is being made in regions such as the Mid-Atlantic ridge as tectonic plates pull away from each other. The rate of spreading of plates is 1–5 cm/yr. Cold sea water circulates down through cracks between two plates and heats up as it passes through hot rock. Minerals and sulfides are dissolved into the water during the interaction with rock. Eventually, the hot solutions emanate from an active sub-seafloor rift, creating a hydrothermal vent.
Chemosynthesis of bacteria provide the energy and organic matter for the whole food web in vent ecosystems. Giant tube worms can grow to 2.4 m (7 ft 10 in) tall because of the richness of nutrients. Over 300 new species have been discovered at hydrothermal vents.[31]
Hydrothermal vents are entire ecosystems independent from sunlight, and may be the first evidence that the earth can support life without the sun.
Cold seeps
A cold seep (sometimes called a cold vent) is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs, often in the form of a brine pool
