Cold seeps, hydrothermal vents and seamounts

Understanding some of the habitats that have the most peculiar ecosystems is key in understanding how life has evolved in the deep sea.  One such habitat that creates high biodiversity in the deep sea are cold seeps.

Cold seeps can be found in all oceans and usually occur in cracks and fissures around the edges of the oceanic plate. These cold seeps release compounds such as methane and hydrogen sulfide into the water column. These cold seeps unexpectedly provide nutrients for single celled microbes such as bacteria, that then thrive and create a more complex ecosystem around the seeps.

Colony of Lamellibrachia luymesi around a cold seep in the Gulf of Mexico.
Fig. 1. Aggregation of Lamellibrachia luymesi around a cold seep in the Gulf of Mexico. (Image free to use & share)

Tube worms are the most documented benthic organisms found at this sites as illustrated in the image but crabs and new species of shrimp have been discovered.

Another deep sea habitat are hydrothermal vents. This habitat is another type of extreme environment presenting conditions that would usually inhibit life.

Hydrothermal vent
Fig. 2. A Smoking hydrothermal vent in the Endeavour hydrothermal field off the Canadian coast. (image free to use & share)

The vents heat the sea water surrounding the openings and create a temperature rise in the close to freezing deep sea water. The heat comes from tectonic activity below the vents. Water that has seeped into the cracks in the plates is forced back up by pressure and along the way it collects minerals and chemicals from the surrounding rocks. These minerals are utilised by organisms to create energy for themselves. Hydrothermal vents, like cold seeps, are found all over the world from depths as shallow as 20 metres to deep oceanic trenches such as the marina trench. The organisms found are similar to that of of cold seeps with extraordinarily large tube worms being the dominant species.

The last deep sea habitat that i will discuss in this blog are seamounts. Seamounts are typically a mountain that has rose from the seafloor, again formed from tectonic activity that created an underwater volcano. These extinct volcanoes have peaks that are often found thousands of metres below the surface and are found all over the globe. Seamounts are the most known of deep sea habitats because of the frequency of how many have been discovered. They are equally as important as cold seeps and hydrothermal vents in creating a complex ecosystem upon which many different ocean food chains rely upon.

Patton_Seamount
Fig. 3. Multibeam echosound (sonar) of Patton Seamount. (Image free to use & share)

The goblin shark has been captured at these locations more frequent than any other deep sea habitat suggesting that seamounts are of key importance to this rare species(Kukuyev 1982).

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