You might not get to see an eruption very often but we live on a volcanic planet, where they happen all the time. Most volcanic activities happen not on land but under water in the deep ocean covering 2/3rds of the earth surface. Those eruptions give arise to one of the strangest ecosystems on Earth lies deep under the ocean, which are called hydrothermal vents.
While an underwater volcanic eruption is going on water seeps through cracks in the Earth’s crust, dissolving metals and minerals as it becomes super-heated from nearby magma. This water, which can reach temperatures of 400°C – eventually rises back through the ocean floor, erupting as a geyser from a hydrothermal vent. The dissolved minerals and metals precipitate on contact with the cold sea water, forming a chimney around the vent.
When the high-heated water comes out from the vent opening it mixes with the near freezy sea water, as minerals get precipitated to form particles they form roughly cylindrical chimney structures. With time these stacks precipitation give rise to huge chimney structures which sometimes may reach the height of 60 meters. An example of such a towering vent was “Godzilla”, a structure in the Pacific Ocean near Oregon that rose to 40 m before it fell over.
Oases of life
Tons of sulphids, sulpher bearing minerals and ions like barium, calcium, and silicon are solidifying in to towering chimneys as high as a three story house. At 400 C, This cocktail of chemicals would be lethally toxic to most forms of life. But amazingly a particular kind of bacteria thrives here. And feeding on the bacteria, vast numbers of shrimps swims around. So, beyond the far that reach the suns power a rich independent community exists consuming energy directly from the earth’s molten core.
Hydrothermal vents are home to dozens of un-described species. Huge red-tipped tube worms, ghostly fish, strange shrimps with eyes on their backs and other unique species thrive in these extreme deep ocean ecosystems found near undersea volcanic chains. Life driven here by a process called chemosynthesis; specialized bacteria create energy from the hydrogen sulfide present in the mineral-rich water pouring out of the vents. These bacteria from the bottom level of the food chain in these ecosystems, upon which all other vent animals are dependent.
At a glance, the animals inhabiting deep-sea hydrothermal vents seem so similar to other deep-sea creatures. But in fact, they are unlike any other form of life on Earth. After the first discovery of hydrothermal vents in 1970s, more than 300 species have so far been identified in deep-sea hydrothermal vent ecosystems, of which over 95 percent are new species. Vent dwelling communities of shrimp, crabs, giant tubeworms, clams, slugs, anemones and octopuses are unique to itself.
Vent clams and Blind crabs pay the top level predatory role in the vent food web, which is initiated by chemosynthetic bacteria. In addition to the extreme pressure, low temperatures, and lack of light that characterize the deep sea in general, a variety of other factors that are hostile to most animals prevail in these environments. Hydrothermal vent regions show extremes in temperature, areas of very low oxygen, and the presence of toxic hydrogen sulfide and heavy metals.
It is really strange how these animals are adapted to those extreme conditions. Scientists are still studying on their physiological and behavioral adaptations. For an example, The Pompeii worm is adapted to the high temperatures and pressures of the hydrothermal vents by using a thick layer of bacteria to protect it from heat and by hiding inside a papery tube to protect it from predators.