Life Around Hydrothermal Vents

Life around hydrothermal vents was first discovered in 1977.  Thermal Vents happen when sea water seeps down into cracks and fissures, sometimes as much as two or three miles into the earth’s crust.

hydrothermal vent
hydrothermal vent

As the water comes into contact with the molten magma, the sea water is superheated. The hotter sea water rises to the surface back through the fissures, carrying with it minerals leached from the crustal rock below.

This causes an accumulation of the minerals deposited by the mineral rich water into some geologically unique formations that are called chimneys. One giant chimney discovered in 1991 reached 150 feet high.

The temperature of the water coming out of the vents has been measured at the source. It varies from just 68 degrees to as much as 600 degrees Fahrenheit. The water coming out of the vents doesn’t boil.  This is because of the extreme hydrostatic pressure of all the overlying water.

giant tube worms
giant tube worms

What surprised scientists was that there was an entire ecosystem, a community of diverse life on the bottom of the ocean that thrives on the hydrogen sulfide (H2S) gas released from the vents. Some of the most impressive of the creatures that live here are giant tube-worms. In shallower waters these worms are common, growing to about the size of your hand. But down in the deep ocean these creatures thrive in this really hostile environment, growing to amazing lengths of up to eight feet long.

These tube-worms grow in large clusters around the vents and live inside hard, shell-like protective tubes that attach to the rocks. They live in a symbiotic relationship with a type of bacteria that may hold clues as to how life on earth began billions of years ago. These worms lack mouths, anuses, intestines and stomachs. Their insides are lined with bacteria that oxidize the H2S, turning it into usable nutrients for the worms. The bacteria, in turn, benefit from the relationship because the worms deliver blood-containing hemoglobin, which helps the bacteria to break down the sulfides.

Until the discovery of this bacteria, scientists didn’t believe it was possible for anything to survive in the extreme environment around deep ocean vents. This includes extreme pressure, high temperature and no sunlight. The discovery of the deep-sea thermal vents and the communities of life they support has completely changed the way we define life, perhaps going a long way to explain how life on earth first began.

Click HERE to see a remarkable video showing many of the creatures living among hydrothermal vents.

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