Hydrothermal Vent Series – Underwater Chimneys

Like a lit fuse running along the surface of the seafloor, hydrothermal vents are frequently found in areas of volcanic activity, such as mid-ocean ridges!

ROPOS is in position for hot fluid sampling at this black smoker vent. Image courtesy of Submarine Ring of Fire 2002, NOAA/OER.

In the depths of the ocean, vents on the seafloor spew out superheated water in clouds of black or sometimes white. The ‘smoke’, or plumes, carry minerals up through the vents and consequently, chimneys begin to grow as the minerals build on each other. Because of the great temperatures, much of the minerals are dissolved in the water and released into the ocean.

With so much volcanic activity on our geologically changing planet it stands to reason we would have the same examples of volcanism in the ocean. Similar to hot springs and geysers on land, hydrothermal vents on the ocean floor are examples how the Earth’s crust is just as volatile below sea level. Often located along areas where tectonic plates are pulling apart, hydrothermal vents have a lifespan of 20-30 years and their chimneys can grow to be as large as 40 metres! A magnificent feat considering their fragility.

Hydrothermal vents attain their water as it seeps through cracks in the seafloor to the rocks, already heated by magma, just under the Earth’s surface. The temperatures at these sites will reach approximately 700° F; 500 degrees more than waters’ boiling point. Explorers have built ROV’s and equipment especially to withstand these temperatures but even then it still gets the best of some.

Courtesy of Wikipedia

In the hostile climate that exists around hydrothermal vents the last thing one would expect to find is life. And yet despite our presumptions, there is a thriving ecosystem on these toxic vents: tube worms, translucent jellyfish, crabs and shrimp, all of phenomenal size. Also in great quantities are mats of bacteria. All of these depend completely on the existence of hydrothermal vents. When a vent ‘dies’, so does its occupants.

In the posts to come I will delve a little deeper into certain aspects of hydrothermal vents, such as the types of creatures in their ecosystem and how they survive, expeditions, and attempts at exploitation. Come back soon to read more!

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