Hydrothermal Vent Series - What about the Heat?

If these are some of the organisms found in the cold, deep ocean, how are they able to withstand the dramatic difference of a hydrothermal vent?

Active “smoker” chimneys precipitating iron, copper and zinc sulfides from 230ÂșC fluid. They are 9 m tall from the base to the top of the chimneys. Dark beehive-type chimneys, here about 30 cm tall, commonly sit on top of these structures. (Courtesy of NOAA, Ocean Explorer)

In the depths of the dark ocean, temperatures reach incredibly freezing degrees and organisms belonging to this habitat have been specifically created to dwell there. But not all areas of the deep ocean are frigid. There are some that reach a different kind of extreme. These fascinating places are called hydrothermal vent sites and at these points along the ocean floor, water becomes beyond boiling! (For more on Hydrothermal Vents, see my previous posts - Underwater Chimneys and Life on the Vents).

Many of those creatures well equipped for freezing waters that we spoke of a second ago frequent the same waters, which causes us to ask the question, how is their bodies both equipped to stand incredibly cold and incredibly hot water at the same time? Do they have a special armor protecting them from feeling any temperature? Well, take a look at the clams, the shrimp, and the octopus-- no such protective barrier exists. And yet, the range of organism variety is just as large as anywhere else in the ocean, if not more so.

To answer our questions, we need to step back and look at the hydrothermal vent site as a whole. A mound of rock pushed up in ridges marks the position of a vent, while the tell-tale signs of mineral-laden chimneys jut from the top. Issuing forth from the openings are clouds of black, or sometimes white, smoke. When the water reaches the magma below it shoots up like a terrestrial geyser many feet above the thriving ecosystem. It quickly mixes with the cold water of its surroundings and, much like the clouds in our atmosphere, begins to spread, thus gradually cooling until it becomes the ambient temperature of deep seawater.

According to an article in Popular Science by Dawn Stover, "the intense heat is limited to a small area...within less than an inch of the vent opening..." (Ocean Planet - Creatures of the Thermal Vents).

So organisms that live on vent sites do not in fact experience the heat from the magma heated water. What they do take part in is the chemicals in which the water consequently abounds, causing them to thrive and flourish. (Read about how these organisms survive the toxic water in my previous article, Life on the Vents).

Pompeii Worm with its protective covering of bacteria. (Courtesy of Wikipedia)

There is at least one exception: the Pompeii Worm, which gets its name from the memorable event involving Mount Vesuvius, is an incredibly designed creature that has the ability to withstand up to 176 degrees fahrenheit, while literally living in the structure of the vents' fragile chimneys.

As always, I hope you have enjoyed this issue of my Hydrothermal Vent series. Next in this series we'll take a look at some of the expeditions that were made to such phenomenal areas in the ocean. Come back soon!

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