Sunday, January 6, 2008
Black Smokers, Giant Tube worms and Hydrothermal vents Oh My!
In 1977 I learned about a special community of organisms within a very strange ecosystem. Found in the waters near the Galapagos Islands, There was no light, the water had a scalding temperatures profile due to nearby hydrothermal sea vents/ volcanic vents. And there were strange creatures that have never been seen before in this once thought inhospitable environment.
Then scientists took an even closer look. These Black Smokers (seen in this picture from a Wikipedia ) are created when superheated water breaks through the Earth's crust and works its way into the water. The superheated water is full of minerals including sulfides which produce these mountainous hills. But that is not all.
There were giant creatures called Tube Worms much larger (up to 8ft long ) then ever seen. What is even stranger is that these huge worms don't have a mouth or a stomach. When small, the bacteria enters their mouth. Over time the mouth and gut disappear. The bacteria then live inside the worms. The red part of the worms are red because of hemoglobin passing through. The whitish part below is like an armor that protects the worm. It can go inside the white armor like substance when in danger.
The bacteria convert the chemicals in the hot water and the worms use it to live and grow. This process is called "chemosynthesis" and is also a symbiotic relationship which means the worms and bacteria help each other for their common good. It works like this:
(1) The insides of the worms are lined with bacteria that oxidize (break down) the H2S (hydrogen sulfide) turning it into usable nutrients for the worms;
(2) The bacteria are helped in this relationship because the worms deliver blood containing hemoglobin ( the chemical that gives our blood the red color).
(3) This helps the bacteria to break down the sulfides which are they absorbed and used by the worms. (Another symbiotic relationship is ants and aphids . The ants care for the aphids and the aphids give off a liquid which the ants collect and eat).
Other creatures like shrimps and crabs live in this dark, deep pressure environment with hot water.
What I did not understand is if the water is scalding and so hot, how could the worms and other creatures survive?
I discovered that deep pressure allows the water to become superhot beyond boiling of water while under the ground. When the water escapes, the less pressurization and extreme cold of the water makes the environment close by more hospitable for the creatures. The farther away from the vent, the cooler the water.
But scientist also began to understand how certain creatures like these tube worms, shrimp, crabs and others actually thrived in the high pressure, the high temperatures. These extremophiles may give us clues how life began on Earth, how might life evolve and still be on Mars, under the ice of Jupiter's moon Europa or other places.
This is only one facet of where extremophiles live. They are in the colored chemical pools in Yellowstone National Park (I will post pictures soon) , in the Antarctic and other places on Earth. Stay tuned.
Students will learn about lifeforms that thrive in inhospitable environments and have a different ecosystems compared to the ones we normally know and underststand.