Deep hydrothermal vents were first found by scientists using cameras, and sonar, back in 1976 along the coast of the Galapagos Islands. One year later, scientists traveled over 2,900 meters below the surface of the ocean using the manned submersible, Alvin, for the first human observations of some newly found structures on the deep sea floor. The Galapagos Rift, between longitude 86 degrees W and 89 degrees W, is an area where the sea floor is formed in a rift valley by continent-sized geologic plates that are slowly moving apart. As the plates move, magma from deep inside the Earth is pushed upward and is met by the pressure of a mile and a half of Pacific Ocean bearing down upon it. This dynamic interchange between the earth and ocean creates an environment of extreme heat, pressure, and geologic, volcanic and chemical activity.
If you can imagine the inside of a super-huge furnace, at the bottom of the ocean, filled with toxic chemicals and the fury of volcanic heat, then you can begin to imagine the environment of hydrothermal vents. This environment is home to strange sea floor formations, bizarre and undocumented forms of life, and where superheated water jets out of the ocean floor bringing with it a soup of microbial life that flourishes in this extreme environment. Scientists were very surprised and excited to find plumes of aqua-colored shimmering water rising from the seafloor.
Scientists had just discovered the first hydrothermal vent. Near vents, water travels down through cracks in the seafloor and is heated by hot, molten rock far below the ocean crust. Temperatures can reach as high as 400degC. As the water heats up, it reacts with the rocks in the ocean crust. These chemical reactions remove all of the oxygen from the water making the water acidic. The hot water rises to the surface of the seafloor and spews out of the vent openings. The pH of this fluid varies from roughly 3 to 5 and temperatures, at their most extreme, can reach over 350 degrees Celsius. This hydrothermal fluid carries with it dissolved metals and other chemicals, like hydrogen sulfide, from deep beneath the ocean floor.
You might think that such a harsh environment would be devoid of life, yet the areas around hydrothermal vents are small 'oases' in the barely populated habitats of the deep sea. Scientists who discovered the first vent system back in 1977 were quite surprised to see this area teeming with a variety of different life forms. The secret was held in the bacteria that were able to harvest energy from the chemical fluid seeping from the vents! These bacteria use sulfur to create food. This process is called chemosynthesis allow organisms to make sugars from chemicals. These bacteria provide the base of the food chain for hydrothermal vent communities.
Since no light is available to organisms living along vent systems, photosynthesis cannot occur. The bacteria are heat loving. Some of the bacteria can survive temperatures over 100 degrees Celsius! Many animals living in vent communities live in a symbiotic relationship with these, sulfide-loving bacteria within their bodies; the bacteria provide sugar to their host while the host provides a safe refuge for the bacteria To learn more about the unusual organisms that live in hydrothermal vents read this fact sheet.
Try this activity to learn how explorers locate vent communities
Learn about organisms that live in vent communities.
No comments:
Post a Comment