Friday, May 1, 2015
Hydrothermal Vents and Organisms
According to the National Geograpic Website, hydrothermal vents are like geysers, or hot springs, on the ocean floor. These vents are found along the many mid-ocean ridges formed by tectonic plates as the magma rises and cools. As the seawater circulates in the ocean’s crust it becomes super-heated. This superheating creates pressure and as the seawater warms, it begins to dissolve minerals and rise toward the surface of the crust. The hot, mineral-rich waters mix with the cool seawater as they exit the oceanic crust.
Despite the extreme temperatures and pressures, toxic minerals, and lack of sunlight that characterized the deep-sea vent ecosystem, there are many thriving species. Scientists later realized that bacteria were converting the toxic vent minerals into usable forms of energy through a process called chemosynthesis, and this provides food for other many other vent organisms. One of these organisms is the tubeworm (Riftia pachyptila), which according to the Woods Hole Oceanographic Institution, lives in a symbiotic relationship with bacteria; allowing them to survive. These tubeworms begin as larvae and with their symbiotic relationship, can grow as much as 31 inches a year. Another organism that survives at this depth in part to the mineral rich environment is the vent shrimp (Rimicaris exoculata). These shrimp have developed a light sensing organ that is a photo receptor which, according to the Woods Hole Oceanographic Institution, scientist have determined to be used to see the thermal radiation found in these vents which can reach over 350 Celsius.
Hydrothermal vent structures are characterized by different physical and chemical factors, including the minerals, temperatures, and flow levels of their plumes. Black smokers emit the hottest, darkest plumes, which are high in sulfur content and form chimneys up to 18 stories tall, or 55 meters (180 feet). The plumes of white smokers are lightly colored and rich in barium, calcium, and silicon. Compared to black smokers, white smokers usually emit cooler plumes and form smaller chimneys. Vents with even cooler, weaker flows are often called seeps. They appear to shimmer because of differences in water temperatures or bubble because of the presence of gases, like carbon dioxide.
Source: Woods Hole Oceanographic Institution http://www.whoi.edu/ and National Geographic http://education.nationalgeographic.com/education/media/deep-sea-hydrothermal-vents/?ar_a=1
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