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| Inside the ALVIN |
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| ALVIN on Deck |
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Deep-Sea Submersibles: The ALVIN
scientists travel down to the ocean floor using a submersible to make first hand observations of the sulfide structures and the life forms that live on them and to collect samples. Deep-sea submersibles like the ALVIN are special because they can go to greater depths than ordinary submarines (depths greater than 2,000 meters). The ALVIN is the deep-sea research submersible owned by the United States government. It can carry three passengers and dives to a maximum depth of 4,000 meters. Conditions inside the ALVIN are very cramped. Three people, usually two scientists and a pilot, can barely fit. The scientists and pilot sit on the floor and peer out of three small portholes made of very thick glass. Sunlight penetrates through only the upper 1,000 meters of the ocean. The ocean below this depth is therefore totally dark. The ALVIN carries spotlights to provide light for navigation and observations, and digital cameras for photography and videography. The ALVIN has mechanical arms and a basket for storing samples. Scientists can use ALVIN's mechanical arms to collect pieces of sulfide structures, ocean floor rocks, life-forms, and samples of water, which are then stored in the basket. A total dive might last eight to ten hours, including two to four hours of travel time down and up, and four to six hours of "bottom" time, to explore the ocean floor and collect samples. The ALVIN is not big enough to have a bathroom. If required (and usually ALVIN passengers try very hard not to need it!) bottles are used instead.
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| ALVIN on the Sea Floor |
The international research community has a number of deep-sea submersibles. These submersibles differ mainly in their depth capabilities. There are several criteria in the selection of a research vehicle:
- ability to perform research
- cost efficiency for the depth of the dive
- equipment is in the region and won't take weeks to reach you
- equipment is available for use
Scientists choose the vehicle that will dive deep enough to reach their research destination and that is in the region around the time of their expedition.
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