National Geographic : 1990 Dec
ICA IAT O AlI L l A GE G AP I MA A INEI Lake Baykal's Deep Vent: A Freshwater First Joint Soviet-American scientific expedition cosponsored by the National Geographic Society has discovered a hot vent in Lake Baykal in the Soviet Union-the first time a freshwater spring has ever been found that supports such a diversity of deep water life, including fish, sponges (right), worms, and snails. The vent is about 1,350 feet down in Frolikha Bay in the northeastern cor ner of the world's deepest-5,370 feet-and perhaps oldest lake. Scien tists estimate that the lake basin was formed about 25 million years ago. Kathleen Crane of Hunter College, the group's chief scientist, said the pres ence of hot springs can be a sign that the area beneath the lake is slowly spread ing apart, creating a rift valley. Fewer than 20 hydrothermal vent fields have been found in the world's oceans since the first ones were discovered in the Pacific's Galapagos Rift (NATIONAL GEOGRAPHIC, October 1977). Crane's team found the vent site by studying geothermal maps, which showed several areas of high heat flow in the lake floor. The maps of Lake Baykal were prepared by Vladimir Golubev, a Soviet geophysicist who was with the group aboard the research vessel Vereshchagin, operated by the team's cosponsor, the Limnological ALLBY EMORYKRISTOF, NGS Institute at Baykal. The scientists low ered a sled containing a camera and a temperature and salinity sensor and located the spring after several passes. As part of the expedition the team used towed sleds, manned submers ibles, and remotely operated vehicles (top left) to explore and photograph animal life, such as this sculpin seen against the steep wall of the lake (top right) and crustaceans atop sponges (left). Baykal holds some 2,600 forms of life, more than half of them found nowhere else on earth.