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Happy as a Clam

Few things make a deep-sea biologist like Tim Shank happier than obtaining samples of organisms from a hydrothermal vent site on the seafloor. These giant clams were retrieved by the Alvin submersible during a 2002 expedition to the Galápagos Rift, where previously unknown deep-sea animals were first discovered in 1977 living around hydrothermal vents. The discovery of chemosynthetic life, living on chemicals in the absence of light, revolutionized our understanding of where and how life could exist on Earth and other planetary bodies. Living in these clams are bacteria that use sulfide from the vents to grow and, in turn, are eaten by the clams. (Photo courtesy of Woods Hole Oceanographic Institution Archives)