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Dive and Discover: Introduction

Expedition 4, March 27–May 5, 2001

Dive and Discover’s first expedition of 2001 was a 40-day-long voyage to explore for hydrothermal vents at the mid-ocean ridge in the central Indian Ocean, one of the most remote places on Earth. Like 16th century explorers who traveled across the Indian Ocean in search of new lands and exotic spices, the scientists and crew on Expedition 4 searched for new hydrothermal vent animals and ancient bacteria—missing links that can help explain how the fauna living at hydrothermal vents in the Atlantic and Pacific Oceans are genetically related.
Since hydrothermal vents were first discovered in 1977 on the Galápagos Rift, scientists have learned that communities of animals along the mid-ocean ridge are very different in the Pacific and Atlantic Oceans. Because deep water flows from the Atlantic, into the Indian Ocean, and then into the Pacific, the Indian Ocean provides the link. Would the same types of vent animals found at Atlantic and Pacific vent sites also inhabit Indian Ocean hydrothermal vents? How do these animals and their larvae migrate along the 60,000-kilometer- (36,000-mile) long global mid-ocean ridge system, and how do they get across the deep fractures, or transform faults, that separate segments of the ridge crest? Are there specific genetic differences between vent animals and the bacteria they eat that can help explain how hydrothermal vent fauna first evolved, and how they relate to the evolution of early life on Earth?
A team of biologists, microbiologists, geneticists, chemists, and geologists from eight US universities and institutions set out from the Seychelles islands aboard the research vessel Knorr to seek answers to these questions. The scientists worked with the ship’s crew and members of WHOI’s Deep Submergence Operations Group (DSOG), using deep-sea vehicles that included the Argo II mapping system, the DSL-120 sonar, and the remotely operated vehicle (ROV) Jason to survey and sample the hydrothermal vents. A conductivity/temperature/depth water sampling system was also important to the operations.

The first site visited was near 25°S where a team of Japanese scientists using ROV Kaiko discovered the Kairei Hydrothermal Field in August 2000, and Expedition 4 scientists went on to discover more new hydrothermal activity in the Indian Ocean.
This expedition took over five years to plan and organize. Join the scientists, technicians, and crew of R/V Knorr on this historic voyage as they Dive and Discover in the far reaches of the Indian Ocean.

Originally published: March 1, 2002