Mussels are her specialty. Bob Vrijenhoek, a senior scientist at the Monterey Bay Aquarium Research Institute in Moss Landing, California, takes a different approach. Members of Vrijenhoek s research group are participating in the Indian Ocean expedition. Hydrothermal vents offer a unique opportunity for biogeographers because the underwater environment is affected by fewer factors than are land environments. They are isolated from what goes on above.
Individual vents remain active for anywhere from a few decades to a few thousand years.
When a vent shuts off, the adult animals living there die. Yet as soon as a new vent emerges, it is rapidly colonized. Within a few years, a new vent undergoes a complete transformation from uninhabited to fully populated. By studying the similarities and differences among the animals that live at different vents, scientists have begun to piece together a picture of how organisms move from one vent to another, what the natural barriers are to such movement and how the geography of the deep ocean affects the evolution of the species that inhabit it. Although similar types of animals can be found at both Atlantic and Pacific vent sites, there is more similarity among the vent ecosystems along the same ridge than there is between the two ridges.