Diversity hot spots at cold seeps?

Hydrothermal vents and cold seeps were discovered more than 20 years ago, yet remarkably little is known about the biodiversity of these chemosynthetic ecosystems. Deep-sea vents and seeps occur in very different geological settings, yet in both types of systems, microbial primary production supports an abundance of large invertebrates, such as giant tubeworms, clams, and mussels.

These animals in turn provide refuge for a diverse invertebrate fauna. Because seeps are considered to be more stable and less toxic than vents, ecologists expected that diversity would be greater at seeps than at vents, but this hypothesis remained untested until now. In the most recent issue of Ecology Letters, researchers at the College of William and Mary report that diversity is indeed greater in seep mussel beds compared to vent mussel beds.

Lower diversity at vents may be a consequence of a challenging physiological barrier to invasion at vents than at seeps. Moreover, diversity at vents is lowest where spacing between vents is extensive, suggesting that risks of extinction due to
limited dispersal may be important in governing biodiversity in the deep sea.