28 APRIL 1998. PACIFIC OCEAN: SPECIATION
Turtox News reports that changes in currents during ENSO conditions may allow some species to cross the Eastern Pacific Barrier , a 5,400-kilometre barrier of deep water between the central and the eastern Pacific which restricts movement of shallow-water marine species. The Barrier has been in place since the Cenozoic, 65 million years ago, and has no island stepping stones. Lessios and colleagues found genetic evidence suggesting that sea urchins have exchanged genetic material across the barrier. They speculate that ENSO conditions may facilitate this exchange.--VIA Neal Smith <SMITHN@tivoli.si.edu>