A coral species that is found in abundance from Indonesia eastward to Fiji, Samoa, and the Line Islands rarely crosses the Eastern Pacific Barrier toward the coast of the Americas, according to a team of researchers led by Iliana Baums, an assistant professor of biology at Penn State University. Darwin hypothesized in 1880 that most species could not disperse across the marine barrier, and Baums's study is the first comprehensive test of that hypothesis using coral. The results of the scientific paper, which will be published in the journal Molecular Ecology, has important implications for climate-change research, species-preservation efforts, and the economic stability of the eastern Pacific region, including the Galapagos, Costa Rica, Panama, and Ecuador.
The Eastern Pacific Barrier (EPB) -- an uninterrupted 4,000-mile stretch of water with depths of up to 7 miles -- separates the central from the eastern Pacific Ocean. In his writings, Darwin had termed this barrier "impassable" and, since Darwin's time, scientists have confirmed that many species of marine animals cannot cross this oceanic divide. However, until now, researchers had not performed a comprehensive analysis of the impact of the barrier on coral species. "The adult colonies reproduce by making small coral larvae that stay in the water column for some time, where currents can take them to far-away places," Baums said. "But the EPB is a formidable barrier because the time it would take to cross it probably exceeds the life span of a larva."
To test whether or not coral larvae are able to travel across the barrier, Baums and her team chose a particularly hearty species called Porites lobata. "Compared with other coral species, Porites lobata larvae seem able to survive for longer periods of time; for example, the weeks that are required to travel across the marine barrier," Baums said. "This species also harbors symbionts in its larvae that can provide
|Contact: Barbara Kennedy|