PROVIDENCE, R.I. [Brown University] One of biggest factors promoting the diversity of coastal ocean life is how fast the water flows, according to new research by ecologists at Brown University. Experiments and observation in Palau, Alaska, and Maine showed that the faster the flow, the greater the number of invertebrate species that live on rocks under the water.
The findings, published the week of Nov. 15 in the journal Ecology Letters, could help improve management of delicate and complex coastal ecosystems, said James Palardy, a former Brown doctoral student and the paper's lead author. Finding the fastest water could point scientists to areas where diversity is likely greatest and perhaps especially worthy of protection and to zones where invasive species could establish their first beachheads.
Jon Witman, professor of ecology and environmental biology and Palardy's co-author on the paper, said the results were clear and consistent at all three regions, including in Maine and Alaska where they experimentally manipulated water flow speed.
"It totally blew us a way that we got almost identical results in two marine regions of the world separated by 4,000 miles with completely different regional diversities, and no species shared in common," Witman said. "It's a wake-up call saying that water flow is a really strong predictor of how many species are present in a particular area of the ocean."
The reason why faster flow seems to promote diversity, Witman said, is that it allows for the larvae of rock-dwelling invertebrates, such as barnacles, sea squirts, corals and sponges, to spread farther. Although the environments are quite different, it's somewhat analogous to how trees and flowers can disperse their seeds farther in a stiff wind.
Palardy and Witman are not the first to observe a connection between water flow and diversity, but they are the first researchers to prove
|Contact: David Orenstein|