image: Large acorn barnacles (Semibalanus cariosus), a dominant space occupier in rocky intertidal communities along the west coast of North America. The hummocked growth form (tall, thin, with a tendency towards a trumpet shape) induced by crowding is evident. Mussels (Mytilus spp.; black) are also visible. view more
Credit: Jane Lubchenco
In 2005, a delay in the arrival of a seasonal, nutrient-rich ocean current off the coast of Northern California and Oregon led to reduced influx of barnacle and mussel larvae to rocky shores, researchers report. The coastal ecosystem off Northern California and Oregon owes its richness to southward winds that move warm ocean surface water offshore during the spring and summer. The warm water is replaced by cold, nutrient-rich water from the deep ocean. John Barth and colleagues report that in 2005 the southward winds were delayed, leading to a late arrival of the cold, nutrient-rich water. The change in ocean currents had several ecological consequences: high ocean temperatures, low nutrient levels, and low abundance of phytoplankton. The researchers also observed that fewer barnacle and mussel larvae settled onto rocks during spring and early summer of 2005, likely due to the low availability of food. In late summer, stronger than usual nutrient-rich currents arrived at the coast, leading to a recovery of mussel, but not barnacle, recruitment. Understanding the ecological consequences of changes in coastal ocean currents is important, the researchers say, because if global warming continues, climate models predict ocean current alterations like the one observed in 2005.
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EMBARGOED: NOT FOR PUBLIC RELEASE BEFORE: 16 FEBRUARY 2007, 6:00 PM U.S. Eastern time / 11:00 PM London time 17 FEBRUARY 2007, 8:00 AM Japan time / 10:00 AM Australia Eastern time
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Article #00462: “Delayed upwelling alters nearshore coastal ocean ecosystems in the Northern California current” by John A. Barth, Bruce A. Menge, Jane Lubchenco, Francis Chan, John M. Bane, Anthony R. Kirincich, Margaret A. McManus, Karina J. Nielsen, Stephen D. Pierce, and Libe Washburn
MEDIA CONTACT: John A. Barth, College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, OR; tel: 541-737-1607; e-mail: barth@coas.oregonstate.edu
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