Global Warming Research Today is a free monthly online journal that collates and summarizes the latest research about Global Warming, including details on causes, effects, impact, facts, myths, information. | ||||||||
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Delayed upwelling alters nearshore coastal ocean ecosystems in the northern California current.Barth JA, Menge BA, Lubchenco J, Chan F, Bane JM, Kirincich AR, McManus MA, Nielsen KJ, Pierce SD, Washburn L College of Oceanic and Atmospheric Sciences and Department of Zoology, Oregon State University, Corvallis, OR 97331, USA. barth@coas.oregonstate.edu Wind-driven coastal ocean upwelling supplies nutrients to the euphotic zone near the coast. Nutrients fuel the growth of phytoplankton, the base of a very productive coastal marine ecosystem [Pauly D, Christensen V (1995) Nature 374:255-257]. Because nutrient supply and phytoplankton biomass in shelf waters are highly sensitive to variation in upwelling-driven circulation, shifts in the timing and strength of upwelling may alter basic nutrient and carbon fluxes through marine food webs. We show how a 1-month delay in the 2005 spring transition to upwelling-favorable wind stress in the northern California Current Large Marine Ecosystem resulted in numerous anomalies: warm water, low nutrient levels, low primary productivity, and an unprecedented low recruitment of rocky intertidal organisms. The delay was associated with 20- to 40-day wind oscillations accompanying a southward shift of the jet stream. Early in the upwelling season (May-July) off Oregon, the cumulative upwelling-favorable wind stress was the lowest in 20 years, nearshore surface waters averaged 2 degrees C warmer than normal, surf-zone chlorophyll-a and nutrients were 50% and 30% less than normal, respectively, and densities of recruits of mussels and barnacles were reduced by 83% and 66%, respectively. Delayed early-season upwelling and stronger late-season upwelling are consistent with predictions of the influence of global warming on coastal upwelling regions. Published 15 March 2007 in Proc Natl Acad Sci U S A, 104(10): 3719-24.
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