Arrhythmias in the coastal ocean off the west coast of the US

The California Current Large Marine Ecosystem has exhibited dramatic and puzzling changes in recent years.  Anomalies include changes in oceanic and atmospheric conditions that trigger severe perturbations to the normally predictable timing and intensity of upwelling.  In one extreme, upwelling is delayed, resulting in a cascade of consequences: reduced nutrient supply to surface waters, depression of phytoplankton, zooplankton, and planktivore abundances, and starvation or reproductive failures of higher trophic level consumers such as sea birds and salmon.  At the opposite extreme, upwelling is supercharged, resulting in excessive amounts of nutrients and phytoplankton blooms that fuel hypoxia and, hence, suffocation by most marine animals that cannot flee.  Severe hypoxia, never documented in shallow waters off Oregon prior to 2002, has now appeared each of the last five years.  Hypoxia in 2006 was the longest lasting (four months), largest (at least 3,000 square km and up to 2/3 of the water column), and most severe (anoxic) ever recorded in shallow waters off the west coast of the U.S.  The 2006 hypoxia and anoxia had locally devastating impacts on bottom-dwelling marine life.  Larger-scale and long-term impacts to fisheries and the ecosystem are not known.   In 2005 and 2006, both extreme states (delayed upwelling resulting in starvation and supercharged upwelling resulting in suffocation) developed in response to highly anomalous fluctuations in the timing and strength of upwelling-favorable winds.  These changes are consistent with predictions of climate change models and offer important insights into the scales and pathways of climate-driven ecological changes in upwelling ecosystems.