Physical versus biological spring transition: 2005

Abstract

In 2005, the onset of spring conditions in the physics of the coastal ocean (lowered sea level, spin‐up of vertically‐sheared equatorward coastal jet) came about 50 days later than average off Newport Oregon, on May 24. There was a further delay of 50 days before the subsurface upwelled water penetrated into the anomalously stratified surface layer, becoming most available for biological activity. The warm anomaly in sea surface temperature which provided the surface cap was observed at mid‐shelf locations from Washington to central California, but it ended sooner south of Oregon. Biological impacts of these delays to several trophic levels have been reported.