For Cassin’s auklets, robin-sized seabirds of the northeast Pacific, the winter of 2014 was a disaster. Over the course of a few months, more than 9,000 washed up on beaches from British Columbia to California. Almost immediately, scientists hypothesized that the deaths were somehow related to a massive marine heatwave, known as the Blob, that went on to ravage the coastal ecosystem from 2013 to 2015.
But it was only recently that a group of researchers confirmed the Blob as the culprit. In a new study, University of Washington ecologist Timothy Jones and his colleagues chronicle how these birds went from feast to famine.
The Blob took over the northeast Pacific in the fall of 2013, when a ridge of abnormally high atmospheric pressure parked itself over the region. The ridge slowed the wind that drives deep-sea upwelling, which typically brings cold, nutrient-rich water up to the surface.
The Cassin’s auklets were unaffected at first because an oasis of cool upwelling persisted close to their breeding colonies. But in the fall, the auklets migrated south. They congregated in the few cool zones that remained near the coast.