“The Blob”: how a marine heatwave killed 4 million seabirds

Between 2014 and 2016, “The Blob” was an intense marine heatwave that killed an estimated 4 million seabirds as temperatures up to 3 degrees Celsius above average left them without food.

Between 2014 and 2016, an enormous marine heatwave called “The Blob” devastated the northeastern Pacific Ocean and killed an estimated 4 million seabirds. This was considered the worst environmental disaster ever recorded for these species and showed the devastating impact of climate change on marine ecosystems.

The warmth persisted for about two years, increasing the temperatures of the ocean surface by as high as 5.4°F above the mean-an unprecedented anomaly that interrupted the whole food chain. Instantly, seabirds like murres could not find enough food, which resulted in their mass die-offs. The beaches from Alaska to California were filled with carcasses, a vivid expression of the extent of the disaster.

A grim decline in seabird ppopulations

A University of Washington study tracked the aftermath of this event in 13 seabird colonies from 2008 through 2022. The shocking results showed that the seabird population in the Gulf of Alaska dropped by half, while in the eastern Bering Sea, it crashed by 75%. The decline was much worse than initially estimated, with mortality rates as high as eight times higher than expected.

Heather Renner, a wildlife biologist and co-author of the study, called the findings a gut punch. In fact, for the birds, “The Blob” impacted more than just heat stress; it drastically changed food availability and left many species unable to survive.

Other marine species did not get away unscathed either. In the Bering Sea, millions of snow crabs starved because of the heatwave, which had already upset the entire food chain. Scientists warn that with ocean temperatures continuing to rise, such events will be increasingly common-a severe threat to marine biodiversity.

Seven years later, there is no sign of their recovery. It was estimated that before the disaster, there were about 8 million murres in the region. These days, the colonies are sparse, and a recovery seems unlikely. That grim prospect underlines the need to address climate change if marine ecosystems and species dependent on them are to be saved.

Source: Science