Brace yourselves: it's looking like the "Blob" is back in town.
Around five years ago, a vast “blob” of warm ocean water was detected in the Pacific Ocean just off the West Coast of the US and Canada. After being absent for a couple of years, it now appears that “the Blob” is making a monstrous comeback – and that spells bad news for the Pacific’s marine ecosystems.
The NOAA has reported a rise in sea surface temperatures off the West Coast of North America with striking similarities to the early stages of the "Blob” from 2014-2016. Their satellites have detected temperature anomalies, more than 3°C above average in areas, across a portion of the ocean that covers more than 1,553,000 square kilometers (600,000 square miles), an area larger than Texas, California, and Montana combined.
This warming expanse is already being defined as the second-largest marine heatwave in terms of area in the northern Pacific Ocean in the last 40 years. However, if their forecasts are correct, this is just the beginning.
“It’s on a trajectory to be as strong as the prior event. Already, on its own, it is one of the most significant events that we’ve seen,” Andrew Leising, a research scientist at NOAA Fisheries’ Southwest Fisheries Science Center in California, said in a statement.
The story of this heatwave and the "Blob" is closely linked to the wind. This summertime saw relatively weak winds over the Northeast Pacific Ocean. Paired with a persistent ridge of high pressure over Alaska and a chunk of low pressure between Hawaii and the West Coast, this allowed surface water to gently heat up without being disrupted, leading to rising sea surface temperatures.
Based on the effects of the last "Blob", scientists are starting to fret about the potential knock-on effects this could have on the surrounding marine ecosystems. The heatwave has already sparked the largest toxic algal bloom recorded on the West Coast, which has wreaked havoc on local crabs, clams, and other shellfish for months.
Fish, including salmon fisheries, have suffered due to changes in the disruption of krill, one of their best food sources. In turn, the lower returns of fish can affect predator disruptions. As just one example, sea lions have been forced to travel further from their usual rookeries in the Channel Islands off Southern California, leading to thousands of young California sea lions becoming stranded on beaches.
However, it isn’t all doom and gloom. This time around, scientists are armed with the knowledge from the previous "Blob", so they are slightly better prepared. Current forecasts suggest the heatwave could continue for months; however, there is also some indication that the blob could perhaps dissipate fairly quickly, especially if the weather pattern breaks or a cold winter hits the Northern Hemisphere.
For now, though, researchers are just going to have to wait and see.
“There are definitely concerning implications for the ecosystem. It’s all a matter of how long it lasts and how deep it goes,” added Nick Bond, a research meteorologist with the Joint Institute for the study of the Atmosphere and Ocean in Seattle, who is credited with naming the "Blob" in 2014.