The National Oceanic and Atmospheric Administration (NOAA) just recently issued a report that the second largest marine heatwave ever detected is forming in the northern Pacific Ocean. Marine heatwaves are defined as an extended period of higher than average temperatures detected in an area of the ocean. They are specifically identified based on the expected temperatures for the time of year and location in which they appear.
From roughly 2014 to 2016, the largest marine heatwave ever recorded dramatically affected marine life and weather patterns along the West Coast of the United States. This event was nicknamed The Blob due to its amorphous shape and dark color as it appears in weather satellite imagery.
During this time, the warm surface water temperatures caused an outbreak of toxic algae blooms that resulted in the deaths of many species of fish and birds. The outbreak also caused the closing of shellfish and crab fisheries in California due to contamination concerns.
The entire marine food web gets disrupted by these heatwaves. The warmer water temperatures affect the lifecycles of sea life from the smallest plankton and krill all the way up to the larger species like seals and whales. A record number of sea lions became stranded and malnourished during the last heatwave.
Another way these marine heatwaves affect life along the coast is by changing weather patterns. Winter storms that bring rain to the west coast are mostly driven by cool surface temperatures and winds. These conditions change when the water is warm. This results in the likely situation of another severe drought for western states. Wildfires, likewise, become more of a threat during this hot and dry period.
So far, scientists at NOAA and other ocean researchers are keeping an eye on this newly emerging marine heatwave. It does not reach nearly as deep as the previous one, but concern is still high as the warm mass of water continues to develop and spread south.
An organization known as the Marine Heatwaves International Working Group is closely monitoring the current developments off the west coast as well many other heatwave events around the world. They provide educational and informative updates through their website so the public can stay advised. They also have developed a marine heatwave tracker where each anomaly around the globe can be viewed and followed.