The Blob (Pacific Ocean) the surface waters of the mid-latitude Pacific Ocean flipping from a cold phase to a warm phase in a cycle known as the Pacific decadal oscillation (PDO). This poorly-understood change happens at irregular intervals of years or decades. During a warm phase, the west Pacific becomes cooler and part of the eastern ocean warms; during the cool phase, these changes reverse. Scientists believe a cold phase started in the late 1990s and the arrival of the Blob may be the start of the next warm phase. The PDO phases may also be related to the likelihood of El Nino events.
The Blob (Pacific Ocean) ultimate cause of the phenomenon, but states "there's no doubt that this anomaly in sea surface temperature is very meaningful". Sea surface temperature anomalies are a physical indicator which adversely affect the zooplankton (mainly copepods) in the Northeast Pacific and specifically in the Coastal Upwelling Domain. Warm waters are much less nutrient-rich than the cold upwelling waters which were the norm till recently off the Pacific Coast. This results in reduced phytoplankton productivity with knock on effects on the zooplankton which feed on it and the higher levels of the food chain. The Northwest Fisheries Science Center, Seattle has predicted