Elephant Seals Are Supplying Info About the Blob

Medscape Staff

August 18, 2022

Elephant seals that have been tagged for biological studies are providing unexpected data about the marine heatwave known as the North Pacific Blob, which continued from 2013 to 2015, according to marine biologists from the University of California, Santa Cruz.

What to know:

  • Decades of studying the months-long migrations of tagged and tracked elephant seals in the North Pacific Ocean are revealing that deeper warm-water anomalies associated with the North Pacific Blob were much more extensive than previously reported.

  • Surface warming was well documented during the largest and longest-lasting marine heatwave on record, which was called the North Pacific Blob. It began in late 2013 and waned in 2015.

  • The elephant seal data collected during the Blob revealed that abnormally warm temperatures extended well below the surface to a depth of about 1000 m (3280 ft) and that the subsurface warming persisted into 2017, well after surface temperatures had returned to normal.

  • Sensors on the elephant seals record depth, temperature, and salinity while the animals dive repeatedly to great depths during migrations of some 6000 miles across the North Pacific.

  • Understanding the physical processes involved in marine heatwaves as they increase in frequency, magnitude, and duration as global temperatures continue to rise will help scientists predict their onset and development and will allow people to anticipate and address the ecologic and economic consequences.

This is a summary of the article, "Extent and Magnitude of Subsurface Anomalies During the Northeast Pacific Blob as Measured by Animal-Borne Sensors," published in the Journal of Geophysical Research: Oceans on July 4, 2022. The full article can be found on agupub.onlinelibrary.wiley.com.

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