Elephant Seals Investigate the Biggest Sea Heat Wave Ever Recorded

Scientists have placed sensors on elephant seals to better understand the sea heatwaves, unfortunately, more and more frequent. Their study reveals valuable information to explain the proponents of the “blob”, this phenomenon that occurred off the Pacific Ocean between 2013 and 2015.

You probably know the “blob”this giant cell endowed with an incredible learning ability which has fascinated the scientific community for several years. But the word “blob” refers to another equally impressive scientific phenomenon: heat wave observed off the North Pacific Ocean between 2013 and 2015, which had dramatic consequences on the wildlife who populates these ocean areas.

” In the summer of 2015, two years after the Blob appeared, only 166 humpback whales returned to Glacier Bay, Alaska, down 30% from 2013. All humpback calves seen in Glacier Bay that year later disappeared and are presumed dead. And the bodies of 28 humpback whales and 17 whales common washed up on beaches in Alaska and British Columbia in Canada “, Explain an article published in the journal Science in January 2019.

A marine heat wave designates an abnormal and prolonged warming of the waters. The 2013-2015 “blob” represents the longest and most intense recorded to date. To better understand the proponents of this extraordinary climatic event, a team of American researchers from the University of California at Santa Cruz (UCSC) decided to use sea ​​elephants to explore the funds submarines of this area.

Elephant seals, outstanding divers

Published in the journal Journal of Geophysical Research: Oceansthe study was carried out using sensors recording the depth, temperature and salinity of water, in order to follow the migrations of elephant seals nearly 10,000 km across the Pacific. This species submarine of the seal family was not chosen at random: it is able to dive more than 100 meters deep!

” Elephant seals collect data at different locations than existing oceanographic platforms “, precise in a press release Christopher Edwards, professor of ocean science at UCSC, who led the research.

Will sea heat waves become the norm?

Data collected from sensors placed on elephant seals during the Blob revealed that abnormally warm temperatures extended 1,000 meters below the surface. Reheating beneath the surface persisted in 2017, long after surface temperatures have returned to normal, the study notes.

According to the researchers, these anomalies temperatures are so deep that they are unlikely to be due to mixing from the surface. One of the hypotheses considered is that the exceptionally warm waters were transported north from the south. Indeed, changes at the surface may have transiently altered deeper currents to draw southerly waters northward.

This climatic phenomenon is all the more worrying as the waves of heat marines are likely to become more frequent as the planet warms, warn the authors of the research. ” Similar to terrestrial heat waves, over the past decade we have seen a dramatic increase in the frequency and magnitude of marine heat waves. The more information we gather, the more we will be able to understand what is happening and address the challenges “, conclude the latter.