Heat Waves Found Raging Not Only on Land but Also at the Ocean's Surface

Bottom marine heat waves affect species like cowcod, a Pacific coast rockfish that lives at depths up to 1,500 feet, shown here with an assemblage of brittle stars.

It is thought that the heat waves raging at the ocean's bottom have a significant influence on how healthy the ocean's ecosystems are.

Harm to marine life

Researchers' evaluation of the marine environment is the first of its kind, and they have found that heat waves are pounding the ocean floor. Extreme weather conditions are now known to be harming the marine environment in addition to the planet's land.

The team attempted to comprehend the basic characteristics of warm ocean temperature extremes, also known as marine heatwaves, in the research that was published in the journal Nature Communications. The research found that, with a bottom depth ranging from 0.5 degrees Celsius to 3 degrees Celsius, the intensity and duration of bottom marine heatwaves vary significantly.

Statement by Dillon Amaya

“Researchers have been investigating marine heat waves at the sea surface for over a decade now. This is the first time we’ve been able to really dive deeper and assess how these extreme events unfold along shallow seafloors," lead author Dillon Amaya, a research scientist with NOAA, said in a statement.

This visualization depicts bathymetric features of the western Atlantic Ocean Basin, including the continental shelf, captured by satellite.

Researchers study

The productivity and distribution of organisms as small as plankton and as big as whales are thought to be significantly impacted by the heat waves roiling at the ocean floor, which are thought to have a significant global effect on the health of ocean ecosystems.

The effects of marine heat waves on the ocean's surface have been the focus of study thus far, which scientists claim can also serve as indicators of a variety of physical and biochemical ocean characteristics of delicate marine ecosystems, simplifying analyses.

It should be emphasized that the ocean, which has warmed by about 1.5 degrees Celsius over the past century, has absorbed 90% of the excess heat from global warming. Over the past ten years, marine heat waves have occurred about 50% more frequently.

"Warm ocean temperature extremes — known as marine heat waves (MHW) — can dramatically impact the overall health of marine ecosystems around the globe, including changing the regional distribution of marine species, altering primary productivity, and increasing the risk of negative human-wildlife interactions," researchers said in the paper.

Ling cod, like this one caught off of Humboldt Bay Jetty in California, are a member of Pacific groundfish communities vulnerable to impacts from bottom marine heat waves.

The early 19th century's weather was recreated by NOAA experts. They discovered that bottom marine heat waves typically last longer than their surface equivalents on the continental shelves surrounding North America. The unexpected finding that bottom marine heat waves can happen even when there is little to no surface warming has important ramifications for the management of economically significant fisheries.

Statement by Michael Jacox

“We know that early recognition of marine heat waves is needed for proactive management of the coastal ocean. Now it's clear that we need to pay closer attention to the ocean bottom, where some of the most valuable species live and can experience heat waves quite different from those on the surface,” co-author Michael Jacox, a research oceanographer added.