Climate Change

Scientists discover intense heatwaves at the bottom of the ocean

These heatwaves have dramatically impacted the health of ocean ecosystems around the globe

Published: Friday 24 March 2023

Scientists, for the first time, have found evidence of heatwaves creeping at the bottom of the oceans. The studies till now concentrated on the heatwaves on the surface and sub-surface of the ocean.

Now, new modelling led by researchers at the US National Oceanic and Atmospheric Administration (NOAA) shows that marine heatwaves can unfold deep underwater even when there is no detectable warming signal above.

The study published in the journal Nature Communications further tried to understand the characteristics of these heatwaves and the impact it has on the marine world. NOAA scientists focused on the west and east coasts of North America, using data spanning three decades.

The result shows that marine heatwaves have a high intensity, varying from 0.5 degrees to up to 3 degrees Celsius in the depths of the oceans. The team also found that bottom marine heat waves can also occur with little or no evidence of warming at the surface.

The study further states that the ocean has gotten warmer by about 1.5 degrees Celsius over the last 100 years and has taken in 90% of the extra heat from global warming. The frequency of marine heat waves has also increased by about 50% in the last ten years.

These heatwaves have dramatically impacted the health of ocean ecosystems around the globe, disrupting the growth of organisms from plankton to whales. The marine heatwave known as ‘The blob’ formed in 2013 is a perfect example of the damage heatwaves can bring to the marine ecosystem.

Developed off the coast of Alaska, this widespread, prolonged heatwave destroyed fisheries, initiated toxic algal blooms and had a widespread impact on all marine lifeforms.

The researchers say their results underscore the importance of maintaining long-term ocean monitoring systems, especially as scientists are only just beginning to understand the impacts of bottom marine heatwaves. Developing new observational capabilities could also allow the scientific world to better understand the past, present and future of Marine heatwaves.

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