❖ Marine Heat Waves (MHWs) are defined by the unusual warming of ocean waters.

❖ In recent years, global warming has made MHWs more frequent and intense.

❖ MHWs have typically been measured by observing temperatures at the ocean surface.

❖ The Researchers found that MHWs deep in oceans may be “significantly underreported”

❖ Huge loops of swirling current, sometimes hundreds of kilometres across and reaching down over 1,000 metres.