Ocean heat waves often lurk out of sight

Warmer-than-usual waters can harm ecosystems and are often undetectable at the ocean’s surface

A large school of small fish swim in the ocean, taken from the vantage point of the school swimming right past the viewer.

Ocean heat waves, which can be detrimental to marine ecosystems, often remain hidden from view.

Global_Pics/iStock/Getty Images Plus

Heat waves don’t just strike on land — they can also occur in the ocean. And roughly a third of marine heat waves aren’t detectable at the ocean’s surface, a new study reports. The findings, published in the December Nature Geoscience, suggest that far more of these potentially harmful events might be occurring than previously believed.