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(NewsNation) — More than 20% of the Earth’s oceans have darkened over the last 20 years, potentially leaving some marine life in the dark, according to new research from the University of Plymouth.
Researchers observed darkening in the photic zone of the oceans, where light filters through water in a sufficient enough way to sustain species that rely on sunlight and moonlight.
It’s estimated that 90% of marine life lives in this zone, which typically extends to a depth of 200 meters. Less sunlight means the vital species that live there might suffer, potentially shocking global fish stocks and disturbing food chains on land and sea.
Between 2003 and 2022, roughly 30 million square miles of ocean saw photic zones darken. That’s the same size as Europe, Africa, China and North America’s land areas combined.
Without light to guide them, some marine species could have biological processes thrown out of whack, reproductive cycles altered and more.
“The darkening of the global ocean represents a reduction in the depth to which photobiology driven by the moon and the sun can take place, and as such constitutes a globally widespread form of habitat loss that remains unquantified,” the research reads.
Researchers posit that the darkening is a potential product of algal bloom changes, shifts in surface temperatures or artificial light changes. Notably, the spans of affected oceans are not limited to coasts, which previously were mainly associated with the phenomenon.
But it is not all darkening doom — researchers also noted brightening in 10% of the ocean, around 14 million square miles.
It’s important to note that researchers hold that their two decades of data are “nonetheless insufficient to completely rule out” the possibility that the trends are simply natural changes over decades.
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