Over 20% of the world's oceans have grown darker in the last two decades, a phenomenon scientists call "ocean darkening". According to a University of Plymouth study published in Global Change Biology, reduced sunlight penetration is linked to changes in algal blooms, sea surface temperatures, and artificial light.
Between 2003 and 2022, more than 9% of the ocean saw light levels drop by over 50 metres, with 2.6% losing over 100 metres of light.
Dr Thomas Davies, marine conservation expert at the university, said this reduces habitat for creatures that depend on natural light for survival and reproduction.
The darker seas may affect marine ecosystems, the global food chain, and even oxygen production.
Professor Tim Smyth of Plymouth Marine Laboratory warned that species might move closer to the surface, intensifying competition for food and disrupting the balance of marine life.
“These shifts are a genuine cause for concern,” Davies emphasised.
