Major Study: Over 21% of Oceans Darken

A major study by the University of Plymouth and Plymouth Marine Laboratory has found that over 21% of the world's oceans, covering more than 75 million square kilometers, have significantly darkened in the past two decades. The darkening, known as 'ocean darkening,' is attributed to agricultural runoff, increased rainfall, changes in algal blooms, and rising sea surface temperatures, leading to the photic zone shrinking by over 50 meters in more than 9% of the ocean and over 100 meters in 2.6%. This reduction in sunlight penetration threatens marine biodiversity, destabilizes ecosystems, and forces light-dependent species into smaller, shallower habitats. The research, based on nearly 20 years of satellite data and advanced modeling, warns that the trend could undermine the ocean’s ability to support life, regulate climate, and provide essential ecosystem services, including fisheries and oxygen production. While about 10% of the ocean has become lighter due to regional variations, the overall trend is concerning. Scientists emphasize the urgent need to address pollution, climate change, and ocean health to protect marine ecosystems.