Scientists have found that more than 20% of the oceans have darkened over the past 20 years, shrinking the sunlit “photic zone,” home of 90% of marine life. The darkening, revealed through satellite data and modeling, is caused by increased sediment and organic material, and changing conditions that block light. In some areas, the photic zone has become up to 330 feet shallower, forcing marine organisms to compete closer to the surface. The trend could disrupt ecosystems, affect fisheries and weaken the ocean’s role in regulating climate.

adapted with permission from Earthweek.com