Facing rising temperatures, a spike in acidity driven by an influx of carbon, mass habitat destruction, and inescapable pollution, the world's oceans haven't had it easy. But in an ominously literal sense, the situation may be even darker than we realized.

New research indicates that more than a fifth of the global ocean has darkened over the past two decades, with the depths that sunlight can penetrate significantly retreating.

The findings, published in a new study in the journal Global Change Biology, describe a worrying shrinking in the ocean's crucial photic zones — the uppermost layer where 90 percent of all marine life, from fish to photosynthesizing plankton, reside.

This "reduces the amount of ocean available for animals that rely on the Sun and the Moon for their survival and

See Full Page