The Environmental Threat You’ve Never Heard Of



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The Environmental Threat You’ve Never Heard Of - Hakai Magazine

It’s called coastal darkening, and scientists are just beginning to explore it.

Coastal waters around the world are steadily growing darker. This darkening—a change in the color and clarity of the water—has the potential to cause huge problems for the ocean and its inhabitants.

“It’s affecting the quality of the sea we know,” says Oliver Zielinski, who runs the Coastal Ocean Darkening project at the University of Oldenburg in Germany. These “changes in the physics will lead to biological changes,” he adds.

Some of the causes behind ocean darkening are well understood: fertilizer enters the water and causes an algal bloom, or boats stir up light-blocking silt as they move. But other causes are murkier. During heavy rains, for instance, organic matter—primarily from decaying plants and loose soil—can enter the ocean as a brown, light-blocking slurry. This process is well documented in rivers and lakes, but has largely been overlooked in coastal areas.