BOSTON: Underwater meadows of seagrass offer important protection against pollution to both humans and coral reefs, but are in jeopardy worldwide due to climate change, sewage and agricultural runoff, researchers said Thursday.

Places with healthy seagrass —where sponges, clams, small fish and other filter feeders thrive—can reduce bacteria that is harmful to both people and marine life by up to 50 percent, said the study in the journal Science.