Now that you've read the headline, here's the brutal research result: fecal bacteria are likely lurking in that sunny beach where you've lain in the sun. Seems those micro-organisms can find the damp sand about as comfortable a medium as, say, some human's lower intestine.The research also indicates that clean offshore water does NOT mean the beach itself is healthful.
To make it even worse, the little beasties and plants don't just survive in the sand, they multiply. Thus near-shore water could actually be constantly re-polluted by beachy bacteria and other micro-organisnms derived from human sewage. So it may not simply be coral reefs that are being hurt by sewage run-off into the ocean.
Talk about cleantech: truly cleaning up our zillions of gallons of sewage run-off looks like a great business as our planet becomes ever more crowded and water continues to increase in value as a limited, non-rewable resource.