Dust falls through the oceans and settles on the sea floor in the same way that it settles out of the air and accumulates on furniture. But the dust in the ocean teems with life. Ocean dust, known by oceanographers and scuba divers as marine snow, helps clean the surface layer of the ocean. Scientists believe it may also bring important nutrients into the deep sea, carrying with it diverse populations of microorganisms. Mary Silver, a professor of ocean sciences at the University of California at Santa Cruz, calls an ocean dust particle a"buzzing micropolis of life."
     In the movie Titanic, marine snow is obvious. In scenes where the small submarine explores the sunken ship, floating white particles cloud the water.
     "Most people think, 'Ah, that's pollution,'" explains Silver, one of the first to study marine snow. But the marine dustballs are bits of dead animals and plants and, as Silver describes it, "anything that's out there, all tumbled together." On these dustballs, tiny organisms live, eat and sometimes reproduce. The snow also serves as food for bigger creatures, such as fish.
     On the wall outside of Silver's laboratory hangs a magnified photo of a snow particle. Near it is a photo of ordinary dust, a bit of fluff scrounged from under a file cabinet or lab bench to make a comparison. The two dustballs look like siblings.

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