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No. 93: May-Jun 1994

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Marine Snow

The marine analog of the high-altitude U2 used to collect interplanetary dust is the scuba diver armed with small jars and syringes. In these, marine biologists, such as A. Alldredge, collect the tiny bits of debris drifting downwards from the ocean's upper layers. This is the "marine snow." Its constituents are mainly:

"...the tiny leftovers of animals, plants, and non-living matter in the ocean's sun-suffused upper zones. Among these particles are chains of single-celled plants called diatoms, shreds of zooplankters' mucous food traps, soot, fecal pellets, dust motes, radioactive fallout, sand grains, pollen, and pollutants. Microorganisms also live inside and on top of these odd-shaped flakes."

Marine snow is everywhere in the ocean. Sometimes, it reaches blizzard proportions, and divers cannot see beyond a few feet. Measured in millimeters, the marine snowflakes are much larger than the average interplanetary dust particles (but of course interplanetary dust itself is also a constituent of marine snow). The bigger marine snowflakes -- over 0.5 mm -- are a major food source for deep-sea denizens waiting below for this manna from the watery heaven.

The reason for mentioning marine snow in Science Frontiers is that biologists like Alldredge are really pio-neering new territory, where new anomalies must surely dwell.

"'We've essentially discovered a whole new class of particles in the ocean that no one knew was there," she exults.


"'They're islands, really, where the metabolic activities of algae, bacteria, and protozoans produce unique chemical environments,' says Alldredge."

To illustrate, the carbon content of bacteria on marine snow is 10,000 times higher than that of bacteria found away from the snow. Why?

(Cox, Vic; "It's No Snow Job," Sea Frontiers, 40:42, March/April 1994.)

From Science Frontiers #93, MAY-JUN 1994. � 1994-2000 William R. Corliss