The Fertile Sea

Many of the earliest humans lived on sea food, picking up clams and oysters. Later, man largely deserted the sea as a source of food. Now, with the land filling up with people, the sea looks good again. In Agricultural and Food Chemistry. Dr. Francis Joseph Weiss, Austrian-born chemist, tells how man might harvest the sea's bumper crops.

On the average, says Dr. Weiss, an acre of sea grows nearly three times as much plant material as an acre of land. Nearly all sea-growing plants are microscopic phytoplankton (mainly diatoms and dinoflagellates) that form the broad base of a "food pyramid." They are eaten by slightly bigger zooplahkton, and these small grazers are processed in the stomachs of bigger and bigger carhivora. The food in the original plants diminishes by nine-tenths at each eating. So when a human fisherman catches a fine codfish, each pound of its flesh represents about 100,000 lbs. of plants that grew in the sea. This process is wasteful, thinks Dr. Weiss. Man would do better to harvest the lower, broader stages of the food pyramid.

The phytoplankton is probably too small, but great whales gather the zooplankton, and man should be able to do the same. Dr. Weiss quotes a British opinion that two fishermen with suitable nets could catch about 600 Ibs. of zooplankton a day off the coast of Scotland. The stuff is a paste with a delicate shrimpy flavor.

Some of the small carnivora feed near the surface at night and retire during the daytime to a lower level where they can be spotted by echo-sounding devices. Dr. Weiss believes that special vessels could drop flexible hoses into these living strata and suck up enormous quantities of edible zooplankton.

Man must also learn, says Chemist Weiss, to preserve this new and perishable crop. A science of marine chemistry is developing rapidly to do the job by dehydration or chemical treatment. Already many fish products, e.g., fish flour and fish concentrates, are being made imperishable enough to be shipped to any part of the world. But even if all the world were to live on such stuff exclusively, they would never make a dent in the 135 billion tons of carbon (equivalent to 350 billion tons of starch) that is fixed every year in the fertile fields of the sea.

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