National Geographic : 1972 Aug
Undersea farmer, author Wheeler North has spent more than a decade studying and restor ing California's depleted kelp beds. Quicklim ing urchin-infested areas, he then transplanted mature kelp, towing it from miles away. He also set up a seaweed nursery ashore to cultivate kelp spores by the billions. Flanked by culture tanks, Dr. North prepares a microscope slide. Spores placed in the tanks become male and female gametophytes (1). They produce eggs and sperm that combine to form the embryonic zygote (2), which soon develops into a minute kelp plant (3). The new generation is then scattered on the sea bottom. Urchin-smashing diver (lower right) helps assure that enough plants mature-one in 100,000-to reestablish the beds.