114o F. General OI.R (1990) 37 02)

transformation has begun and this time it is one of reclamation inspired by the microbiologist and environmental philosopher Rent Dubos (d. 1982) who believed that natural beauty could be restored to a place if one would 'think globally' and 'act locally.' Now that philosophy has led to the creation of parklands in the bay (with local conservationists helping to clean up the area) and to the bay's incorporation into the Gateway National Recreation Area. The bay is responding and birds are returning. (wbg)

90:7279 Levine, J.S., 1990. For fish in schools togetherness is

the only ~'ay to go. Smit&~onian, 21(4):88-92.

For many species of fish, survival depends on cooperation which, in turn, involves schooling with others of the same species. Schooling enhances survival in two ways: it aids in feeding and in defense against being fed upon. Feeding is advanced when only a few find food and then alert others or when competitors are driven away from a food source by sheer force of numbers. As a means of defense, the advantage imparted by thronging together is not absolute as predators often use wolf-pack techniques to break up groups and split off strays, and schooling only works well during daytime. The communication upon which schooling seems to depend can involve sight, languages of clicks, grunts, and growls, and even electric pulsing. (wbg)

90:7280 Martin, Glen, 1990. Otter madness [environmental

engineers reshaping the California coast]. Dis- cover, 11(7):36-39.

With no insulating layer of blubber to protect against the cold North Pacific waters, sea otters developed a lush pelt for which they were hunted nearly to extinction. But aided by a 1911 treaty prohibiting international trading in their pelts and the U.S. Marine Mammal Protection Act of 1973, a state-protected band of California's otters is thriving. Along with the rebound in the number of otters, the northern Pacific kelp beds, which had been deci- mated by sea urchins, are thriving too. This is so because the otters consider the urchin a delicacy. The thick kelp beds, in turn, dampen wave action and slow subsurface currents, therefore creating a more well-balanced ecosystem. (wbg)

90:7281 Van Dyk, Jere and Natalie Fobes (photographer),

1990. Long journey of the Pacific salmon. Natn. geogr, 178(I):2-37.

Six of the seven species of Pacific salmon (excepting the steelhead) follow the same life cycle: hatching in rivers; travelling to sea; fattening at sea; returning to spawn in their birthplace (guided in part by smell); then dying. Although the development of dams has reduced the number of wild salmon by impeding their return to spawn (no more than 4 or 5 out of 3000 eggs laid by a female even reach spawning stage) millions still manage to accomplish the feat. Yet, the advance of civilization is taking its toll. About thirty per cent of salmon consumed today come from salmon farms, a fact often lamented by consumers, particularly the Japanese, who can taste the difference. (wbg)

90:7282 Ward, Fred, 1990. Florida's coral reefs are imperiled.

Natn. geogr, 178(I):114-132.

Appearances are sometimes deceiving, as they are in the case of coral reefs. Though rock-like to the senses, they are in actuality quite fragile living creatures that are easily damaged or killed, as is happening at a frightening pace in Florida. The establishment of John Pennekamp Coral Reef State Park in 1960 off Key Largo, instead of serving the cause of preservation, may in fact be adding to the problem of saving the coral reefs, which are damaged even by being touched or stepped upon by swimmers or divers. As if these insults to the coral were not enough, there is the problem of pollution brought on by onshore development and its atten- dant pesticide runoff, and nutrient loading of the water which promotes algae growth, all causing 'ecosystem dysfunction.' (wbg)

90:7283 Wickelgren, Ingrid, 1990. Simmering planet: com-

puter models are allowing geophysicists to see the unseeable--the roiling currents of hot rock in Earth's 1,800-mile-thick mantle. Discover, 11(7): 72-75.

Although plate tectonic concepts have provided explanations for many features at the Earth's surface, the mechanisms causing plate motion and convection are not well understood. A computer model developed by Gary Glatzmaier suggests that plates are pulled apart by their own weight as their cold, dense leading edges sink into the mantle; midocean ridges are secondary features created by the rise of hot rock into the gap left by the sinking plates. A model developed by Peter Olson also recognizes the importance of sinking currents, which descend from the surface through the mantle. A third model by John Baumgardner indicates a density boundary within the mantle which slows the descent of sinking plates. In contrast, a fourth model