Two of the most arresting bulletins gathered in this brief but compelling report on the world's oceans come from the eternal night of the sea floor. The first is the discovery of a new kind of ecosystem in the great rifts that function as escape valves for molten material inside the earth. The effluent is laden with hydrogen sulfide, which certain bacteria convert into usable energy. The bacteria, in turn, nourish clams, mussels, crabs and sea worms. The whole constitutes "the only known ecosystem independent of sunlight for its food supply."

The other news concerns the longevity of oil slicks. Until recently it had been assumed that once a slick dissipated, the danger of contamination was over. Scientists at the Marine Biological Laboratory in Woods Hole, Mass., have learned, however, that oil can oxidize in sunlight, a transformation that renders it both harder to see and more toxic. It can also end up on the sea floor in the excreta of zooplankton; there it kills higher forms of life and makes room for lower ones.

But Anne Simon, who has written previous books on islands and the seacoast, is not content to leave odd maritime facts in her wake. Her purpose is polemical, and in a follow-up chapter she rebukes those who palm off oil spills as accidents. Rather, she argues, they amount to an inevitable "earth tax which the nation . . . appears willing to pay . . . a choice made by the body politic, believing the ocean can take it, indeed must take it for the sake of oil."

Simon's rhetoric notwithstanding, oil spills do seem unintentional in contrast with other, chronic abuses of the ocean. Take the dumping of wastes: raw sewage, DDT, PCB, even "radwaste" (as low-level radioactive waste is called). Or consider the Navy's proposal to scuttle Trident submarines, still equipped with radioactive reactor compartments, at sea. The decision-makers who pursue these policies bear the ocean no ill will. They simply operate on the flimsy assumption that it can contain all this detritus safely.

Commercial fisherman also mistreat the ocean and its resources; during this century the global roster of fisheries has steadily declined. One victim was the Pacific sardine, raw material for John Steinbeck's "Cannery Row" but defunct as a harvestable resource since 1967. Another was the anchoveta, object of the world's largest fishery, off the coast of Peru. Although conservationists twice proposed a limit of 9.5 million tons of anchovetas a year, fishermen rejected it and hauled on. By 1980 the catch had dwindled to less than 1 million tons a year.

Someday the sea may also serve mankind in a new and unexpected role: disposal for carbon dioxide. Citing the gas' well-known capacity to block the escape of solar radiation into outer space, Simon notes that "without CO2 in the atmosphere, the ocean would freeze; with too much CO2, it would boil itself away." In recent decades, powered by the burning of fossil fuels, the CO2 level in the atmosphere has risen so much that, experts predict, by the year 2050 the "greenhouse effect" will cause the worldwide temperature to rise between 2.7 and 8.1 degrees Fahrenheit. Such an increase could melt the polar ice caps, swell the seas and flood coasts all over the planet.

There is some evidence, however, that the deep ocean can absorb great quantities of CO2. Simon argues for cutting back drastically on the release of CO2 into the atmosphere while we study the feasibility of submerging it at the bottom of the sea.

Is Simon's case for a radical reformation of our oceanic behavior -- complete with a U.S. ocean czar to coordinate policy -- convincing? To me it seems thoroughly researched, cogent, forceful but not strident. But doubtless some Ben Wattenberg with a diving bell is working full speed ahead on a rebuttal. When it surfaces, we can make the comparison.

In the meantime, we might recall a point made by the late Barbara Ward: "One of the profound problems posed by nature's 'thresholds' is that the approach to the point of no return may give few if any danger signals. Red lights do not flash on in the deeps as one more species -- of whose role in the total ecosystem we are completely ignorant -- heads for death." And to put the matter in Anne Simon's myth-borrowing terms, once Neptune has been pushed too far, his revenge may be catastrophic.