The intensifying tanker war in the Persian Gulf is threatening that region with serious environmental damage. Environmental analysts say that the possibility of major oil spills - made more likely by the recent mining of commercial shipping lanes - compounds the danger already posed by other sources of oil pollution.
The Gulf supports biologically rich coral reefs as well as several species of sea turtles and the dugong, a rare marine mammal.
The marine environment is also crucial to the economies of nations on the Gulf. It provides both fishery resources and water which is desalinated for drinking.
On Aug. 10, the United States-owned tanker Texaco Caribbean hit a mine in the Gulf of Oman, dumping more than 1 million gallons of crude oil. Although the blast occurred outside the Persian Gulf, experts say it illustrates the vulnerability of oil-laden ships throughout the region.
``Mines hit just below the water line, where they are more likely to rupture tanks,'' says Richard Golob, executive editor of the Oil Spill Intelligence Report, a Cambridge, Mass. publication that tracks oil accidents worldwide.
Since oil is lighter than water, a ruptured tank quickly empties as the petroleum flows out in a thin layer onto the sea.
``If one of today's supertankers gets just three cargo holds ruptured,'' says Mr. Golob, ``you could have a spill larger than the Argo Merchant.''
The Argo Merchant spilled 7.5 million gallons of oil off the coast of New England in 1976 - the worst oil spill in US history.
So far only a small fraction of the oil dumped into the Persian Gulf has been caused by attacks on tankers. Other sources include coastal refineries, offshore drilling, and natural seepage through the ocean floor. Attacks like those over the weekend on Iran's Kharg Island oil terminal and other offshore facilities also contribute to the pollution of the Gulf.
The National Academy of Sciences estimates that about one-fifth of the oil that goes into the world's oceans comes from routine tanker operations, such as the release of ballast water contaminated with oil.
``Every new spill adds to the total,'' says John Hardy, a senior research scientist at the Battelle Northwest Marine Research Laboratory in Seattle. Since the Gulf is relatively shallow and enclosed, he says, the effects of a major spill could be magnified.
However, the Persian Gulf has also proven to be quite resilient.
``The effects of petroleum tend to be less in tropical or semi-tropical climates than in cooler areas,'' Dr. Hardy says.
Heat and sunlight speed the breakdown and evaporation of oil, particularly the volatile elements which are the most toxic to marine life.
Studies conducted on coral reefs off the coast of Saudi Arabia have shown that damage is minimized when oil contamination occurs in the summer, rather than in the winter. In addition, Gulf waters are flushed into the much larger Indian Ocean relatively quickly.
David Ross, chairman of the geology and geophysics department at Woods Hole Oceanographic Institution in Woods Hole, Mass., says this flushing action helps, but it does nothing for oil that sinks to the bottom.
Oil that sinks quickly tends to carry more of its toxic elements along with it. This can be especially damaging if the spill occurs in estuaries or other environmentally sensitive areas.
``We really don't know what the long-term effects [of submerged oil] on marine life will be,'' says Dr. Ross.
Each oil spill acts differently, he says, depending on currents and weather conditions. It often takes years before solid conclusions can be reached. And even then, the region requires steady monitoring by scientists.
``The Persian Gulf has had a considerable amount of pollution stress,'' Ross says,``but nobody's really watching it.''
To ease the danger, oil companies have developed elaborate methods to fight spills. Special equipment is available to scoop oil from the surface of the water, while chemicals can be used to speed the breakdown of the oil itself.
But such technology can become irrelevant in a war zone.
In 1983, Iraqi missiles blasted several of Iran's off-shore oil wells, causing the worst oil spill in the region's history. Repair crews that tried to cap the spewing wells were shelled, and it took months before the leaks could be stopped. Experts still aren't sure how much oil was dumped.
Indeed, the seven-year-old Iran-Iraq War has stymied several efforts at regional cooperation to deal with ocean pollution.
``Accomplishing anything on a Gulf-wide basis is difficult,'' Golob says. That was true even before the fighting started, he adds.
In the late 1970s, for example, the United Nations set up an environmental planning program in the region. But a dispute quickly emerged over what to call the plan.
The Iranians insisted it be dubbed the ``Persian Gulf Action Plan,'' while Arab nations argued for the ``Arabian Gulf Action Plan.''
In the end, it became the ``Kuwait Action Plan,'' named by default after the place where the negotiations took place.