This year, when the U.S. Army Corps of Engineers diverts the Cooper River in South Carolina into the Santee River, scientists expect that the marine life in the Santee will change and that the estuary could become a unique classroom for scientific research.

About 200 miles north, along the North Carolina coast, the Ten Fathom Ledge has become a popular scuba diving area because of unique reefs, coral formations and a World War II submarine wreck. But the site has also been included in the Outer Continental Shelf tracts where companies can explore for oil and gas.

These and 80 other coastal areas are being reviewed by eight teams of scientists under contract to the government who will choose up to 40 that are the most worthy of protection as National Marine Sanctuaries.

By mid-February, the top candidates will be forwarded to the National Oceanic and Atmospheric Administration's sanctuary programs division. Over the next few years, NOAA plans to pluck two or three from the scientists' list each year for a more intensive review and public hearings that normally lead to sanctuary status.

Marine sanctuaries are a relatively new federal designation. Since 1972, six have been designated: the wreck of the Civil War-era USS Monitor off the coast of North Carolina, two coral reefs in the Florida keys, two areas off the California coast, one covering the Northern Channel and Santa Barbara islands and another covering the waters off Point Reyes and the Farallon Islands, and Gray's Reef off the coast of Georgia.

In some ways, the "sanctuary" moniker overstates the protection the areas enjoy. Each is protected from specific threats that are spelled out in its management plan. For example, the Monitor site is protected from salvage operations and the waters around the California islands, from oil exploration. It is the Coast Guard's job to enforce the restrictions.

The first six sanctuaries received that designation under emergency circumstances. The current review is designed to study systematically all potential sanctuaries and to decide which should be protected first, if at all.

That does not mean NOAA will not move quickly if it has to. "If the Pinta [one of Christopher Columbus's ships] were found, we'd designate a sanctuary to protect it," said Dallas Miner, who heads the NOAA office.

In the current review, the public has had the opportunity to nominate sanctuaries that the scientific teams did not plan to study. The only local area under study, a proposed "Virginia-Maryland Nearshore Waters and Barrier Island Bay National Marine Sanctuary" was one of those, nominated by the Committee to Preserve Assateague Island Inc.

The 1,200-square-mile area, one of nine under study in the North Atlantic, is being reviewed to determine whether the large recreational and commercial fishing industry there needs protection. The Assateague committee said it was concerned about threats to the underwater grasses that make the area an excellent spawning ground for fish.

While the Maryland and the Virginia Council on the Environment support the designation, it has been opposed unanimously by the boards of Northampton and Accomack counties on Virginia's Eastern Shore. "It is our considered opinion that it would serve no useful purpose," wrote C.M. Williams Jr., Accomack County administrator. "It would only be redundant and generate additional expense to the government."

In any case, the tract's chances do not look good at this time. Although a preliminary report said its "wetlands are biologically rich and diverse, support numerous marine organisms and form a primary part of this region's ecosystem," Miner said he does not think there are "enough marine resources that need protection at this time." If the sanctuary survives the first cut, Miner said, he would recommend against advancing the proposal.

Later this year, NOAA plans to move ahead on designating two sanctuaries that were not part of the current review: La Parguera, off the coast of Puerto Rico, and Fagattle Bay, off the coast of American Samoa. In 1984, the agency wants to designate a humpback whale sanctuary among the Hawaiian islands and then begin picking from the list that is now under review.