By Jim Smith

Half a mile southeast of Bermuda’s Castle Harbor, Gurnet Rock rises, unexpectedly, from the cerulean ocean. Nesting site for the endangered Bermuda petrel— a bird once thought to be extinct, but which was rediscovered in 1906—it’s well protected from visitors. Not that many would visit. Gurnet’s near-perpendicular shoulders discourage landing. And besides the petrels, Gurnet nurtures precious little else.

Beneath the surface, however, it’s a different world entirely. The warm, tropical water is astonishingly clear and supports dense populations of brilliantly colored fish. Profuse gardens of seaweed undulate gently. The experience of diving there, says Charles A. Dana Professor of Biology Craig Schneider, is “like swimming in an aquarium.”

Sixty-five feet down, one day last February, Schneider and Chris Lane ’99—Schneider’s former student and now, with a new Ph.D., his colleague as well—were so intent upon the plants that they were completely oblivious to a 60-foot humpback whale languishing above. The two men were searching for a red alga named Platoma cyclocolpum. Last reported near Gurnet in 1917, it hadn’t been seen anywhere in the islands for years. Many scientists speculated it was locally extinct, but Schneider was unwilling to accept that conclusion.

A veteran of 5,000 dives

One of the world’s leading experts on benthic marine algae, plants that grow on the floor of the ocean, and especially the algae whose homes are Bermuda and the continental shelf off the southeastern coast of the U.S., he’s also a veteran diver. He has more than 5,000 dives to his credit, including many at extreme depth.

Schneider had never seen Platoma and he didn’t know a biologist who had. But he knew it was a winter inhabitant of Bermudian waters and this was not only the first time he had explored there in the winter, it was the first time any biologist intent upon cataloguing indigenous algae had done so offshore. “I believed the Bermuda plants were genetically distinct from the Mediterranean populations, where Platoma was originally described,” he says, and with Lane’s experience in DNA analysis he hoped to prove the point with newly collected material.

Both men were surprised, and more than a little gratified when, within minutes after saying goodbye to their guide and dropping over the side of his small boat, they discovered the plant. They found it so quickly, indeed, that they had plenty of air left to look for other specimens. And over the two weeks they dove in Bermuda last winter, they discovered new species, as well as others already recognized as new to science, but not yet published; plants they had already found elsewhere in the islands.

“The term ‘biodiversity,’ meaning the study of biological diversity in the world’s varied ecosystems, graces our daily news with increasingly frequency,” Schneider says. “Taxonomists define the biodiversity of an area, and ecologists assess relationships of the flora and fauna with the physical and biological environment. Ecologists have discovered that the life found in an environment is often indicative of environmental quality. That’s a concept everyone can appreciate. But without proper taxonomic studies in a given region—the knowledge of exactly what species are present—conclusions and comparisons with other regions or environments can be flawed. Worse, they can be misleading.”

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