A NATIVE MARYLANDER, Nick Caloyianias did deep-water filming for decades, working in oceans around the world before refocusing his energies in recent years on his home waters: the Chesapeake Bay, a shallow-water estuary that presents a different set of challenges for an underwater photographer.

I first hired Caloyianis and his partner Clarita Berger more than 30 years ago, asking them to dive down and film the Bay's dwindling seagrass beds for a Maryland Sea Grant documentary called Chesapeake: The Twilight Estuary. Since then he and Berger have filmed in the waters around Galapagos, the Greek Islands, the Red Sea, the North Atlantic, the Arctic, the Caribbean, and the far-western Pacific. When Caloyianis began working again in the Chesapeake Bay, he provided vital underwater footage of oyster reefs for another Sea Grant documentary, Who Killed Crassostrea Virginica? He also serves now as cameraman and director of photography on broadcast projects for Maryland Public Television.

With his experience and long-term interest in marine science, Caloyianis has transformed himself into an unusual kind of naturalist, an underwater naturalist. The definition of naturalist always been appropriate for certain nonscientists, including writers like the famous Henry David Thoreau and the less famous Gilbert Klingel. Back in 1951, Klingel wrote The Bay, one of the first popular books on the Chesapeake Bay. The writer, it turns out, is an inspiration Caloyianis likes to cite, not just for his book, but for his early interest in directly observing the underwater life of the estuary. Klingel spent time on the bottom in old-style diving suits with metal helmets and in a diving bell he invented himself. He brought back some of the first photographs of the underwater Chesapeake.

In recent years Caloyianis has been trekking out with all his scuba and camera gear to film and photograph key species in the Bay, both the famous and the little known. Not just blue crabs and oysters and striped bass, but red sponges and toadfish and killifish, all shown in the underwater world where they live, a world the rest of us — including most scientists — never see. His goal is a book he's titled Life Beneath the Chesapeake. He sees it as "a big-picture look" at the underwater estuary: full of color photos that would give — species by species — a view of the whole system. He's after "the quintessential elements that made the Chesapeake what it is."

Caloyianis has better gear than Klingel ever had, but he's got a bigger problem to solve. The key to great photography is light, and light is hard to come by in the Chesapeake Bay, much harder than it was when Klingel made dives in the mid-1950s or when Caloyianis himself first began diving and photographing in the mid-1970s. As a beginning photographer, he worked for two years as a commercial oyster diver. "I didn't make that much money," he said, "but I saw a whole lot. And every chance at good visibility I took my camera in the water." Down along the bottom of the Choptank River he made pictures showing 20 to 25 feet of visibility. "Look how clear the water was," Caloyianis said, pointing to a photo he made of Berger. "We haven't seen that in a quarter of a century."

He has also learned some helpful tricks over the years. One key trick has been to always bring lights. Another is to pick his spots — two favorites are Eastern Bay and Mobjack Bay — and pick his days. He checks the marine weather reports, especially the wind reports, and pulls up the latest satellite imagery that can show an educated eye a lot about current turbidity patterns.

He may soon have another trick to try. Caloyianis seems to have inherited Klingel's inventor gene. To work around the murky water problem, he's been helping create and test a camera system designed for photographing oysters in zero-visibility waters. It's a project supported by the Chesapeake Bay Foundation to help solve the problem of monitoring their oyster restoration sites.

When the “ClearWaterBox” had its recent baptism in the Bay waters near Baltimore, the initial results "astounded" Bill Goldsborough, the recently retired senior fisheries biologist for the Foundation who helped start up the project. The box was tested as an underwater photogrammetric tool that could be used to show the “before” and “after” conditions on a newly created site for oyster restoration.

It's not an easy tool to use. For the test Caloyianis was diving "in dark pea soup conditions" and found himself wrestling with a box that behaved like a sail in the current. The results, however, offer hope for perfecting a tool that will provide more accurate data on the status of oyster restoration in Chesapeake Bay.