The Andros coral reef diorama

Andros Island, The Bahamas
Milstein Hall of Ocean Life

The Andros coral reef diorama is the only one of is kind in the world. Located in the museum’s Milstein Hall of Ocean Life, it depicts an actual site in the Caribbean: Andros cay and reef in the Bahamas. Viewers have a two- story perspective—a submarine view of the reef from the lower level of the hall, and a mezzanine-level view of the coral cay, Goat Island, and Andros Island breaking the waterline against a painted background of coconut palms and azure sky. It took twelve years and five separate expeditions to re-create this reef habitat that depicts thirty square feet of ocean floor. The story of the diorama’s creation is one of adventure and innovation.

In 1923, the museum sent curator Roy Waldo Miner to scout out a site for a diorama that would depict the amazing diversity of Life in a tropical coral reef. He chose Andros for its spectacular stands of elkhorn and staghorn coral, and its rich abundance of tropical fish. The collecting team brought back to New York City forty tons of coral—including a single specimen weighing two tons—and reassembled it in its original configuration. A six-ton welded steel armature supports the reconstructed reef.

The work was slow and tedious. In an era that pre-dated scuba diving, the artists and curators on the collecting expedition could not swim about freely. They descended to the sea floor wearing heavy diving helmets, weighted suits, and boots designed to keep them from floating to the surface, and they breathed air pumped through long hoses from a boat above.

Using traps, nets, and hand lines, the divers painstakingly brought each tropical fish specimen to the surface and placed it in an aquarium so a museum artist could paint a watercolor to capture its vivid colors in life. Then a plaster body mold was made of the fish to replicate the form and texture of each species. The collected fish specimens were then preserved in formaldehyde for future reference. A single expedition to the Andros reef produced molds for sixty-five different species of fish.

Back in New York, museum artists transformed this data into multiple casts of fish that would be depicted swimming through the reef habitat exhibit. Today these models would be made of fiberglass and plastic resins. Back then, each fish was cast in melted beeswax. Once cooled, the fish model was removed from its plaster mold, embellished with wax fins, and painted with oils, using the watercolor studies from the expedition as reference. The original beeswax models are still on exhibit in the Andros coral reef diorama today.

The work was so exacting that even the artist who painted the background of this diorama descended to the sea floor to capture the dappling and shimmering effects of light as it passes through deep water. Dressed in diving gear, Chris E. Olsen sketched the undersea world while underwater himself, using oil paints and a waterproof canvas stretched over a glass panel on a weighted easel.

The Andros coral reef was a vibrant ecosystem when this diorama was completed in 1935. Today, museum scientists would never consider removing any of its coral for educational display since coral disease outbreaks, sedimentation, overfishing, coral bleaching, and algal blooms have all contributed to its decline. Scientists in the museum’s Center for Biodiversity and Conservation are engaged in a long-term study of the Andros coral reef to better understand its condition and lead the effort to preserve and recover the reef. The diorama has provided valuable data in this endeavor by giving scientists a snapshot of Andros reef’s biodiversity during an earlier; more thriving time.