Dark spires and archways rise from the sheer dolerite cliffs of the Tasman Peninsula, a rugged contrast to the Tasman Sea’s glassy surface below. The calm conditions are unusual for this chunk of earth perched on the edge of the Southern Ocean and the Roaring Forties.

As the dive boat nears Cape Hauy, I lean over the side to see the sunlight dance and fracture in the clear blue water. Aside from the lazy Australian fur seals that seem in no rush to haul off the rocks and join me in the chilly water, I couldn’t have asked for better conditions.

Tasmania is an island of contrasts, scenic one minute and harsh the next. The rugged coastline served as a natural fortress for Britain’s penal colonies; not a single convict is known to have escaped from the island. The formidable black coast, where the waters of the vast Southern Ocean meet the Tasman Sea, claimed the lives of convicts and sailors alike.

But the Tasman Sea has another side, one of rich and sometimes strange life coaxed from the depths by its nutrient and oxygen rich waters. This sea, so masterfully photographed by David Doubilet, has one of the highest rates of endemism of any temperate waters.