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Finding coffee beans a perk for divers

Some coffee beans are good for brewing, others are best for viewing. Finding the latter beans, actually marine snails, requires both scuba equipment and luck. It seems ironic that something, well, sluggish shares a name with something known for its stimulant properties. However, the moniker has nothing to do with behavior and everything to do with similarity in shape, size and color. Pusula solandri, a local coffee bean species, has an oval, purple-brown shell less than an inch long. Raised, spiral ribs originate along the central slit found on the shell’s underside and curve upward where they end at the midline of the shell’s topside.

I rarely see coffee beans on my dives in the La Jolla Ecological Reserve but when I do, the bean’s shell is usually well hidden by the body’s fleshy extension. Called a mantle, it is responsible for secreting the shell and maintaining its pristine condition. Once the two sides of the mantle slide up over the shell, potential squatters can’t set up house. As such, the glossy shell remains hitchhiker free when periodically revealed. During travel, a coffee bean displays its pair of head tentacles, which protrude from beneath the body. I can barely make out ebony dots that denote the eyes. Above the head juts a unicorn-like siphon, the proboscis. The tubular structure comprises a feeding and sucking apparatus, the jaws and sandpapery tongue being placed at its tip.

Colonial tunicates are the prey of choice for coffee beans. A tunicate colony is made up of minuscule filter-feeding individuals with saclike bodies. As a group, a tunicate population may encrust rock or sediment surfaces, appearing as irregularly shaped patches with varied textures. Depending on tunicate species, colony pigmentation covers the spectrum from bland to flamboyant. It is a tunicate’s color that determines the coffee bean’s hue as that pigment is passed along to the grazing bean’s soft tissue. Being matchy-matchy with a tunicate ties into a coffee bean’s reproduction strategy. The spawn deposited onto the colony by coffee bean couples is undistinguishable from the tunicate in both color and globular shape. It takes more than a wing and a prayer to find such an egg mass.

Like most of the ocean, little is known about a coffee bean’s role in its environment. Over the past 50 years, since the beginning of the “space race,” federal budget resources have concentrated on understanding outer space. Interestingly, while the solar system remains essentially unchanged in the last half century, we have dramatically altered our ocean by overfishing, polluting, destroying habitat and changing the climate. How is it we didn’t first choose to invest in a comprehensive study of the ocean? Without knowing what was, we can only create new “normals” after any crisis. Each day we make choices that impact the ocean’s health from, letting the car idle while chatting on the phone to requesting a plastic bag when purchasing one or two items. It’s time we wake up and smell the (sustainably grown) coffee.

— Judith Lea Garfield, naturalist and underwater photographer, has authored two natural history books about the underwater park off La Jolla Cove and La Jolla Shores. Send comments to