Calabash Caye, Turneffe Atoll, Belize (20 foot depth)

   Off the coast of Belize, Turneffe Atoll consists of over 150 islands and cays stretching 30 miles long and 10 wide. During the early 18th century, the pirate Blackbeard used the atoll as a base of operations while he harassed ships in the Western Caribbean. Now a marine reserve, Turneffe supports over 565 species of wildlife in habitats ranging from littoral forests to mangroves, seagrass beds, lagoon and coral reefs. 

   Reflecting diverse life in the reef shallows, the sand includes mollusc shells, spiral striped micromollusc snails and the delicate white bivalve at lower right. Sculptured green and tan sea urchin spines show the rounded base where each was attached by muscles to a ball on the urchin skeleton - like the fragment just left of center. The rod with the bumps is a fragment of a sea star or brittle star. Coralline algal remains include chalky white discs and triangles, see the kite-shaped one near center. Bright red grains are from the benthic foram Homotrema. There is a tubeworm casing, shaped like a backwards “J” at 8 o’clock.  

Base map public domain via Wikimedia Commons