Whilst exploring our geological collection in preparation for Sea Finds: a Hands on History session looking at objects related to the sea, I found a brain coral. I can’t say that I particularly like this object as its brain-like appearance discomforts me but it truly is an ocean find with a fascinating life story.
Composed of limestone compacted into a stony exoskeleton, brain corals grow very slowly with each generation adding to the limestone skeleton. Amazingly, they can live up to 900 years. Their big, strong structures form the foundation of coral reefs; colonies of brain corals can reach up to six feet tall.
Despite their rock-like appearance, brain corals are actually animals with living parts called polyps. The bodily form of a polyp is a soft fleshy tube with tentacles surrounding the mouth. Individual polyps look much like tiny anemones. Polyps excrete the limestone which forms the stony non-living part of the coral. The limestone skeleton of the polyp remains after its death and each generation of polyps continues to add to the structure. Polyps stay permanently stationary, feeding on miniscule organisms that float past them called zooplankton and the algae that live among them provide them with oxygen.
Brain corals are invertebrates related to anemones and jellyfish. They live in the Caribbean Sea and the Atlantic and Pacific Oceans. Most coral reefs grow in tropical or subtropical water. Brain corals ideally prefer clear, shallow water that sunlight can permeate.
Drop in between 11 am and 4 pm on Saturday 19 January to handle sea-related objects with our Access Assistants.