Giant barrel sponge

Photo: SiphonophoreSlinger · CC BY

Giant barrel sponges are the dominant structural organism on the Conception Island wall, some individuals reaching 1.5 metres in diameter and estimated to be over 2000 years old — they are sometimes called the 'redwoods of the reef.' They filter enormous volumes of seawater, playing a critical role in nutrient cycling. The intact population here is particularly notable as barrel sponges are vulnerable to bleaching events that have devastated populations elsewhere in the Bahamas.