LAGOON SPONGES FROM CARRIE BOW CAY (BELIZE): ECOLOGICAL BENEFITS OF SELECTIVE SEDIMENT INCORPORATION

Abstract

Sponges living in tropical lagoons on mobile substrata face many challenges. The most important requirement is stable anchoring allowing the sponge to grow with defined polarity. We determined the anchoring ability for thirteen common species in the lagoon of Carrie Bow Cay (Belize) by evaluating the type and amount of incorporated sediments and comparing them with the nearby substrate components. In the example of Tectitethya crypta, sediment is not merely utilised as substratum but serves also the sponge's structural organisation. Sand is transported into the body where it is organised in patterns that are determined by granulometry and sponge size. The transport is performed by an unusual type of cell characterized by its size (between 40 and 150 µm) and the presence of inclusions. Sediment incorporation processes strongly affect sponge ontogeny.