Does zoning affect the distribution and abundance of sponge growth forms on corals reefs of the Great Barrier Reef?

Sponges are the simplest metazoans and these efficient filter-feeders are found in most marine environments, including coral reefs. Identifying sponges to species is difficult and time consuming requiring tedious microscopic... [ view full abstract ]

Sponges are the simplest metazoans and these efficient filter-feeders are found in most marine environments, including coral reefs. Identifying sponges to species is difficult and time consuming requiring tedious microscopic identification techniques. The use of growth form features however, can help to identify some important characteristics of their environment. Sponge structure, abundance and distribution are determined by various biophysical factors including: water flow, depth, temperature, light, sedimentation, competition, currents, larval dispersal and recruitment patterns, substrate and habitat type and various physical forces. However we question, “Does zonation and protected area status affect the abundance and distribution of sponges in relation to these biophysical factors?” This study aimed to improve the classification of sponges to growth forms by reanalysing images of sponges from a long-term dataset on the rezoning of coral reefs of the Great Barrier Reef Marine Park. We also examined whether protected area status of a reef affected the abundance and distribution of sponges on the Great Barrier Reef. The most abundant growth forms were encrusting forms, followed by upright and cup-like forms. Geographical Information Systems (GIS) were used to analyse how abundance and distribution of sponge growth forms varied across spatial scales with biophysical parameters such as temperature, currents, chlorophyll a, and marine park zoning.