Ecological interactions of marine sponges

Abstract

Sponges interact with most other organisms in marine systems as competitors, symbionts, hosts of symbionts, consumers, and prey. Considerable creative energy has been required to study and describe the amazing variety of sponge interactions, as sponges can hide symbionts deep inside, rapidly regenerate wounds from grazers, carry on important associations with unculturable microscopic organisms, and otherwise foil attempts to determine how they are interacting with other organisms. This review of sponge interactions covers (i) competition among sponge species, and between sponges and other sessile organisms; (ii) predation on sponges by sponge specialists and by opportunistic sponge feeders, and aspects of predation such as the importance of nutritional quality, trade-offs between growth and defense against predators, biogeographic patterns in predation, and the advantages of various techniques for studying predation; and (iii) symbiotic associations of sponges with a variety of organisms representing all types of life, and with results ranging from parasitism and disease to mutual benefit. A hint that some generalizations about ecological interactions of sponges may be possible is just becoming evident, as accumulating data appear to show taxonomic and geographic patterns; however, it is also clear that surprises will continue to emerge from every probing new study.