Cryptobiota associated to dead Acropora palmata (Scleractinia: Acroporidae) coral, Isla Grande, colombian Caribbean

Abstract

Cryptobiota of dead fragments of five branches in live position and five fallen pieces of the coral Acropora palmata each one of approximate 1dm3, covered by filamentous algae were extracted from the north reef crest of Isla Grande (Colombian Caribbean), in April 1991. There were three groups of organisms according to size and position (on and within the coral): 1) mobile epibenthos, mainly microcrustaceans that live among the filamentous algae 2) boring microcryptobiota, located in the layer between the epilithic organisms and the coral skeleton itself and, 3) perforating macrocryptobionts that bore and penetrate the coral skeleton. Polychaetes, sipunculids, mollusks and crustaceans were most abundant in the last group. There were no differences in macrocryptobiont composition between standing dead branches and fallen fragments. There was a large variation in total biomass and type and density of macrocryptobionts, possibly associated to stochastic factors such as placement and thickness of branches and small scale variations in recruitment.