Macroalgal assemblages on dead surfaces of scleractinian corals (Anthozoa: Scleractinia) in the Oro Verde reef, Veracruz, Mexico

Abstract

Benthic macroalgae are abundant in the Oro Verde reef but their taxonomic richness was hitherto unknown and it is presumed to present settlements on the massive corals. For this reason, the present workinvestigated which species of massive corals show algal colonization. Also, their taxonomic composition wasdetermined, and the similarity of the algal assemblages between species of scleractinian corals was measured. Tensampling points were systematically established in the reef, where a transect band of 50 x 2 m at each site wasplaced to locate and collect algae fron the dead surfaces of scleractinian corals. The frequency of occurrence ofalgae species was estimated based on the total number of coral species studied, as well as on each coral species.Similarity and ordination analysis were applied in order to explain similarities and significant differences of thephycological composition among the coral species. Scleractinian corals with algal assemblages were: Siderastreasiderea, Montastraea cavernosa, Pseudodiploria strigosa, Colpophylia natans, Stephanocoenia intersepta, Porites astreoides, Orbicella annularis, Orbicella faveolata. Thirty-two species of algae were identified from a total of100 revised coral colonies which are represented in 3 divisions, 10 orders and 15 families. The corticated, foliosecorticated and filamentous macroalgae were the most represented species. The most frequent algae on massive corals were Laurencia obtusa, Amphiroa rigida and Caulerpa chemnitzia. Massive corals with higher algal recordswere S. siderea (9 species), M. cavernosa (19 species) and P. strigosa (17 species). The algal assemblages on themassive corals presented low similarity. However, no significant dissimilar groups were detected. Only S. sidereaand M. cavernosa are relatively similar in phycological composition. The results suggest that the massive coralsof the Oro Verde reef are vulnerable to the colonization of algae, but it is necessary to investigate the conditionspreceding algal settlement.