Summary of Abstract Submission

Abstract Submission No. IO50-09-0052PresentationPoster

GEOGRAPHIC VARIATION OF BACTERIA ASSOCIATED WITH SPONGE, SIGMADOCIA FIBULATA FROM THE CORAL REEFS OF INDIAN OCEAN

Subina N. S,*1, Annie Feby1, Maria-Judith Gonsalves1, Shanta Nair1

1 CSIR-NATIONAL INSTITUTE OF OCEANOGRAPHY,GOA, INDIA

ABSTRACT :

Coral reefs are tropical shallow water ecosystems which are the most biologically productive and diverse of all natural ecosystems. In this study, the demosponge, Sigmadocia fibulata was collected from coral reef Islands, Kavaratti, west coast of India and from Gulf of Mannar, east coast of India. Physical parameters were higher in Kavaratti (p<0.001) whereas nutrients (p<0.001) were higher in Gulf of Mannar. Bacterial abundance ranged from 1.42 0.42x107 g-1 and 3.220.42x107 g-1 in Gulf of Mannar and Kavaratti respectively. α-Proteobacteria (63%) and γ-Proteobacteria (66%) were the dominant phylogenetic group in the sponge associated culturable bacteria from Gulf of Mannar and Kavaratti, respectively followed by Firmicutes and Actinobacteria. Bacteroidetes were present only in sponge from Gulf of Mannar. Ruegeria was the dominant bacterial genera in sponge from Gulf of Mannar, whereas, Vibrio was the dominant genera in sponge from Kavaratti. Species richness and evenness were higher in sponge from Gulf of Mannar. DGGE showed 7 bacterial phyla in S.fibulata from Gulf of Mannar such as Cyanobacteria, Spirochaetes, Firmicutes, Chloroflexi, Acidobacteria, Actinobacteria and Proteobacteria whereas S. fibulata from Kavaratti did not harbour Spirochaetes and Chloroflexi. Firmicutes was the dominant phylum in S. fibulata from both the locations followed by Proteobacteria. This study reports geographic variation of bacteria associated with sponge, S. fibulata. The differed pattern of bacterial distribution in sponge suggests that sponge has a specific mechanism of symbiont selection, influenced by the variation in environmental variables, filtration of bacterioplanktons from the surrounding water besides vertical transmission.