A MICROBIAL APPROACH TO REVEAL THE MECHANISMS ENABLING PROLIFERATION OF THE ISRAELI ROCKY SHORE REEF BUILDERS

Vermetid-reefs in the Mediterranean Sea and the rocky shore are hot-spots of biodiversity with economic and cultural importance for Israel national resources, setting them as the subtropical equivalent of coral reefs. The reefs depend for their existence on the actively-built rims constructed by several reef builders; among them are two species of intertidal Vermetid gastropods and the red Crustose Calcareous Alga (CCA), Neogoniolithon brassica-florida, yet their biogenic role is threatened by a rapidly changing environment. In order to recommend a protective strategy for these important natural resources for generations to come it is crucial to characterize these engineering species and their response to changes in environmental conditions.

Calcification by red algae creates an altered microenvironment potentially distinct in its microbial inhabitants. In addition, coralline-algae-associated-bacteria have been demonstrated to effect macro-scale processes extending beyond the limited magnitude of their niche. Here for the first time, the potential role played by CCA-associated microbial community was examined with respect to its survival in its natural habitat. We constructed a library of lab-cultured N. brassica-florida associated bacteria and developed tools to explore their localization and microenvironment, as a framework to address questions regarding what underlies its survival in the reefs and what are the metabolic and functional roles of this microbial consortium in this respect. We shall present several candidate strains bearing potential importance for these aspects and our current view on what limits this alga survival in the reefs. Identification of bacterial groups associated with this alga and their potential impact on its function will enhance our understanding of what determines its survival in the Vermetid-reefs for improved monitoring and preservation of these natural resources.