Acropora palmata stony coral rubble colonization by lithifying biofilms indicates a significant change in associated genetic diversity, which is not affected by projected increases in water oceanic water temperature.. Microbial composition of biofilms associated to lithifying rubbles of Acropora palmata branches

Coral reefs are amongst the most productive ecosystems on the planet, but are rapidly declining due to global warming mediated changes in the oceans. Particularly for the Caribbean region, Acropora sp. stony corals have lost ~80% of their original coverage, resulting in vast extensions of dead coral rubble. We analyzed the microbial composition of biofilms that colonize and lithify dead A. palmata rubbles in the Mexican Caribbean and identify the microbial assemblages that can persist under scenarios of global change, including high temperature and low pH. In situ samples from the Puerto Morelos reef and lab-scale mesocosms were analyzed using 16S rRNA gene sequencing. Lithifying biofilms were uniquely different in microbial composition in comparison to surrounding sediments, microbial mats and healthy A. palmata microbiome. Significant shifts in microbial community composition were detected in samples incubated in mesocosms after seven days and in low pH. Biofilm communities that lithify dead A. palmata rubbles were apparently resistant to expected changes in ocean water temperature but not for decreases in pH. Our findings suggest that these biofilms will be more prominent with time, thus consequently impacting the functional role of coral reefs.