Benthic Community and Nutrient Enrichment Influence Development of Reef Biofilms

Shifts in reef benthic communities from calcifiers to fleshy algae have been documented on reefs world wide. While it is well established that these phase-shifts have severe consequences for ecosystem services, the impacts of shifting benthic structure on reef microbial ecology is an area of active research. To investigate the response of microbial communities to increases in inorganic nutrients, we subjected three dominant reef constituents; 1) corals, 2) macroalgae, and 3) sand to two levels of nitrate and phosphate over 6 weeks. We collected planktonic and surface attached microbial communities at three time points; using 16S rRNA sequences we investigate the effects of inorganic nutrients and reef constituents on the development of marine biofilms over time. We found biofilm communities were distinct from planktonic microbial communities throughout the duration of the experiment. Further, biofilm communities exhibit strong successional patterns and were significantly influenced by both, benthic constituent and nutrient amendments across all time points. Our results show that benthic community and nutrient enrichment significantly impact the development of marine biofilms and advance the understanding of microbial community structure across varying reef environments.