Microbial response to environmental change in a marine benthic system

Marine sediments are important sites for global biogeochemical cycling, and whilst the presence of macrofauna and microalgae mediate these processes, the recycling is driven by microbial activity. There is strong evidence that coastal benthic habitats will be affected by changing environmental variables characterized by rising temperature and elevated CO2, and research has focused on the impact on macrofauna and ecosystem services, such as nutrient cycling. However, despite their importance, there is limited understanding of how alterations in microbial assemblages will influence these key processes. Using an experimental mesocosm approach, cutting-edge molecular techniques were used to identify changes in the microbial community in response to manipulated environmental conditions (temperature, CO2). Illumina sequencing of the bacterial community composition generated over 11 million 16S rRNA gene sequences. These results were correlated to simulated environmental conditions using canonical correspondence analysis (CCA) and showed that at the species level, community composition was influenced by changes in the mean temperature, with CO2 and temperature variation having no significant effect. The results suggest that the role of bacteria in sediment may be significantly altered, with implications for biogeochemical cycling in future climate change scenarios.