Analysis of the biodiversity of biofilm communities under in situ warming using heated settlement panels

Heated settlement panels were deployed for a period of 18 months in Ryder Bay near Rothera research station on the Antarctic Peninsula. The panels were set to heat a thin layer of water overlying the surface to 1°C or 2°C above ambient temperature, thus mimicking oceanic warming predictions in the natural environment and yet maintaining natural cycles of temperature variation, light regime, food supply etc. Using this heated settlement panel technology, Ashton et al (2017) reported the near doubling of growth rates of the bryozoan Fenestrulina rugula and a reduction in the overall species diversity and evenness in heated panels due to the spatial dominance of F. rugula. In this study, we analysed the biodiversity of biofilm communities from the Ashton et al., (2017) experiment, after a further period of 9 months in situ warming (total exposure of 18 months). Amplicon sequencing of bacterial 16S rRNA was used to evaluate the effects of a +1°C and +2°C temperature increase in the microbial composition of the benthic biofilm in the heated settlement panels, after an 18 month immersion at Rothera Research Station, Antarctica.