Structural characteristics of microbial biofilms in marine environment: colonization of macro-plastics deployed in the Ross Sea (Antarctica)

To date, microbial biofilm communities in Terra Nova Bay (Ross Sea, Antarctica)are still scarcely explored regarding their structure and function; moreover, no data are currently available regarding possible effects of environmental and/or anthropic forcing on microbial colonization. Funded by the Italian National Programme of Antarctic Research (PNRA16_00105), the project ANT-Biofilm started in November 2017 with the overall objective of studying microbial colonization of benthic environments, focusing on microbial abundance, activity and diversity, and larval settlement in response to natural or anthropogenic disturbances. Here we present the preliminary results on the structural characteristics and diversity of the microbial communities associated to two artificial substrates deployed in a coastal Antarctic environment of the Ross Sea, close to the Italian Research Station Mario Zucchelli. Polyethylene (PVC) panels and polyethylene (PE) coupons were placed at -5 and -20 m of depth in two sites in Terra Nova Bay (Road Bay and Tethys Bay, differently impacted by anthropic pressure) and collected after 3, 9 and 12 months during the 33 Italian Expedition. Bacterial community composition was studied at single cell level, by Catalysed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) combined with Confocal Laser Scanning Microscopy (CLSM). Moreover 16s rRNA gene sequencing was applied to compare the diversity of the planktonic and substrate-associated microbial communities.