Extreme weather events as an important factor for the evolution of plastisphere but not for the degradation processExtreme weather events as an important factor for the evolution of plastisphere but not for the degradation process Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2025-03-212023enMarine plastics, with their negative effects on marine life and the human health, have been recently recognized as a new niche for the colonization and development of marine biofilms. Members of the colonizing communities could possess the potential for plastic biodegradation. Thus, there is an urgent need to characterize these complex and geographically variable communities and elucidate the functionalities. In this work, we characterize the fungal and bacterial colonizers of 5 types of plastic films (High Density Polyethylene, Low Density Polyethylene, Polypropylene, Polystyrene and Polyethylene Terepthalate) over the course of a 242-day incubation in the south-eastern Mediterranean and relate them to the chemical changes observed on the surface of the samples via ATR-FTIR. The 16s rRNA and ITS2 ribosomal regions of the plastisphere communities were sequenced on four time points (35, 152, 202 and 242 days). The selection of the time points was dictated by the occurrence of a severe storm which removed biological fouling from the surface of the samples and initiated a second colonization period. The bacterial communities, dominated by Proteobacteria and Bacteroidetes, were the most variable and diverse. Fungal communities, characterized mainly by the presence of Ascomycota, were not significantly affected by the storm. Neither bacterial nor fungal community structure were related to the polymer type acting as substrate, while the surface of the plastic samples underwent weathering of oscillating degrees with time. This work examines the long-term development of Mediterranean epiplastic biofilms and is the first to examine how primary colonization influences the microbial community re-attachment and succession as a response to extreme weather events. Finally, it is one of the few studies to examine fungal communities, despite them containing putative plastic degraders.This research was co-financed by Greece and the European Union (European Social Fund-ESF) through the Operational Program «Human Resources Development, Education and Lifelong Learning» in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432), implemented by the State Scholarships Foundation (IKY). In addition, funding by the European Union H2020 project ELECTRA (grant agreement No. 826244) is highly appreciated.http://creativecommons.org/licenses/by/4.0/Water Research246 Karkanorachaki Aikaterini Καρκανοραχακη Αικατερινη Syranidou Evdokia Συρανιδου Ευδοκια Kalogerakis Nikos Καλογερακης Νικος Elsevier Plastics Biofilm Next generation sequencing ATR-FTIR Biodegradation