RESUMEN
The coasts of the world's oceans and seas accumulate various types of floating debris, commonly known as beach wracks, including organic seaweeds, seagrass, and ubiquitous anthropogenic waste, mainly plastic. Beach wrack microbiome (MB), surviving in the form of a biofilm, ensures decomposition and remineralization of wracks, but can also serve as a vector of potential pathogens in the environment. Through the interdisciplinary approach and comprehensive sampling design that includes geological analysis of the sediment, plastic debris composition analysis (ATR-FTIR) and application of 16S rRNA gene metabarcoding of beach wrack MBs, this study aims to describe MB in relation to beach exposure, sediment type and plastic pollution. Major contributors in beach wrack MB were Proteobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Verrucomicrobia and Firmicutes and there was significant dissimilarity between sample groups with Vibrio, Cobetia and Planococcus shaping the Exposed beach sample group and Cyclobacteriaceae and Flavobacterium shaping the Sheltered beach sample group. Our results suggest plastisphere MB is mostly shaped by beach exposure, type of seagrass, sediment type and probably beach naturalness with heavy influence of seawater MB and shows no significant dissimilarity between MBs from a variety of microplastics (MP). Putative functional analysis of MB detected plastic degradation and potential human pathogen bacteria in both beach wrack and seawater MB. The research provides the next crucial step in beach wrack MP accumulation research, MB composition and functional investigation with focus on beach exposure as an important variable.
RESUMEN
Mediterranean Sea is the sixth largest area of marine litter accumulation in the world, and plastic pollution is a growing problem in its Adriatic sub-basin. The aim of the present study was to evaluate the cultivable microbiota associated with plastic litter collected by commercial fishing trawlers in the south-eastern Adriatic Sea in comparison with microbiota in seawater and sediment. Plastic litter in the sea contains an autochthonous microbiota that is different from that of the surrounding seawater and sediment. Vibrio abundance was higher on plastic litter than in surrounding seawater and sediment. All isolated Vibrio showing resistance to ampicillin and vancomycin, while resistance to other antibiotics depended on the isolated species. Overall, this study provides for the first time information on the cultivable microbiota associated with plastic litter collected by commercial fishing trawlers and provides a data base for further studies.