Major Role of Surrounding Environment in Shaping Biofilm Community Composition on Marine Plastic Debris

Marco Basili,Gian Marco Luna,Donato Giovannelli,Rocco De Marco,Carla Vignaroli,Elena Manini,Grazia Marina Quero,Carlo Giacomo Avio

doi:10.3389/fmars.2020.00262

Abstract

Plastic debris in aquatic environments is colonized by microbes, yet factors influencing biofilm development and composition on plastics remain poorly understood. Here, we explored the microbial assemblages associated with different types of plastic debris collected from two coastal sites in the Mediterranean Sea. All plastic samples were heavily colonized by prokaryotes, with abundances up to 1.9×107 cells/cm2. Microbial assemblages on plastics significantly differed between the two geographic areas but not between polymer types, suggesting a major role of the environment as source for the plastisphere composition. Nevertheless, plastic communities differed from those in the surrounding seawater and sediments, indicating a further selection of microbial taxa on the plastic substrates. The presence of potential pathogens on the plastic surface reflected the levels of microbial pollution in the surrounding environment, regardless of the polymer type, and confirmed the role of plastics as carriers for potentially pathogenic microorganisms across the coastal ocean, deserving further investigations.

Highlights

Synthetic thermoplastic polymers, commonly known as plastics, are widespread in our society and constitute one of the most used materials in our everyday life (Barnes et al, 2009)
We selected two sites located on the opposite coasts of Italy, Naples (Tyrrhenian Sea) and Ancona (Adriatic Sea), on the basis of their geographical distance and different levels of human impact, and we described the morphology, abundance and diversity of the prokaryotic communities living on plastic debris
Plastic samples were identified as PE, PP, and polystyrene (PS) through μFT-IR analysis

Summary

Introduction

Commonly known as plastics, are widespread in our society and constitute one of the most used materials in our everyday life (Barnes et al, 2009). Increasing concerns have focused on plastics as a cause of injuries and other health problems for marine organisms (Brouwer et al, 2017) and on their role as a vector of persistent organic pollutants (POPs; Andrady, 2011), invasive species (Barnes and Fraser, 2003; Gregory, 2009), as well as pathogenic species (Keswani et al, 2016) Whatever their size, in the aquatic environment, plastics represent a physical substrate for microbial colonization and biofilm formation. Due to their known ability to adapt quickly to new environmental conditions (Wiedenbeck and Cohan, 2011), it has been hypothesized that some marine microorganisms are able to use the plastic debris as a new substrate for the formation of biofilm and to further use plastic polymers as a carbon source (Balasubramanian et al, 2010; Bryant et al, 2016)

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Conclusion