Some context

Plastic debris are the first source of waste in the ocean. 80% of these plastics come from land. The worldwide plastic production is approximating 400 million tonnes per year (Geyer et al.) and is predicted to increase up to 1 800 tonnes per year by 2050 (UN GRID-Arendal). With no change in waste management, plastic debris accumulation in the ocean can only be expected to increase. Solly in 2010, 12.7 million tonnes of land-based plastic have reached the ocean (Jambeck et al. 2015).

Microplastics, majorly coming from degradation of larger plastic pieces, through weather-induced degradation on the shores (Anthony L. Adrady 2011), are found all over the marine environment. Transported by hydrodynamic mechanisms (Koi et al. 2017, Van Sebille et al. 2012 and 2020), they are distributed throughout the oceans, in the surface layer, in the sediments and water column and at surface, they accumulate in the plastic gyres.

These microplastics are widespread all over the ocean, constitute long term, resistant to degradation, hydrophobic surfaces. Micro-organisms are found attached and living on these microplastic surfaces.

The microbial Plastisphere is the ecosystem formed by these organisms on the artificial substrate offered by microplastics. The potential for plastic to be used as site for microbial attachment was already evidenced in the 1970s, yet knowledge regarding interaction between plastic and micro-organisms remains poor. It is now evidenced that micro-organisms do attach and form substrate-specific communities on plastic surface (Zettler et al. 2013).

This discovery has important implications regarding the plastic issue. The colonisation of plastic fragments by attaching microbial communities (biofouling) influences the buoyancy of these microplastics, impacting their distribution in the water column and throughout the oceans (Koi et al. 2017). Understanding better the dynamics of plastic biofouling would allow a better prediction of their distribution and estimation of their abundance. Additionally, the transport of micro-organisms on long lasting surfaces could allow the spreading of invasive species and potentially pathogens throughout the world. In the current context of global pandemic, this needs to be closely looked at. Moreover, the structure and the function of these communities could also enrich our knowledge on plastic biodegradation.

Thus, fundamental knowledge on plastispheres is highly valuable to assess microplastic environmental and human impact and to develop efficient solutions to the plastic pollution issue. Yet, little is known on their dynamics, composition, structure, functions etc.