Marine Plastic Debris: A New Surface for Microbial Colonization

Abstract

Plastics become rapidly colonized by microbes when released into marine environments. This microbial communitythe Plastispherehas recently sparked a multitude of scientific inquiries and generated a breadth of knowledge, which we bring together in this review. Besides providing a better understanding of community composition and biofilm development in marine ecosystems, we critically discuss current research on plastic biodegradation and the identification of potentially pathogenic “hitchhikers” in the Plastisphere. The Plastisphere is at the interface between the plastic and its surrounding milieu, and thus drives every interaction that this synthetic material has with its environment, from ecotoxicity and new links in marine food webs to the fate of the plastics in the water column. We conclude that research so far has not shown Plastisphere communities to starkly differ from microbial communities on other inert surfaces, which is particularly true for mature biofilm assemblages. Furthermore, despite progress that has been made in this field, we recognize that it is time to take research on plastic–Plastisphere–environment interactions a step further by identifying present gaps in our knowledge and offering our perspective on key aspects to be addressed by future studies: (I) better physical characterization of marine biofilms, (II) inclusion of relevant controls, (III) study of different successional stages, (IV) use of environmentally relevant concentrations of biofouled microplastics, and (V) prioritization of gaining a mechanistic and functional understanding of Plastisphere communities.

Global Modeled Sinking Characteristics of Biofouled Microplastic

“…Biofouling is the attachment and accumulation of biological organisms on the surface of a submerged object (Long et al, 2015;Ye & Andrady, 1991). The presence of plastic provides a new substrate for microbial communities to thrive (also known as the "plastisphere"; Wright et al (2020); Zettler et al (2013)). This can have a negative impact on other species in the euphotic zone via (1) reduced light penetration, (2) impaired oxygen and carbon dioxide production and (3) a thickened barrier for gaseous exchanges at the air-sea interface.…”

Plastics and the microbiome: impacts and solutions

“…As highlighted by Wright, et al [126], many studies have characterised the plastisphere through taxonomic analyses [112,117,121,122], however, there remains a lack of knowledge surrounding the functional potential of these communities. Bryant et al [115] were among the first to explore the metabolic potential of the plastisphere microbiome using shotgun metagenomics, hypothesising that the genomes of plastic-associated taxa would be more distinct and exhibit increased metabolic activity compared to free-living bacteria in the surrounding marine water.…”

Bridging Three Gaps in Biodegradable Plastics: Misconceptions and Truths About Biodegradation

“…The free surface energy increased after weathering of PLAlignin bioplastics (Spiridon et al, 2015). In addition, continuously pumped seawater may increase the time for microorganisms to colonize surfaces (Deroiné et al, 2014;Wright et al, 2020). Laboratory systems mimic these natural mechanical stresses by agitating incubators.…”