Micro‐by‐micro interactions: How microorganisms influence the fate of marine microplastics

Abstract

Due to their small particle size and wide distribution, microplastics can be incorporated into the biogeochemical pathways and food webs of the marine water column and sediment. Our understanding of microplastics in these pathways is still nascent, but of fundamental importance to estimate plastic's environmental fate and potential remediation. A massive research effort across fields in the last years has brought our understanding further, but there is a strong need to streamline and converge findings. Here, we discuss evidence from controlled laboratory experiments and field studies on microbe-plastic interactions and consider the biogeochemical relevance. Particular focus is on new methods and analytical approaches to understand the two-way interactions between microorganisms and microplastics and the implications for the environmental fate of marine plastic litter. AbstractMicroorganisms drive the biogeochemical cycles that link abiotic and biotic processes in the aqueous environment and are intricately associated with plastic debris. The presence of microplastics in water and sediment introduces new concerns as small particle size allows for increased pathways of microplastics in the food web and element cycles. In this review, we present the current state of knowledge on microbe-plastic interactions and summarize the potential impact of biogeochemical processes on plastic distribution, cycling, transport, and sedimentation. We explore how microbe-plastic interactions influence the exposure of consumers to microplastics and plastic degradation products. Key methods used to elucidate biofilm development, microbial biodegradation, and microplastic detection in the aqueous environment are discussed. Finally, we comment on potential future questions and research directions needed to further define the role of microorganisms in the environmental fate of microplastics.

The global biological microplastic particle sink

“…In the current model version there are no abiotic breakdown rates (i.e., photo-degradation 39 ) or respiration losses 47 removing MP from circulation.…”

Food or just a free ride? A meta-analysis reveals the global diversity of the Plastisphere

“…Microbial members of the Plastisphere have been found to be: (i) different from communities that colonize other surfaces [25][26][27]; (ii) not different from communities that colonize other surfaces [28]; (iii) only different from communities colonizing other surfaces under specific environmental conditions [29,30] or at specific time points [31]; (iv) more diverse than other microbial communities [32]; (v) less diverse than other microbial communities [33,34]; (vi) potentially degrading the plastics that they colonize [35,36]; (vii) capable of degrading plastic additives [33,37,38]; and (viii) pathogenic and/or carrying antimicrobial resistance genes [39][40][41][42]. The marine Plastisphere has been heavily reviewed within the last year, e.g., [18,[43][44][45][46], and there are also several recent reviews on plastic biodegradation, e.g., [47][48][49]. However, definitive answers on the metabolic capabilities of the Plastisphere or the factors that drive its formation and composition are unknown.…”

Deep-sea plastisphere: long-term colonization by plastic-associated bacterial and archaeal communities in the Southwest Atlantic Ocean

“…When comparing our microbial taxa from plastic substrates with previous studies related to the plastisphere in epipelagic ecosystems we found several families in common, such as Microtrichaceae, Rhizobiaceae, Halieaceae, Spongiibacteraceae, Rhodobacteraceae, Micavibrionaceae, Flavobacteriaceae, Halomonadaceae, Kangiellaceae, Hyphomonadaceae, Comamonadaceae, Oleiphilaceae and Bacillaceae (Amaral-Zettler et al, 2020; Feng et al, 2020; Pinto et al, 2019; Rogers et al, 2020). The family Oleiphilaceae comprises members that obligately utilize hydrocarbons through the alkane hydroxylase ( AlkB ) pathway (Golyshin et al, 2002); its detection in our plastic samples likely indicates their potential role in degrading plastic substrates in deep-sea ecosystems.…”