Impact of marine microplastic associated biofilms on environmental and human health

Marmib investigates the effect of microplastics on the spread of antimicrobial-resistant bacteria in the sea with the help of a worldwide consortium from Norway, Estonia, Germany, South Africa, Vietnam and Costa Rica. In the project, the project partners have developed a steel device for deploying microplastics in the ocean across the globe, and these incubations have now been finished in Norway, Germany, Estonia, Costa Rica and are in progress in South Africa, which will finish this autumn (South African Spring). To increase the datapoints and further analyze standardized experimental setups with microplastic biofilms, an approach using lab incubation with local sea water has been done in all locations. All samples are now beeing shipped to Oslo for DNA extractions and sequencing in November 2024. We will then use the samples in the developed bioinformatic pipeline on github. Following the 2-months visit of postdoctoral scholar Dr. Franck Lejzerowicz to MarMib collaborators at the University of Costa Rica (UCR), the bioinformatic data analysis pipeline developed for the processing of these MarMib metagenomes was installed on the UCR supercomputer and run to consistently detect plasmids and antibiotic resistance genes (ARGs) from co-assemblies using multiple state-of-the-art softwares, incl. a recent method allowing for the detection of gene accumulation on plasmid backbones. This led to the surprising discovery of metal and antibiotic resistance enrichments as plasmids evolve along an anthropogenic gradient. This discovery is reported in a research article submitted to Nature Microbiology on September 25th 2024. Collaboration with NOAA's Atlantic Oceanographic and Meteorological Laboratory was initiated and resulted in master student Kristian Have Furnes joining the R/V Langseth cruise "GO-SHIP A13.5" (Cape Town - Cape Verde, Feb 1st to March 23rd 2024)) to perform a microplastic incubation experiment complementing the in vitro experiment performed at all MarMib network locations simultaneously. Furnes will complete his Msc in October 2024. In addition, 4 scientifc aritcles are under review and are expected to be published in 2024/early 2025. A breakthrough for MarMib would be to separate microplastics from complex environmental samples. Hence, we generated material for an innovative high-throughput sorting technology (COPAS, Union Biometrica) coupled to an AI developed by our collaborators Prof Camila Filgueiras (University of North Carolina Asheville) and Dr Denis Willett (North Carolina State University). Microplastic dust were sent to North Carolina in July and the first test results are imminent, after delays with the shipping of a new, demo version of the instrument, now equipped with improved lasers and camera to extract features for AI training. In parallel, a microbiome biofilm formation protocol is being developed at UiO to obtain dusts colonised by biofilms of various thickness. Indeed, further tests of the AI shall aim at separating microplastic particles that not only are different in size and polymer composition, but also are coated by more of less mature and thick biofilm.

Microplastics (MP) are already recognised as environmental pollutants of increasing concern. Ubiquitous, easily dispersed and extremely abundant, MP may be one of the defining features of the Anthropocene. Antimicrobial resistance genes (AMRGs), as well as antimicrobial products, heavy metals and resistant bacteria, have also been classified as types of pollution. Recently, evidence has been accumulating which indicates that these pollutants may be acting in tandem, worsening and driving another major problem facing the world today: antimicrobial resistance. MP provide not only a surface for biofilm formation (known as the plastisphere), they also enhance horizontal gene transfer and provide a physical vessel for spreading such resistance genes between different marine environments. Studies up to now have laid this foundation, but an investigation of the AMRGs present in plastisphere communities in different marine environments and dispersed by MPs is not done. We propose to fill this knowledge gap by studying the AMRGs, especially those present on plasmids (which are transferred between bacteria more readily), of MP collected from marine and close to marine environments from Vietnam, Norway, Baltic sea (Germany/Estonia), Costa Riva and South Africa. In the first phase of the project, we plan to collect and identifying MP, sequence microbiomes and compare levels of antibiotics/metals in the waters across different environments and levels of human interaction. This will inform the second phase of the project, in which AMRGs and bacteria present in the MP communities will be determined using metagenomic approaches. We will also characterise the plasmids from the plastisphere bacteria and how ecological functions in the marine may be changed due to biofilms being transported by the ocean to new locations. Finally, we will be to interact with policymakers and address the general public in advice on generating the next steps to address the problem of plastic waste.