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. After the project had delays in previous years due to COVID and increased costs due to increased steel prices, in 2023 we have deployed our sampling units around the world. Incubations have now been carried out in Germany and Costa Rica, while storms have delayed deployment in South Africa. The units in Oslo and in Estonia have unfortunately been taken by storm (September-October 2023), while the unit in Vietnam has been subject to theft. Because 3 units have not been deployed as planned, we have made a mitigation plan which means that we will still be able to collect samples from these areas. We will send out plastic pieces of known polymers on steel wires that will be able to be deployed in the sea at the original locations. Together with laboratory incubation with seawater from the locations and the remaining 3 units, we will collect enough samples to carry out the planned analyses. We have now completed the first incubation in Germany and in Costa Rica, where we have completed the extraction of DNA from the polymers for sequencing. There has been a huge amount of activity among the partners in the project, with many new activities initiated. As planned, an exchange from Costa Rica to Germany is currently being carried out by a PhD student. A Post Doc funded by MarMib has completed a 2-month exchange from Oslo to Costa Rica with additional funding from the Kristine Bonnevie scholarship. Through this collaboration, we have sequenced and analyzed 27 metagenomes and 12 plasmids assembled for publication (manuscript under development). In total, 6 PHD students and 3 MSC students have the last year been involved in research related to MarMib. By the end of 2023, we will have submitted 4 articles related to MarMib, these will be reported next year. Synergy effects of the project have been great. Our team was invited by NOAA (National Oceanic and Atmospheric Administration) to join the upcoming GO-SHIP A13.5 expedition from Cape Verde to Cape Town (1 February – 23 March) to collect microplastics along a north -southern latitudinal gradient through the equator and the Southern Ocean's polar front, which is well in line with the project goal of collecting microplastics across biogeographic boundaries. Fieldwork will be carried out by Kristian Have Furnes, Norwegian national and master's student at the University of Oslo, supervised by MarMib postdoc Franck Lejzerowicz and Prof. Alexander Eiler. The expedition will end in Cape Town. There, MarMib collaborator Prof. Carlos Bezuidenhout will be able to ensure the proper handling and shipment of all marine microplastic reserve samples from the cruise, thereby expanding sampling in Cape Town. Individual, environmental microplastic samples will be sorted either manually during the cruise, in the laboratory, or based on high-throughput image processing and machine learning-based sorting technology developed by the new collaboration partner Prof. Camila Filgueiras (University of North Carolina) and Dr. Denis Willett (North Carolina State University). Four grant applications have been developed to use this technique, which has never yet been used on microplastics.

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.