Marine Debris Indicators: What’s Next?

Colonization and biodegradation of wadded sticks for domestic use in marine conditions

JACQUIN Justine 1*, CALLAC Nolwenn 1,2, CHENG Jingguang 1, ODOBEL Charlène 1, Meistertzheim Anne-Leila 1,3, GIRAUD Carolane 1, PUJO-PAY Mireille 1, CONAN Pascal 1, BARBE Valérie 5, BRUZAUD Stéphane 4, DENOUAL Clément 4, GHIGLIONE Jean-François 1.

(1) CNRS, Sorbonne Universités, UMR 7621, Laboratoire d’Océanographie Microbienne, Observatoire Océanologique de Banyuls, France (2) IFREMER Unité de Recherche Lagons, Ecosystèmes et Aquaculture Durable (LEAD-NC) Nouvelle Calédonie (3) SAS Plastic@Sea et Sorbonne Universités, Laboratoire d’Océanographie Microbienne, Observatoire Océanologique de Banyuls, France (4) Institut de Recherche Dupuy de Lôme (IRDL), Université de Bretagne-Sud, UMR CNRS 6027, Rue Saint Maudé, 56321 Lorient (5) Génomique Métabolique, Genoscope, Institut de biologie François Jacob, Commissariat à l'Energie Atomique (CEA), CNRS, Université Evry, Université Paris-Saclay, Evry, France.

The BIOTIGES project has been mandated by the Ministry of Ecological Transition of France to find substitutes for sticks for household use that will be banned in 2020, identified as ubiquitous in the form of waste. The study was conducted in two phases to study their colonization (60 days) and their biodegradation (94 days) in the marine environment. Microbial colonization has been studied in open-sea aquarium (Banyuls Bay) for 60 days, according to Dussud et al. (2018, Frontiers in Microbiology, 9: 1571). The Phylum Proteobacteria was predominant (80.2% and composed of 54.6% Alphaproteobacteria, 40.5% Gammaproteobacteria and 4.7% Deltaproteobacteria.In this phase of colonization, abundance (cytometry ) and microbial activity (incorporation of radioactive leucine) evolve over time.The multivariate statistical analyzes indicate that the diversity depends more on the kinetics of colonization than on the type of polymer. Biodegradation was discussed on the same batonets transferred to a minimum medium without any other source of carbon. This transfer is accompanied by a change in the structure of the communities, with a decrease of Proteobacteria (54.8%) in favor of Bacteroidetes (30.8%) and Planctomycetes (10.6%). For substrates resistant to degradation (PLA, PP and PBS), the microbial activity drops after 15 days in minimum medium with little change in diversity over time. For "biodegradable" substrates (wood, PHA, paper, PBAT), the activities remain high with a succession of microbial communities for 94 days. This preliminary work allowed us to identify potential bacterial actors of the biodegradation of different wadded sticks. They also help orient our research into genomics and metagenomics to better understand biodegradation mechanisms (see Jacquin et al., 2019, Frontiers in Microbiology, 10: 865).

Type of contribution: Poster.

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