Martinot P. L. auteur aut IRD Guigue Catherine auteur aut IRD Chifflet Sandrine auteur aut IRD Cuny P. auteur aut IRD Barani A. auteur aut IRD Didry M. auteur aut IRD Dignan C. auteur aut IRD Guyomarc'h L. auteur aut IRD Pradel Nathalie auteur aut IRD Pringault Olivier auteur aut IRD Van Wambeke F. auteur aut IRD Vu C. T. auteur aut IRD Mari Xavier auteur aut IRD Tedetti Marc auteur aut IRD text journalArticle eng text/pdf born digital access Here we investigated the bioavailability of black carbon (BC)-derived dissolved organic matter (DOM) for a natural mixed community of marine heterotrophic prokaryotes. We ran an in vitro biodegradation experiment that took place over 3 months and exposed a community of organisms collected in the northwestern Mediterranean Sea (Bay of Marseille, France) to three different soluble fractions of BC prepared in the laboratory from various fossil fuel combustion particulates: standard diesel (DREF), oxidized diesel (DREF-OX), and natural samples of ship soot (DSHIP). Over the course of the three months, we observed significant decreases in the concentrations of dissolved organic carbon (DOC; from 9 to 21 %), dissolved BC (DBC; from 22 to 38 %) and dissolved polycyclic aromatic hydrocarbons (d-PAH; from 24 to 64 %) along with variability in the growth dynamics and activity of the heterotrophic prokaryotic community. The heterotrophic prokaryotic community exposed to DREF-OX treatment showed the highest values of respiration and production and the highest cell abundance, associated with the highest decrease in DOC (21 %) and d-PAH (64 %) concentrations. In the DREF and DSHIP treatments, prokaryotic activity was oriented towards anabolism. DREF treatment led to the highest decrease in DBC concentration (38 %). DSHIP treatment, which presented a substantially different d-PAH and dissolved metals content to the other two treatments, showed the lowest decreases in DOC, DBC and d-PAH concentrations, as well as the lowest prokaryotic activity and biomasses. Our results indicate that BC-derived DOM, including the most condensed fraction of this material, is partly bioavailable and therefore likely to be assimilated by marine prokaryotes. The origin of BC/soot deposited at the ocean surface turns out to be a key parameter that dictates the efficiency of biodegradation of its dissolved fraction by heterotrophic prokaryotes. specialized Black carbon Soot Dissolved organic matter Marine prokaryotes Bioavailability Bacterial degradation MEDITERRANEE FRANCE 021 034 084 901 165802 [18 ] [+ Corrigendum, vol. 904, 166251] 2023 0048-9697 https://www.documentation.ird.fr/hor/fdi:010090136 10.1016/j.scitotenv.2023.165802 0048-9697 [F B010090136] https://www.documentation.ird.fr/hor/fdi:010090136 https://www.documentation.ird.fr/intranet/publi/2023-10/010090136.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2023-10-06 2025-02-24 fdi:010090136 fre