Assessing the bioavailability of black carbon-derived dissolved organic matter for marine heterotrophic prokaryotes

Pauline L Martinot; Catherine Guigue; Sandrine Chifflet; Philippe Cuny; Aude Barani; Morgane Didry; Clara Dignan; Léa Guyomarc'h; Nathalie Pradel; Olivier Pringault; France Van Wambeke; Cam Tu Vu; Xavier Mari; Marc Tedetti

doi:10.1016/j.scitotenv.2023.165802

Assessing the bioavailability of black carbon-derived dissolved organic matter for marine heterotrophic prokaryotes

Sci Total Environ. 2023 Nov 25:901:165802. doi: 10.1016/j.scitotenv.2023.165802. Epub 2023 Jul 29.

Affiliations

¹ Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France; Water - Environment - Oceanography (WEO) Department, University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), Hanoi, Viet Nam. Electronic address: pauline.martinot@mio.osupytheas.fr.
² Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France; Water - Environment - Oceanography (WEO) Department, University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), Hanoi, Viet Nam.
³ Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France.
⁴ Université de Toulon, Aix Marseille Université, CNRS, IRD, MIO, Toulon, France.
⁵ Water - Environment - Oceanography (WEO) Department, University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), Hanoi, Viet Nam.

PMID: 37524184
DOI: 10.1016/j.scitotenv.2023.165802

Abstract

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 (D_REF), oxidized diesel (D_REF-OX), and natural samples of ship soot (D_SHIP). 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 D_REF-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 D_REF and D_SHIP treatments, prokaryotic activity was oriented towards anabolism. D_REF treatment led to the highest decrease in DBC concentration (38 %). D_SHIP 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.

Keywords: Bacterial degradation; Bioavailability; Black carbon; Dissolved organic matter; Marine prokaryotes; Soot.

MeSH terms

Biological Availability
Carbon
Dissolved Organic Matter*
Polycyclic Aromatic Hydrocarbons* / analysis
Soot

Substances

Dissolved Organic Matter
Soot
Polycyclic Aromatic Hydrocarbons
Carbon