Identification and Characterization of Dissolved Black Carbon and Its Interactions with Zooplankton

Air pollution particles generated by the incomplete burning of fossil fuels can be dispersed in the atmosphere or fall in the soil, being transported to aquatic environments by deposition or river currents. [1] The dissolved fraction of BC is composed of a set of heterogeneous pyrogenic compounds. Dissolved Black Carbon (DBC), a soluble part of BC (0.2 μm – 0.7 μm), consists exclusively of polycondensed aromatic molecules. [2] In the marine environment, zooplankton can modify the physicochemical characteristics of pollutants in the water column (e.g., by absorption, transformation, and elimination), playing an important role in the biomagnification of pollutants in food webs. The knowledge about the interactions between zooplankton and anthropogenic pollutants is still scarce. [3,4] In this study, we used two-photon confocal microscopy and our recent advances in the optical characterization of Particulate (PBC) and Dissolved Black Carbon to identify them in copepods collected in the Bay of Toulon, France, in vivo. We incubated the copepods after the sea sampling with a typical PBC concentration of coast regions and high anthropogenic activity. The images obtained revealed the localization of the particles in the digestive tract of the animals, confirming their ingestion by these marine species after 48h of incubation. The identification was made by the previous PBC and DBC fluorescence emission characterization. Inside of the copepods the signal ressembly of the DBC particles who are knowing to be toxic and highly dangerous. Next steps include the investigation of DBC toxicity effects in copepods and their chemical transformation.

 

1- Wagner, S., Jaffé, R., & Stubbins, A. (2018). Dissolved black carbon in aquatic ecosystems. Limnology And Oceanography Letters, 3(3), 168–185. -https://doi.org/10.1002/LOL2.10076

2- MARTINOT, P. L. et al. Assessing the bioavailability of black carbon-derived dissolved organic matter for marine heterotrophic prokaryotes. Science of the Total Environment, v. 901, p. 165802, 2023. DOI: 10.1016/j.scitotenv.2023.165802.

3- ZIYAADINI, M. et al. Assessment of concentration, bioaccumulation and sources of polycyclic aromatic hydrocarbons in zooplankton of Chabahar Bay. Marine Pollution Bulletin, v. 107, n. 1, p. 408–412, 2016. DOI: 10.1016/j.marpolbul.2016.02.045.

4- THIRUNAVUKKARASU, S.; HWANG, J. S. Genotoxic effects of marine pollutants on coastal meso-zooplankton populations – a mini-review. Marine Pollution Bulletin, v. 205, 2024. DOI: 10.1016/j.marpolbul.2024.116548.