OligoNem – In situ methods using oligochaetes and nematodes for assessing sediment quality

Sediments play a critical role in biogeochemical cycling, and benthic processes support the base of aquatic food chains. However, sediments are often polluted and, as chemical sinks, can represent a risk for benthic communities. Even if no signs of pollution are apparent in the water column sediments can disturb the functioning of the ecosystem.It is therefore crucial to assess the sediment quality to assess the risk for aquatic ecosystems. Integrated methods for the evaluation of sediment quality do not only use physico-chemical and ecotoxicological analyses but also in situ indices that evaluate the diversity and sensitivity of macrobenthic communities. Nematodes and oligochaetes have been found to be most useful in this respect.

Significant work has already been done on the use of oligochaetes to assess the biological quality of sediments. We tested and developed indices for fine/sandy sediments of streams and lakes (IOBS and IOBL oligochaete indices) but also for the surface coarse sediments and the hyporheic zone (Functional trait FTR oligochaete index). Effect thresholds of metals in fine/sandy sediments on oligochaete communities could be established (Vivien et al., 2020) and the TRF index was found to be adequate for detecting the effects of WWTP discharges on the receiving stream (Vivien et al., 2019). In addition, oligochaete methods based on the identification of specimens using molecular biology have been tested and developed (Vivien et al., 2016; 2017; 2019; 2020; 2023).

We applied the oligochaete and nematode indices simultaneously to assess the quality of stream sediments (Beauvais et al. 2020a; 2020b), and of lake sediments (Vivien et al., in preparation). Differences in biological quality between the two indices, which could be explained by different methods for classifying taxa as sensitive and resistant to pollution, were observed. It is planned to apply oligochaete and nematode indices more widely in lakes in order to determine whether they could, in this environment, indicate in addition to the degree of eutrophication (level of oxygenation of sediments), the effects of toxic type pollutants (in particular metals, PCBs and PAH).

Publications

Pesce, S., Ferrari, B.J.D. et al. (2019) Recommandations d’un collectif franco-suisse d’experts pour une meilleure évaluation de la qualité écotoxicologique des sédiments par l’étude des communautés benthiques. Sciences Eaux & Territoires 55, 1-9
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Lefrançois, E., Apothéloz-Perret-Gentil, L., Blancher, P., Botreau, S., Chardon, C., Crepin, L., Cordier, T., Cordonier, A., Domaizon, I., Ferrari, B.J.D., Guéguen, J., Hustache, J.-C., Jacas, L., Jacquet, S., Lacroix, S., Mazenq, A.-L., Pawlowska, A., Perney, P., Pawlowski, J., Rimet, F., Rubin, J.-F., Trevisan, D., Vivien, R., Bouchez, A. (2018) Development and implementation of eco-genomic tools for aquatic ecosystem biomonitoring: the SYNAQUA French-Swiss program. Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-2172-2
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Vivien, R., Werner, I., Ferrari, B.J.D. (2018) Simultaneous preservation of the DNA quality, the community composition and the density of freshwater oligochaetes for the development of genetically based biological indices. PeerJ, DOI 10.7717/peerj.6050
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Vivien, R., Holzmann, M., Werner, I., Pawlowski, J., Lafont, M. and Ferrari, B.J.D. (2017) Cytochrome c oxidase barcodes for aquatic oligochaete identification: development of a Swiss reference database. PeerJ, DOI 10.7717/peerj.4122
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Vivien, R., Ferrari, B.J.D., Pawlowski, J. (2016) DNA barcoding of formalin‑fixed aquatic oligochaetes for biomonitoring. BMC Res Notes 9:342 DOI 10.1186/s13104-016-2140-1
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Vivien, R., Lejzerowicz, F., Pawlowski, J. (2016) Next-Generation Sequencing of Aquatic Oligochaetes: Comparison of Experimental Communities. PLoS ONE 11(2): e0148644
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Vivien, R., Lafont, M. (2015) Note faunistique sur les oligochètes aquatiques de la région genevoise et de Suisse. Revue suisse de Zoologie, 122:207-212
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