Associate professor, Sorbonne University

EDYCO team Leader

Pascal riera

Team Eco-geochemistry and DYnamics of COastal ecosystems

scientific interests

Isotopic ecology - marine food webs

My research activity is related to the trophic functioning of coastal ecosystems. More precisely, I use stable isotopes as first tool in order to develop the next axes:

Structure and functioning of food webs associated to benthic communities (rocky shores, mudflats, salt marshes, kelp forests) submitted to various anthropogenic impacts.

Properties of food webs: stability, plasticity, connectivity, diversity of trophic pathways

Long term monitoring using natural stable isotopes in rocky shores and soft bottom substrates

Experimentations based on stable isotopes labelling (13C, 15N) to characterized and quantify trophic fluxes from nutrients to algae to invertebrates, and the fate of molecular compounds (alginates) via the use of various isotopic technics (EA-IRMS, DNA-SIP, NanoSIMS) and metagenomics



Associate professor at Sorbonne University - Station Biologique de Roscoff since 1998

2005 : Habilitation à diriger des recherches, Sciences de la Vie et de la Santé, UPMC Isotopic ecology. Contribution of carbon and nitrogen to the study of littoral and coastal food webs.

1996-1998: Contract post-doctoral at “Marine Science Institute” (Texas) and Marie Curie - Training Mobility Research au NIOO-CEME (The Netherlands) -

1995: PhD of University of Bordeaux I. Oceanography. Origin and fate of organic matter in an estuarine ecosystem. Application of natural stable isotopes.



Biostatistics, Ecology, Zoology, stable isotopes



since 2017

  • Sturbois A, Cozic A, Schaal G, Desroy N, Riera P, Le Pape O, Le Mao P, Ponsero A Carpentier A. 2022. Stomach content and stable isotope analyses provide complementary insights into the trophic ecology of coastal temperate bentho-demersal assemblages under environmental and anthropogenic pressures. Marine Environmental Research 182: 105770. 10.1016/j.marenvres.2022.105770

  • Sturbois A., Riera P, Desroy N, Brébant T, Carpentier A, Ponsero A, Schaal G. 2022. Saptio-temporal patterns in stable isotope composition of a benthic intertidal food web reveal limited influence of salt marsh vegetation and green tide. Marine Environmental Research, 175: 105572.  doi : 10.1016/j.marenvres.2022.105572

  • Sturbois, A., Cucherousset, J., De Cáceres, M., Desroy, N., Riera, P., Carpentier, A., Quillien, N., Grall, J., Espinasse, B., Cherel, Y., Schaal, G., 2022. Stable Isotope Trajectory Analysis (SITA): A new approach to quantify and visualize dynamics in stable isotope studies. Ecological Monographs. e1501. doi : 10.1002/ecm.1501

  • Sturbois A, Cormy G, Schaal G, Gauthier O, A. Ponsero A. Le Mao P, Riera P, Desroy N. 2021. Characterizing spatio-temporal changes in benthic communities: Taxonomic and functional trajectories of intertidal assemblages in the bay of Saint-Brieuc (English Channel). Estuarine, Coastal and Shelf Science 262, 107603. doi:10.1016/j.ecss.2021.107603

  • Sturbois A., Cormy G., Le Moal A., Schaal G., Broudin C., Thiébaut E., Ponsero A., Le Mao P., Jones, A., Riera P., Gauthier O., Desroy N. 2021. Using ecological trajectories to track long-term taxonomic and functional changes in benthic shallow soft-bottom communities (Bay of Saint-Brieuc, English Channel). Aquatic Conser. Mar. Fresh. Ecosyst. doi: 10.1002/aqc.3704

  • Thomas F, Le Duff N, Wu TD, Cébron A, Uroz S, Riera P, Leroux C, Tanguy G, Legeay E, Guerquin-Kern JL. 2021. Isotopic tracing reveals single-cell assimilation of a macroalgal polysaccharide by a few marine Flavobacteria and Gammaproteobacteria. The ISME Journal. doi: 10.1038/s41396-021-00987-x

  • Charles F., Riera P., Sauriau P.G., Lantoine F., Lebreton B., Agogue H. & Hourdez S. 2020. Trophic niche partitioning in marine wood-borers revealed by stable isotope analysis. Aquat. Biol., 29: 33-43.

  • de Bettignies F., Dauby P., Lepoint G., Riera P., Bocher E., Bohner O., Broudin C., Houbin C., Leroux C., Loisel S., Davoult D. 2020.Temporal succession of macrofaunal community associated with kelp fragment accumulations in an in situ experiment. Marine Ecology Progress Series. 656: 109-121. 10.3354/meps13391

  • Legrand E., Martin S., Leroux C. & Riera P. 2020. Using stable isotope analysis to determine the effects of ocean acidification and warming on trophic interactions in a maerl bed community. Mar. Ecol.-Evol. Persp., online: 13.  10.1111/maec.12612  

  • Thomas F., Le Duff N., Leroux C., Dartevelle1 L., Riera P. 2020. Isotopic labelling of cultured macroalgae and isolation of 13C-labeled cell wall polysaccharides for trophic investigations. Advances in Botanical Research. Vol. 95: 1-17. doi:10.1016/bs.abr.2019.11.005

  • Charles F., Riera P., Sauriau P.G., Lantoine F., Lebreton B., Agogué H. & Hourdez S. 2019. Trophic niche partitioning in marine wood-borers revealed by stable isotope analysis. Aquat. Biol., 29: 33-43. 10.3354/ab00723

  • Legrand E, Riera P, Lutier M, Coudret J, Grall J, Martin S. 2019. Grazers increase the sensitivity of coralline algae to ocean acidification and warming. Journal of Sea Research 148-149: 1-7.

  • Charles F, Sauriau P-G, Aubert F., Lebreton B, Lantoine F., Riera P. 2018 Sources partitioning in the diet of the shipworm Bankia carinata (J.E. Gray, 1827): An experimental study based on stable isotopes. Marine Environmental Research 142: 208-213.  
  • Legrand E, Riera P, Pouliquen L, Bohner O, Cariou T, Martin S. 2018. Ecological characterization of intertidal rockpools: Seasonal and diurnal monitoring of physico-chemical parameters Regional Studies in Marine Science 17: 1-10.
  • Legrand E, Riera P, Bohner O, Coudret J, Schlicklin F, Derrien M, Martin S. 2018. Impact of ocean acidification and warming on the productivity of a rock pool community. Marine Environmental Research 136: 78-88
  • Legrand E, Martin S., Leroux C., Riera P. 2018. Effect of temperature on an alga-grazer trophic transfer: a dual stable isotope (13C, 15N) labeling experiment. Marine Ecology 39: 1-6. e12495.
  • Legrand E, Riera P, Lutier M, Coudret J, Grall J, Martin S 2017. Species interactions can shift the response of a maerl bed community to ocean acidification and warming. Biogeosciences 14: 5359-5376
  • Davoult D, Surget G, Stiger-Pouvreau V, Noisette F, Riera P, Stagnol D, Androuin T, Poupart N. 2017. Multiple effects of a Gracilaria vermiculophylla invasion on estuarine mudflat functioning and diversity. Marine Environmental Research. 131: 227-235.
  • Bordeyne F., Davoult D., Migné A., Bertaud Du Chazaud E., Leroux C., Riera P. 2017. Trophic structure of two intertidal Fucus spp. communities along a vertical gradient: Similarity and seasonal stability evidenced with δ13C and δ15N. Journal of Sea Research 120: 50-59.
  •  Liénart, C., Savoye, N., Bozec, Y., Breton, E., Conan, P., David, V., Feunteun, E., Grangeré, K., Kerhervé, P., Lebreton, B., Lefebvre, S., L'Helguen, S., Mousseau, L., Raimbault, P., Richard, P., Riera, P., Sauriau, P-G., Schaal, G., Aubert, F., Aubin, S., Bichon, S., Boinet, C., Bourasseau, L., Bréret, M., Caparros, J., Cariou, T., Charlier, K., Claquin, P., Cornille, V., Corre, A-M., Costes, L., Crispi, O., Crouvoisier, M., Czamanski, M., Del Amo, Y., Derriennic, H., Dindinaud, F., Durozier, M., Hanquiez, V., Nowaczyk, A., Devesa, J., Ferreira, S., Fornier, M., Garcia, F., Garcia, N., Geslin, S., Grossteffan, E., Gueux, A., Guillaudeau, J., Guillou, G., Joly, O., Lachaussée, N., Lafont, M., Lamoureux, J., Lecuyer, E., Lehodey, J-P., Lemeille, D., Leroux, C., Macé, E., Maria, E., Pineau, P., Petit, F., Pujo-Pay, M., Rimelin-Maury, P., Sultan, E. 2017. Dynamics of particulate organic matter composition in coastal systems: a spatio-temporal study at multi-systems scale. Progress in Oceanography. 156: 221-239.