LASA – Laboratoire des sciences aquatiques
Département des sciences fondamentales
Université du Québec à Chicoutimi
555, boulevard de l’Université
Chicoutimi (Québec) G7H 2B1
Canada
Email: grosbois.gui@gmail.com
Tel: 1-418- 545-5011 ext 2336

Research while making my Ph.D. in LASA (Français)

Aquatic ecosystems are influenced by terrestrial ecosystems via terrestrial inputs (allochthonous). As a PhD student, my research aimed to assess the impact of terrestrial organic matter on aquatic organisms. In boreal lakes, these terrestrial inputs are considered as bad quality food source for the growth and health of zooplankton and fish as they contain few essential fatty acids (omega-3, omega-6). However, I demonstrated in my PhD thesis, that this inputs were widely assimilated and used by zooplankton during high growth periods. This assimilation was spatially heterogeneous within a lake and locally influenced by macrophytes. On the contrary, during low growth periods e.g. in winter, zooplankton rather accumulated essential fatty acids from algae under the ice but no terrestrial fatty acids. During this project, I used food web tools as stable isotopes (¹³C, ¹⁵N, ²H) or fatty acid analyses that allow to trace food sources and to assess their impact on zooplankton growth. It is predicted that terrestrial inputs will increase with climate change and decrease algal production via a limitation of the access to sunlight. This research aims thus to help predicting the future health and growth evolution of zooplankton and fish in aquatic ecosystems.

Publications last updated 2017

Grosbois, G., Mariash, H., Schneider, T., and Rautio, M. (2017) Under-ice availability of phytoplankton lipids is key to freshwater zooplankton winter survival. Scientific Reports 7:11543, DOI: 10.1038/s41598-017-10956-0.

Grosbois, G., del Giorgio, P. A. & Rautio, M. (2017) Zooplankton allochthony is spatially heterogeneous in a boreal lake. Freshwater Biology, 62, 474-490, DOI: 10.1111/fwb.12879.

Schneider, T., Grosbois, G., Vincent, W. F. & Rautio, M. (2017) Saving for the future: Pre-winter uptake of algal lipids supports copepod egg production in spring. Freshwater Biology. 62, 1063-1072, DOI:10.1111/fwb.12925.

Schneider, T., Grosbois G., Vincent W.F. & Rautio M. (2016) Carotenoid accumulation in copepods is related to lipid metabolism and reproduction rather than to UV-protection. Limnology and Oceanography, 61, 1201-1213, DOI: 10.1002/lno.10283.

Piscart, C., Roussel, J. M., Dick, J. T. A., Grosbois, G. & P. Marmonier. (2011) Effects of coexistence on habitat use and trophic ecology of interacting native and invasive amphipods. Freshwater Biology 56:325-334, DOI: 10.1111/j.1365-2427.2010.02500.x.

Manuscripts

Grosbois, G. & Rautio, M. Active and colorful life under the lake ice. (accepted for publication in Ecology – Scientific Naturalist 2017).

Grosbois, G., Vachon, D., del Giorgio, P. and Rautio, M. Terrestrial carbon supports zooplankton production in summer but not in winter in a boreal lake. Manuscript to be submitted.

Reports

Grosbois, G. 2009. Distribution and habitat characterization of two Mediterranean Gastropods in occidental Provence. Ms.S. thesis. 30p. (In French).

Grosbois, G. 2008. Horizontal and vertical distribution of invertebrate communities from the hyporheic zone of a Mediterranean river. Master 1 degree thesis. 18p. (In French).

Grosbois, G. 2007. Spatial and trophic competition between invasive and endemic Amphipods in Brittany. Master 1 degree thesis. 23p. (In French).

Conferences last updated 2017

Grosbois, G., Vachon, D., del Giorgio, P. & Rautio, M. (2016) Zooplankton production and allochthony follow different seasonal patterns in a boreal lake. SIL XXXIII Congress. Torino, Italy. Aug 2016. Oral presentation.

Rautio, M. Grosbois, G., Mariash, H., Schneider, T. (2016) The underestimated role of autumn for zooplankton seasonal resource use and reproduction, as indicated by stable isotope, fatty acid and pigment analyses. SIL XXXIII Congress. Torino, Italy. Aug 2016. Oral presentation.

Grosbois, G., del Giorgio, P. & Rautio, M. (2014) River and macrophyte effect on aquatic food sources and their integration in zooplankton in a boreal lake. Joint Aquatic Science Meeting. Portland, USA. May 2014. Oral presentation.

Grosbois, G., del Giorgio, P. & Rautio, M. 2014. River and Macrophyte influence on food source integration in zooplankton in a boreal lake. 24th GRIL symposium, Saint Hippolyte, Québec, Canada, Feb. 2014. Awarded as best PhD student poster.

Grosbois, G. & Rautio, M. 2013. Seasonal pattern of seston and zooplankton isotope signatures. 23rd GRIL symposium, Saint Hippolyte, Québec, Canada, Mar. 2013. Oral presentation.

Grosbois, G., Sastri, A. & Rautio, M. 2012. Zooplankton productivity dependency on terrestrial subsidies in boreal lake. ASLO Aquatic Sciences meeting. Otsu, Japan. July 2012. Poster.

Grosbois, G., del Giorgio, P. & Rautio, M. 2012. Seasonal pattern of the integration of allochthonous carbon in boreal aquatic food web. 22nd GRIL symposium, Saint Ferdinand, Québec, Canada. Mar. 2012. Poster.

Piscart, C., Grosbois, G., Rousselet, J-M & Marmonier, P. (2007) Biogéographie et micro-répartition des amphipodes de Bretagne : conséquence sur les réseaux trophiques associés à l’espèce endémique Gammarus duebeni celticus 50th AFL congress (French association of limnology), Toulouse Nov. 2007. Poster.