Yesterday, Coralie Delarue defended her Masters thesis in Aquatic Biology, titled "Plasticity of trait divergence in threespine stickleback (Gasterosteus aculeatus) from Lake Mývatn, Iceland". Her supervisors were Dr Bjarni K. Kristjánsson (HUC‘s Department of Aquaculture and Fish Biology) and Dr Katja Räsänen (ETH/Eawag, Switzerland). The external examiner was Dr Sigurður Snorrason (Univeristy of Iceland‘s Faculty of Life and Environmental Sciences) and moderator at the defence was Dr Stefán Óli Steingrímsson ((HUC‘s Department of Aquaculture and Fish Biology).The defence, which was well attended, took place in the department‘s conference room in Verið in Sauðárkrókur.
Lake Mývatn is one of the best-studied ecosystems in Iceland showing strong environmental gradients (e.g. in temperature, depth, substrate) and spatial and temporal differences in invertebrate composition. Many invertebrates groups are found in the lake, in particular chironomid midges and benthic cladocerans that are important prey for threespine stickleback (Gasterosteus aculeatus). As adaptive divergence in response to natural selection is frequently related to diet and/or habitat use, the spatial and temporal variation in prey type and abundance in lake Mývatn may facilitate resource-mediated diversification of stickleback. In her research, Coralie endeavoured to work out whether phenotypic differences in Mývatn‘s sticklebacks, in regard to feeding morphology and body size, are due to genetic or plastic responses. Her results strongly indicate a mixture of genetic divergence and phenotypic plasticity acting in diversification of Mývatn stickleback populations.
Coralie, who is originally from Normandy, has been at Hólar/Verið since 2014 and we will be fortunate enough to have her working here for another few months, before she leaves for new adventures in some other part of the world.
Photo Skúli Skúlason.