Assessing marine phytoplankton eco-evolutionary dynamics and physiological responses to environmental change

Anthropogenic emissions of carbon dioxide (CO2) resulting from fossil fuel burning and changes in land use are affecting our marine environment; for example leading to ocean acidification or ocean warming. In order to understand how climate change will affect biological communities we need to understand all levels of biological responses. Community change as a response to environmental drivers are composed of three components: the physiological responses within an organism, described by its phenotypic plasticity or reaction norm and the ecological and evolutionary responses which are associated with changes on the species and genotype level, respectively. Moreover, there may be eco-evolutionary coupling, thus either ecological interactions such as competition that modify evolutionary responses to physico-chemical changes, or evolutionary change that feeds back to change ecological interactions. Here I study for the first time over the long-term (up to 220 generations) how among two competing phytoplankton species the different response types play out, and whether or not coupling of ecological and evolutionary processes can be found. Additionally I investigated the short-term inter- and intraspecific responses of three phytoplankton species to increased CO2 and what role competitive interactions play on the short-term in a two-species ´community´.