Live to tell: Have phytoplankton evolved in response to environmental pollution during the last centuries?
In perturbed environments some species will go extinct while others persist (are resilient). The Baltic Sea is an ecosystem that is suffering from multiple stressors. In this system planktonic diatoms play a pivotal role as primary producers at the base of the food chain. Changes due to loss of diatom species may therefore cascade throughout the trophic web.
We will study the underlying mechanisms of resilience (genetic adaptation or phenotypic plasticity) by using two diatom species from a cupper contaminated inlet. One species is a permanent resident of the area, whereas the other disappeared when [Cu2+] increased, but recolonized when water quality later improved.
We will sample undisturbed sediment cores, date them by isotopes, and revive populations from before, during, and after the perturbation. In ecotoxicological pollution induced tolerance tests we will quantify and compare the resilient and non-resilient species’ tolerance to cupper. Different populations isolated from diverse natural pollution regimes will be tested to infer the importance of plasticity or genetic adaptation by tolerance selection experiments.