Warming and UV-B effects on phytoplankton communities in polar seas

点击翻译按钮获取中文摘要

This research deals with the influence of climate warming and enhanced UV-B radiation, two major environmental stressors, on communities of marine phytoplankton (microscopic algae). We will examine the influence of increasing temperature in the Arctic, associated with reduced ice cover, on the cell viability of phytoplankton that may be harmed by the rapid increase in light in their environment. We will also test the combined influence of warming and enhanced UV-B on phytoplankton from Antarctica and in subarctic Quebec, by using controlled experiments in outdoors mesocosms (2 m3 containers filled with local seawater). A number of these mesocosms will be exposed to increased temperature with or without enhanced UV-B simulating local ozone depletion. Since increased temperature should favor enzyme-based repair mechanisms, we hypothesize that warmer temperatures will help local phytoplakton communities (or more resistant algal groups) support the increases in irradiances (including UV radiation) associated with warming in polar environments. We will also examine the outcome of these treatments in terms of changes in phytoplankton community composition and bio-diversity to assess how warming and UV-B are transforming the communities at the base of trophic food webs in marine polar environments. This information will also be useful for satellite ocean colour applications, which are being developed for identification of several phytoplankton groups.