Global climate change affects productivity and species composition of freshwater and marine aquatic ecosystems by raising temperatures, ocean acidification, excessive solar UV and visible radiation. Effects on bacterioplankton and viruses, phytoplankton and macroalgae have farreaching consequences for primary consumers such as zooplankton, invertebrates and vertebrates, as well as on human consumption of fish, crustaceans and mollusks. It has affected the habitation of the Arctic and Antarctic oceans the most so far. Increasing pollution from terrestrial runoff, industrial, municipal and household wastes as well as marine transportation and plastic debris also affect aquatic ecosystems.