Abstract: Algae always plays a key role in stabilizing the balance and the biodiversity of aquatic ecosystem. However, during the growth of algae, the normal life activities are always susceptible to various environmental factors. In this paper, we analyzed the effects of three types of environmental stress factors including meteorological factors (UV-B, drought, high temperature, and etc.), pollutants (heavy metals, nanomaterials, organic pollutants, rare earth elements, and etc.), and water body coexisting matter (water particles, excessive nutrients, H₂O₂, and etc.) on the life activities of different algae species (Cyanophyta, Chlorophyta, Bacillariophyta and Phaeophyta). The effects of different environmental stress factors on the biological characteristics of algae were systematically reviewed from the changes of antioxidant enzyme activities, cell ultrastructural changes and DNA damage in algae. Results demonstrated that during the growth of algal cells, a set of ROS scavenging antioxidant defense system was formed, which reduced the body damage of algal when attacked by reactive oxygen species; nevertheless, when the production speed of reactive oxygen species exceeded the scavenging ability of antioxidant defense system, excessive reactive oxygen species would cause oxidative stress to the algal body, resulting in the loss of protein function, ultrastructural damage, DNA damage and mutation, and in particular when serious, would cause cell metabolism disorder, and ultimately inhibit the growth and development of algae. The results offer a basis for further study on the growth of algae and the changes of its molecular biological characteristics under stress.

Key words: algae, environmental stress factors, antioxidant enzyme activity, DNA damage, cell's ultrastructure