2. Algae are primary producers mainly in the aquatic ecosystems. Despite their numerous advantages they still do have different harmful effects, of which algal bloom is the main one caused by different species. Among those bloom-causing species, Ostreopsis is responsible for respiratory and cutaneous irritation in humans and mass mortality of marine organisms. Discuss the ecology of Ostreopsis (3pt).
3. Discuss the role of cyanobacteria (blue-green algae) for the very existence of life on the planet earth (3pt).