The primary role of algae in aquatic ecosystems is as a primary source of photosynthesis. Algae convert sunlight into energy, producing oxygen and organic compounds that support various aquatic life forms, including fish and invertebrates. They form the base of the aquatic food web, serving as a crucial food source for herbivores. Algae also contribute to water quality by absorbing nutrients and filtering pollutants. Their presence and health signify the overall functioning of aquatic ecosystems, making algae vital for sustaining biodiversity and maintaining ecosystem services.