Classification of algae, Ecological role of algae

Classification of algae (here we will discus about its 11divisions), Ecological role of algae (Source of food, source of fodder ,source of oxygen, Pisciculture, Habitat Formation, Symbiosis, Harmful Algal Blooms (HABs) Eutrophication Impact, Pollution Indicator, Climate Change Indicator, Source of Fertilizer)