The Invisible Living World: Beyond Our Naked Eye - Amazing microalgae: tiny helpers in water

Microalgae are microscopic, photosynthetic organisms found in freshwater and marine ecosystems. They are primary producers in the aquatic food chain.

Unlike higher plants, microalgae do not have roots, stems, or leaves, but they contain chlorophyll and other pigments for photosynthesis.

Photosynthesis in microalgae: They convert light energy into chemical energy, using carbon dioxide ($CO_2$) and water ($H_2O$) to produce glucose ($C_6H_{12}O_6$) and oxygen ($O_2$).

Microalgae play a crucial role in the environment by producing over $50\%$ of the world's atmospheric oxygen.

Diatoms are a special type of microalgae with silica-based cell walls ($SiO_2$), often referred to as 'jewels of the sea' due to their intricate patterns.

Commercial Importance: Microalgae like Spirulina and Chlorella are used as single-cell proteins (SCP) and health supplements.

Environmental Role: They are used in wastewater treatment to remove nitrogen ($N$) and phosphorus ($P$) and as a source for carbon sequestration to reduce greenhouse gases.

Biofuels: Some microalgae store energy as oils (lipids), which can be extracted and converted into biodiesel.

Algal Blooms: Excessive growth of microalgae, often caused by nutrient runoff (Eutrophication), can deplete dissolved oxygen levels in water, leading to the death of aquatic life.