Why in the News?

A recent study finds microalgae are firing up a light-responsive protein to use sunlight for growth.

What is the Microalgae?

• Microalgae are microscopic algae prevalent in freshwater and marine environments, consisting of unicellular species that can exist independently or in chains and groups.
• Comprising unicellular algal varieties such as green algae, diatoms, and dinoflagellates, these organisms exhibit sizes ranging from a few micrometres to several hundred micrometres.
• Their colour, determined by predominant pigments, categorizes them into groups like green, red, or brown.
• Unlike higher plants, microalgae lack roots, stems, or leaves, and they predominantly engage in photosynthesis, fueled by photosynthetic pigments.
• Heterotrophic microalgae, lacking these pigments, rely on other organisms for sustenance.

Significance:

• Microalgae play a foundational role in the aquatic food chain, offering vital nutrients for zooplankton, small fish, and various aquatic organisms.
• They serve as a primary food source for filter-feeding organisms.
• Moreover, photosynthetic microalgae contribute significantly to global carbon and oxygen cycles, absorbing carbon dioxide and generating oxygen through photosynthesis.
• Approximately half of atmospheric oxygen is produced by these organisms.
• Microalgae can also establish symbiotic relationships, as seen in their association with corals (zooxanthellae), providing nutrients through photosynthesis.
• Certain microalgae, like Nostoc, Anabaena, and Oscillatoria, exhibit nitrogen-fixing capabilities.
• Additionally, microalgae are rich in nutrients and can be consumed by humans. Notable examples like Spirulina and Chlorella are often utilized as dietary supplements.

What are Macroalgae?

• Macroalgae, commonly known as seaweeds, are marine plants engaging in photosynthesis but reproducing without flowers.
• Visible to the naked eye, in contrast to microalgae, they typically grow attached to the seabed or reef substrate.
• These macroscopic algae play crucial roles in reef ecosystems, providing both food and habitat for a diverse array of species while contributing significantly to nutrient dynamics.