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Algal Blooms • Marine Ecology • Coastal Pollution • INCOIS Study • Harmful Algae Hotspots

India’s Rising Algal Blooms: A Coastal Crisis Unfolding

India’s extensive coastline is now under increasing pressure from frequent and intensifying algal blooms, according to a recent study led by T.M. Balakrishnan Nair from the Indian National Centre for Ocean Information Services (INCOIS). With nine critical hotspots identified, the research calls for urgent attention to marine health, ecosystem resilience, and livelihood protection.

🌱 What Are Algal Blooms?

Algal blooms are rapid population explosions of algae in marine or freshwater systems, often visibly discolouring the water.

• Triggered by: Excessive nitrogen and phosphorus inputs.
• Sources include: Agricultural runoff, sewage discharge, and natural nutrient upwelling.
• Algae types: Ranging from unicellular phytoplankton to multicellular varieties, altering water colour from green to red.

⚠️ Types of Algal Blooms: Helpful vs. Harmful

• Beneficial Blooms feed marine food chains, boosting fisheries.
• Harmful Algal Blooms (HABs):
  • Release toxins
  • Suffocate marine life by lowering oxygen
  • Contaminate shellfish → human health risks (e.g., paralysis, gastrointestinal illness)
  • Notorious example: Red Tides caused by dinoflagellates

📍 Hotspots Identified Along Indian Coasts

Western Coast:

• Goa
• Mangaluru
• Kozhikode
• Kochi
• Vizhinjam Bay

Eastern Coast:

• Gopalpur
• Kalpakkam
• Palk Bay
• Gulf of Mannar

These regions are particularly vulnerable due to their geography, pollution load, and oceanographic patterns.

🌐 Monitoring and Classification Tools

• INCOIS study introduced phytoplankton biomass thresholds to classify bloom intensity:
  • Likely to Bloom → Bloom → Intense Bloom → Extreme Bloom
• Enables early intervention and helps manage fisheries and aquaculture zones.

🛰️ Advancing Detection Technologies

• Region-specific bio-optical algorithms
• Enhanced satellite remote sensing
• These tools enable real-time alerts for fisheries, tourism operators, and coastal authorities.

📅 Seasonal Trends

• Southern Coast: Blooms peak during pre-southwest and northeast monsoon onset.
• Western Coast: Frequent during southwest and post-southwest monsoons.

🐟 Ecological & Economic Implications

• Threatens marine biodiversity and disrupts entire food chains.
• Affects fishing communities, coastal tourism, and shellfish aquaculture.
• Bloom-induced fish kills and toxin outbreaks create economic shocks for local livelihoods.

🔍 Call to Action

India needs robust, real-time monitoring, pollution control policies, and community education on algal bloom impacts. With climate change and industrial pollution acting as stress multipliers, coastal sustainability now hinges on early detection and rapid response.