Subject: World Geography

The alarming proliferation of marine dead zones represents one of the most severe threats to ocean ecosystems, characterized by oxygen-depleted waters that create vast underwater deserts devoid of marine life. These zones, particularly prominent in the Arabian Sea and Bay of Bengal, have far-reaching consequences for marine biodiversity and human communities.

Major Consequences of Dead Zones

Impact on Marine Biodiversity

• Mass Migration: Marine species are forced to relocate, disrupting established ecological patterns and food chains.
• Species Extinction: Bottom-dwelling organisms face severe threats due to oxygen depletion, as evidenced by the 2025 study in the western Bay of Bengal showing areas devoid of macro-organisms.
• Biodiversity Loss: Only highly adaptable species like Parascombrops pellucidus survive in these hostile environments, leading to reduced species diversity.

Economic Implications

• Fisheries Collapse: India's fishery sector faces an annual economic loss of $2.2 billion due to water pollution and dead zones.
• Loss of Livelihoods: Coastal communities dependent on fishing face severe economic hardships due to declining fish populations.
• Food Security Concerns: Reduction in fish catch affects protein security for coastal populations.

Environmental Consequences

• Disrupted Nutrient Cycles: Dead zones alter natural nutrient cycling in marine ecosystems.
• Habitat Destruction: Critical marine habitats like coral reefs and seagrass beds face degradation.
• Climate Change Feedback: Dead zones contribute to increased methane emissions, further exacerbating global warming.

Public Health Impact

• Water Quality: Contaminated marine waters lead to health issues, causing economic losses of $246 million annually from waterborne diseases in India.
• Seafood Safety: Toxic algal blooms in dead zones can contaminate seafood, posing risks to human health.

The expansion of dead zones, particularly in regions like the Bay of Bengal (60,000 km²) and the Persian Gulf (7,000 km²), demands urgent attention through integrated coastal management approaches and reduction in nutrient pollution. Implementation of Sustainable Development Goal 14 (Life Below Water) and strengthening of marine protected areas are crucial steps toward addressing this critical environmental challenge.