Why in the News?

Scientists reported on July 22 in Nature Geoscience that an unknown process is generating oxygen in the deep oceans, where photosynthesis is not possible due to the lack of light.

About the recent study:

• Discovery of Oxygen: Scientists reported an unknown process producing oxygen in the deep ocean, specifically in the abyssal zone, where photosynthesis is not feasible due to insufficient sunlight.
• Location of Study: The study was conducted in the Clarion-Clipperton Zone, located off Mexico’s west coast, which is known for having the highest concentration of polymetallic nodules.
• Oxygen Measurement: At a depth of 4 km, researchers observed unexpected increases in oxygen levels, sometimes tripling within two days, contrary to expectations of decreasing levels due to consumption by marine life.
• Source of Oxygen: The researchers hypothesized that the oxygen could be generated by polymetallic nodules, which may create electric charges that split water molecules, releasing oxygen. The nodules exhibited voltages up to 0.95 V, suggesting they could function like battery cells.

What is Deep-Sea Mining?

• Deep-Sea Mining: It involves extracting minerals from the ocean floor at great depths, targeting resources such as polymetallic nodules, polymetallic sulphides, and cobalt-rich ferromanganese crusts.

Economic and Strategic Importance of Deep-sea Mining:

• Resource Potential: The Clarion-Clipperton Zone holds substantial reserves, including 6 billion tonnes of manganese, and over 200 million tonnes each of copper and nickel, making it a significant target for future mining operations.
• International Contracts: The International Seabed Authority has granted exploration contracts to various contractors, including the Government of India, for deep-sea mining activities.

What is Dark Oxygen?

• “Dark oxygen” refers to the oxygen found in the deep ocean, specifically in regions where photosynthesis cannot occur due to the absence of sunlight. In such areas, known as the abyssal zone, oxygen levels are typically low and depend on global ocean circulation for replenishment.

Impact of Deep-Sea Mining

• Ecological Concerns:
  • Potential Damage: The recent findings highlight the potential risks of deep-sea mining to unique marine ecosystems that depend on ‘dark oxygen’. There is concern that mining could disrupt these ecosystems, leading to significant and possibly irreversible environmental impacts.
  • Historical Evidence: Previous experiments, such as the DISCOL Experiment, have shown long-term ecological damage from simulated mining activities, including reduced biodiversity and altered sedimentological profiles.
• Industry Response and Challenges:
  • Insurance Withdrawal: In response to growing concerns, major European insurance companies announced they would exclude deep-sea mining from their underwriting portfolios.
  • Sustainability Issues: The new discovery of ‘dark oxygen’ adds complexity to the debate on deep-sea mining. If sustainable practices are not implemented, such mining could become unfeasible due to its potential negative impacts on marine ecosystems.

Way forward: 

• Develop Comprehensive Environmental Regulations: The Government should establish and enforce robust environmental regulations and impact assessment protocols for deep-sea mining.
• Promote Sustainable Mining Practices: Need to invest in research and innovation to develop and implement technologies and methods that minimize environmental impact.

Mains PYQ: 

Q Coastal sand mining, whether legal or illegal, poses one of the biggest threats to our environment. Analyse the impact of sand mining along the Indian coasts, citing specific examples. (2019)

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