Why in the news?

• US scientists discovered the presence of offshore aquifers in the Atlantic Ocean from New Jersey to Maine.

Offshore Aquifers

• Definition: Offshore aquifers are bodies of porous rock or sediment containing freshwater located beneath the sea floor.
• Formation:
  • Pleistocene Glaciation: During ice ages, sea levels were lower, and rainwater seeped into coastal sediments. As sea levels rose, the aquifers were submerged.
  • Hydrological Processes: Freshwater flows from land through permeable sediments into offshore aquifers, trapped by confining layers.
• Global Distribution:
  • Found along continental shelves worldwide (e.g., U.S. Atlantic coast, Australia, South Africa, and parts of India).
  • Estimated to contain ~500,000 km³ of freshwater, mostly brackish but usable after treatment.
• Significance:
  • Water Security
    • Critical for coastal regions facing groundwater depletion (India, Middle East, Africa).
    • Alternative source of freshwater for drought-prone and arid regions.
  • Climate Change Resilience
    • Provides backup during rising sea-level induced salinisation of coastal aquifers.
  • Scientific Importance
    • Offers insights into paleo-climate and hydrological cycles.
• Challenges:
  • Extraction Difficulty: Located hundreds of meters below seabed, requiring advanced drilling & desalination.
  • Environmental Risks: Over-extraction could cause saline intrusion and ecological imbalance.
  • Legal Issues: Not clearly governed under UNCLOS (Law of the Sea) – disputes possible.
  • Economic Cost: High cost of exploration, drilling, and treatment compared to traditional water sources.