Intro:
• Ocean currents = large-scale horizontal movement of surface waters.
• Water masses = large bodies of water with distinct temperature and salinity, moving vertically & horizontally in deep oceans.
• Both influence marine ecosystems & coastal dynamics differently.
1. Impacts of Ocean Currents:
A. Marine Life:
• Upwelling currents (Peru, Benguela): Bring nutrient-rich cold water → boosts plankton → rich fisheries (e.g., sardines off Peru).
• Warm currents (Gulf Stream): Increase water temperature → influence migration, breeding (e.g., cod fisheries in N. Atlantic).
• Converging currents: Promote biodiversity hotspots (e.g., Japan – Oyashio & Kuroshio meet).
B. Coastal Environment:
• Erosion & Sedimentation: Longshore drift shaped by currents alters coasts (e.g., Chennai coast erosion).
• Climate influence: Warm currents raise coastal temperatures (e.g., UK warmer due to Gulf Stream).
• Cyclogenesis: Warm currents intensify cyclones (e.g., Bay of Bengal).
2. Impacts of Water Masses:
A. Marine Life:
• Thermohaline circulation: Transports oxygen to deep oceans → sustains deep-sea life.
• Cold bottom waters (AABW, NADW): Maintain habitat stability for deep-sea organisms.
B. Coastal Environment:
• Minimal direct impact compared to surface currents.
• Indirect effects: Long-term climate regulation via deep ocean circulation (e.g., El Niño impacts).
Conclusion:
• Ocean currents have direct, dynamic impacts on coastal climate, fisheries & erosion.
• Water masses influence deep-sea ecosystems & long-term oceanic and climate stability.
• Both are integral to ocean health & coastal sustainability.
