Where Are Coastal Oceans Located?

Coastal oceans (or coastal zones) are the interface between land and open ocean. They extend from the shoreline (high-tide line) seaward to the edge of the continental shelf, typically at ~200 m depth (or the 200-m isobath). This includes:

• Estuaries, bays, lagoons, tidal flats.
• Continental shelf proper (neritic zone).
• Coral reefs, kelp forests, seagrass meadows.

Significance

• Productivity: 90% of global fish catch comes from coastal waters (nutrient runoff, upwelling, light penetration).
• Human use: 40% of humanity lives within 100 km of coast; ports, cities, tourism, energy.
• Climate regulation: Carbon sequestration (blue carbon), storm buffering, heat exchange.
• Biodiversity: Highest marine species density; nurseries, spawning grounds.

Threats

Eutrophication, hypoxia, habitat loss (mangroves, reefs), pollution, sea-level rise, ocean acidification, overfishing. Integrated Coastal Zone Management (ICZM) and Marine Protected Areas (MPAs) are key governance tools.