• Aral Sea
• Baltic Sea
• Bering Sea
• Black Sea
• Caribbean Sea
• Caspian Sea
• China Sea
• Dead Sea
• Mediterranean Sea
• North Sea
• Red Sea

• Marine environment
• Oceanography
• Oceans
• Sea level
• Sea water
• Surface water

• Science > Geography and oceanography

http://vocabularies.unesco.org/thesaurus/concept178