Military bases and submarines: What it's like to dive in the South China Sea

Story highlights

  • Greg Asner went diving in the South China Sea to survey coral reefs
  • He and his team found 70% loss of reef cover on atolls with military bases

Greg Asner is a professor at the Department of Global Ecology at the Carnegie Institution for Science. He conducted a field and satellite survey in the Spratly Islands last year.

(CNN)The Spratly Islands are a nebula of biological wonder -- an archipelago of atolls and reefs that support 600 coral species and 6,000 fish species -- including huge schools of batfish, bumphead parrotfish, scalloped hammerhead sharks, and dolphins.

But they are also located in one of the most contested stretches of water in the world -- the South China Sea -- and the island chain is now is home to some 15 military bases.
    China, Vietnam, Taiwan, Malaysia and the Philippines have all reclaimed land in the Spratlys and built airstrips that can accommodate military aircraft but it's China's island-building that has grabbed the most headlines.
      Since the beginning of 2014, China reclaimed more than 3,000 acres of land centering on seven reefs, according to the US. By contrast, the other claimants have reclaimed just 100 acres over 45 years.
      In 2016, I ventured into the Spratlys to better understand the ecological cost of this conversion process and found a devastating impact on coral reefs.

      Ring of life

      When an atoll is converted to a military base, it is dredged and the corals are used as a foundation for runways, buildings, armaments, and other installations.
      Another Carnegie scientist and I visited one of the atolls controlled by Malaysia in the southeast corner of the archipelago.
      Called Swallow Reef, the atoll is a ring of life that drops off more than 3,000 meters (10,000 feet) into deep ocean.
      Swallow Reef drops off more than 3,000 meters (10,000 feet)  into deep ocean.
      We combined rapid underwater surveys with a new class of satellite imaging provided by a company called Planet. Planet op