Ocean water sprays into a packed boat of tourists. They hardly notice, as they sit on the edges of their seats, peering through the glass bottom in middle of the boat, which reveals a glowing blue ocean floor. The engine quiets and the boat comes to a slow drift, clearing the bubbles and waves rippling through the water, and bringing the scene below the boat into clearer view.
A vast mountain of coral reveals itself. Colorful fish dart through openings in the coral, escaping the jaws of predators. The boat takes about four minutes to pass across what seems like millions of corals, but this colony is actually all one animal. It’s the largest recorded rare blue coral colony in the world, measuring up to 14 meters in height.
“This has been growing for 3,000 years for it to get this big,” said tour guide Luka Nishihara.
The blue coral structure is located in Oura Bay in Henoko, in Japan’s Okinawa prefecture. The bay, which locals refer to as “Okinawa’s treasure,” is home to one of the most diverse marine ecosystems in the prefecture with 5,334 documented types of living things.
“There is no other place in Okinawa where there is such a great diversity of living things in such a small area,” said local environmentalist Chieko Matsui. “There are many ecosystems in this area that allow for many different species and organisms to thrive.”
Just a few hundred yards from the coral colony, the ocean’s crystal blue waters sweep out to a US military base where high construction cranes and ships are strewn about both land and sea.
The base includes a landing strip that stretches out into the bay in a v-formation, and which will stretch out across some about 157 hectares of land and water. A barrier of buoys surrounds the planned construction zone, with draped netting hanging down about 7 meters into the water.
Marine biologists and environmentalists say that the controversial construction project could disrupt ocean currents that corals need to survive, such as carrying in nutrients, filtering out sediment and debris, and maintaining the ecological balance within the bay. (The base also poses a risk to other marine wildlife, including the northernmost dugong population.)
“The netting might affect the entire bay because the current won’t come through its normal route,” said Mariko Abe, head of conservation at the Nature Conservation Society of Japan. “This construction blocks the current from coming in and bringing nutrients and fresh water.”
“In your body, if you stopped one artery, it’s going to have an impact on your whole body,” added Matsui. “And if these currents are disrupted, a lot of sediment that comes down from the land just stays there.”
Sedimentation associated with construction poses another threat. According to The Asia-Pacific Journal, the construction of the landing strip entails injecting three million tons of soil into the underwater construction zone.
Coral polyps retrieve and digest food, such as plankton, for the entire organism. Their tentacles have stinging cells that allow them to catch food and bring it to the mouth. From there, it moves into the gastrovascular cavity for digestion. This process builds the coral skeleton, which is how coral becomes larger and taller.
“If there is too much runoff from land in the water, the coral can’t operate well because it lacks food,” said Claudia Johnson, a professor of Geological Sciences at Indiana University. Sediment saturates the water and limits nutrients to corals— they’re ingesting sediment, rather than plankton.
In order to mitigate damage from the base project, the government promised to transplant many coral structures of varying species to other parts of the country. According to the Okinawa Prefectural Government’s fisheries division, it would be necessary to transplant 74,000 coral structures.
In a January appearance on public broadcaster NHK, Prime Minister Shinzo Abe that coral reefs from the construction site had already been transplanted. This claim has been met with criticism.
“Only eight or nine structures were transplanted,” said Mariko Abe. “They were moved because they were on the endangered list,” she added, referring to species like Porites okinawensis Veron, which is listed as vulnerable on the International Union for the Conservation of Nature red list alongside blue coral colonies.
Transplanting isn’t straightforward. The process — which involves cutting a piece of the living structure, moving it, placing it on a concrete base, and letting it grow in its new environment — can also be long and expensive. And currently, the success rate is rather low: There is about a 50/50 chance that the coral will survive after it is cut.
Nor is transplanting without downsides. Abe said that lack of nutrition and interference with currents, combined with removal of coral for transplanting, will affect the ecological balance within the bay. She added that the interdependent relationships between organisms would be irreplaceable.
“Suppose we transplant a coral that has a symbiotic relationship with a giant clam,” she said. “These two are friends that are living together, but the plan doesn’t include transplanting clams. So they lost their friendship together and with other creatures in the area. It is quite meaningless unless you transplant completely everything.”
Camp Schwab has been under construction for about 20 years and was set to replace Futenma, a highly controversial base in Ginowan, some 50 miles to the south. The project is viewed by the US military as essential to maintaining its presence in the region. Protestors have been fighting to stop construction of the base for years, in large part by holding sit-in demonstrations to block trucks carrying dirt into the site. Opposition is widespread. According to the Japan Times, a February non-binding, prefecture-wide referendum received more than 52 percent voter turnout, and 72 percent of voters said “no” to the relocation of the base to Henoko.
Major Andrew Aranda, a Marines spokesperson stationed in Camp Foster in Okinawa, said that landfill construction is not unusual in Okinawa, and that a negative perception of the military could be influencing public opinion. “It’s not the first time that the Japanese government has filled in land,” he said. “I would like to know if they make plans to move coral for construction outside of US purposes.”
Construction of Camp Schwab has been sluggish over the years. The seafloor, which Abe describes as “soft as mayonnaise,” has posed a challenge given the weight on the landing strip. Changes in construction plans require approval from the Okinawan government, which can be difficult to obtain.
Though the environment has already been affected, these delays have inspired hope among protesters that the plan might still be scrapped and the bay’s environment might be recovered. Protesters still actively sit in at constructions sites to further the conversation around the project.
Oura Bay’s rich oceanic diversity makes it unique to many other places in Okinawa. Matsui said tourists from Okinawa, Tokyo, and beyond come to experience its natural tranquility.
“A lot of people don’t see this kind thing,” said Matsui. “It’s kind of disappearing from Okinawa. So when they come here, it gives them a feeling of nostalgia for what Okinawa used to be like when they were a child.”
Matsui sits at a picnic table, the sound of children playing in a nearby schoolyard audible in the background as she recalls her experiences in anti-construction demonstrations. She would sit in front of the entrance to the site, blocking trucks from entering. Officers picked her up and carried her away each time, but she still went back to every protest.
Just steps away from her house is a beach where, on the left, towering rock formations and seashells are scattered across white sand. To the right, Camp Schwab can be seen in the distance.
She regularly takes her children to the beach where they play in sand and the water, picking up seashells and showing them to her. She said this is how she teaches them the importance of the nature in Oura Bay.
“This is a place for life to thrive,” she said. “I want to preserve this environment in a way that it can live easily and for people to live easily with it.”