WAHINGTON — Federal scientists reported what they’ve dubbed a “coral graveyard” off the coast of Jarvis Island in the Pacific Remote Island Marine National Monument on Wednesday, saying an emergency undersea expedition found 95 percent of the coral dead.
It’s a phenomenon that’s sweeping the planet’s oceans, affecting different reefs at various levels, and is being attributed to multiple causes — including human and natural.
Even Kauai’s reefs have been touched, but the underlying source remains under debate.
In the case of the coral graveyard around Jarvis Island, located about 1,400 miles southwest of Hawaii, the coral was bleached in November and now scientists are saying it’s a “sea of dead coral.”
“There’s hardly anything left on the bottom in terms of the coral. It basically looks like a graveyard,” said the expedition chief scientist Bernardo Vargas-Angel of the National Oceanic and Atmospheric Administration. “The skeletons are still there but they are covered with algae.”
Federal scientists are blaming the El Nino for the massive die-off, the same natural event that sparked an upward trend ocean warming and sent 15 tropical cyclones spinning around Hawaii last year.
Woods Hole Oceanographic Institution scientist Anne Cohen, who is involved in the research on the Jarvis Island die-off, told the Associated Press a unique ocean current normally brings cooler water up from the deep and with it, a massive cache of marine life, but the area has become a virtual underwater desert.
Cohen said the water around the coral graveyard is about 7 degrees Fahrenheit warmer than normal and that warming water is mostly from El Nino.
On Kauai, scientists have also cited ocean warming and acidification as causes of coral death.
“The rising sea temperatures cause more coral to bleach and lose the algae that grows within the coral. This causes the coral to turn to a white color and the bleaching can cause the corals to die,” said Hanalei marine biologist Terry Lilley.
He explained the Earth goes through natural temperature cycles, but he said the cycles usually happen over thousands of years so the coral reefs have time to adapt.
“Now the cycles are happening within a short, 50-year timeframe, which is too quick for the corals to adapt, so we are likely to see a large die-off of our coral reefs, which will affect food supply, tourism and coastal erosion,” Lilley said.
Don Heacock, Kauai district aquatic biologist at the Department of Land and Natural Resources Division of Aquatic Resources, said there are human-generated threats to Kauai’s coral reefs as well.
He explained that in the United States, more than 65 percent of the rivers and streams are polluted with topsoil that carries nutrients and pollution into the ocean — and Kauai is no exception.
“The nutrients smother the coral and cause nutrient enrichment,” Heacock said. “Corals want to be in a nutrient-poor habitat; they need water where the sunlight penetration is to 100 feet.”
A study earlier this year found almost as much loss in an island called Kiribati, which is close to Jarvis Island, but NOAA coral reef coordinator Mark Eakin told the Associated Press the Jarvis death was worse.
“Just as I thought it couldn’t get any worse, it does,” Eakin said.
The Associated Press contributed to this report