Coral bleaching event now biggest in history – and about to get worse

US weather agency says bleaching is now the most widespread on record and is likely to continue for unprecedented third year
Michael Slezak The Guardian 20 Jun 16;

The coral bleaching event sweeping the globe and destroying vast tracts of valuable coral reef is now officially the most widespread in recorded history, and is likely to continue for an unprecedented third year, according to the US weather agency.

For the coming four months, National Oceanographic and Atmospheric Administration says its forecasts show warm ocean temperatures are expected to cause bleaching in the northern hemisphere, including around Hawaii, Micronesia, the Florida Keys and Puerto Rico.

“All northern hemisphere US-coral reefs are on alert for coral bleaching this year,” said Mark Eakin, coordinator of Coral Reef Watch at Noaa. “If we see bleaching in Florida or Hawaii this year it will be three years in a row.”

Coral in every major reef region has already experienced severe bleaching. About 93% of the reefs on Australia’s Great Barrier Reef have been affected, and almost a quarter of the reef on the 2,300km stretch is now dead.

Hawaii and the Florida Keys, which will probably be hit by bleaching in the coming months, have been affected twice already, in mid-2014 and mid-2015. Reefs in the Indian Ocean around the Maldives and Western Australia have suffered severe bleaching, as have those in the rest of the Pacific, the Red Sea and the Caribbean.

Although the bleaching event was already the longest in recorded history and was predicted to run past the middle of the year, Noaa’s latest climate model-based forecasts now suggest it will run at least through to the end of 2016.

Coral bleaches when water temperatures are a couple of degrees above the normal summer maximum for longer than about two weeks. Climate change has caused global sea surface temperatures to rise by about 1C over the past century, pushing corals closer to their bleaching threshold. A strong El Niño, as well as other weather phenomena, raised the temperature further this year.

“It’s time to shift this conversation to what we can and are doing to conserve these amazing organisms in the face of this unprecedented global bleaching event,” said the director of Noaa’s coral reef conservation program, Jennifer Koss.

Coral reefs can often recover from bleaching when there is enough time between bleaching events, provided there aren’t too many other stressors, such as overfishing and water pollution.

Relieving the local stressors was important, but not enough, Koss said. “Globally, we need to better understand what actions we all can take to combat the effects of climate change.”

Noaa tracks the water temperature from satellite data and uses that to estimate the probable bleaching it will cause. Eakin said the information was then given to scientists and managers on the ground.

“The biggest bleaching threat over the next six months is to the reefs in two US freely associated states: Palau and the Federated States of Micronesia,” he said. “Islanders there are very dependent on their coral reefs and diving tourism is a major contributor to their economies. This event may have major ecological and economic impacts on those islands.”

He added: “It is crucial that scientists and the public continue in-water monitoring to track the actual extent and severity of the bleaching it causes.”

Global coral bleaching event expected to last through 2016
CALEB JONES Associated Press Yahoo News 21 Jun 16;

HONOLULU (AP) — After the most powerful El Nino on record heated the world's oceans to never-before-seen levels, huge swaths of once vibrant coral reefs that were teeming with life are now stark white ghost towns disintegrating into the sea.

And the world's top marine scientists are still struggling in the face of global warming and decades of devastating reef destruction to find the political and financial wherewithal to tackle the loss of these globally important ecosystems.

The International Coral Reef Symposium convened Monday to try to create a more unified conservation plan for coral reefs.

Federal officials said Monday the global coral bleaching event that began in 2014 with a super-charged El Nino is ongoing and is now the longest-lasting and largest such event ever recorded.

National Oceanic and Atmospheric Administration officials said that the event is expected to continue for its third year, lasting at least until the end of 2016.

While forecasters predict a change from El Nino to La Nina conditions, much of the warm water will remain in place or shift to other regions throughout the rest of the year.

All of the reef areas in the northern hemisphere — which includes almost all of the reefs in the United States — will experience another season of bleaching, said Mark Eakin, coordinator for NOAA's Coral Reef Watch program. Eakin noted that places like Hawaii and Florida have already had two consecutive years of severe bleaching, and a third is reason for concern.

"It's not likely to be as severe as last year according to the models, but time will tell," said Eakin. "It's very important for the managers to be ready for the fact that this may be a third year of bleaching."

Consecutive years of coral bleaching have led to some of the most widespread mortality of reefs on record, leaving scientists in a race to save them. While bleached coral often recovers, multiple years weakens the organisms and increases the risk of death.

Eakin said Palau and other Pacific islands in Micronesia face the biggest threats as warm waters push westward. Those islands are dependent on their reefs for both sustenance and the economic value of tourism.

"Local conservation buys us time, but it isn't enough," said Jennifer Koss, NOAA's Coral Reef Conservation Program director. "Globally, we need to better understand what actions we all can take to combat the effects of climate change."

"What we have to do is to really translate the urgency," said Ruth Gates, president of the International Society for Reef Studies and director of the Hawaii Institute of Marine Biology.

Gates, who helped organize the conference in Honolulu for more than 2,000 international reef scientists, policymakers and others, said the scientific community needs to make it clear how "intimately reef health is intertwined with human health."

She said researchers have to find a way to implement large scale solutions with the help of governments.

Researchers have achieved some success with projects such as creating coral nurseries and growing forms of "super coral" that can withstand harsher conditions. But much of that science is being done on a very small scale with limited funding.

Bob Richmond, director of the University of Hawaii's Kewalo Marine Laboratory, said the problems are very clear: "overfishing of reef herbivores and top predators, land-based sources of pollution and sedimentation, and the continued and growing impacts of climate change."

While reefs are major contributors to many coastal tourist economies, saving the world's coral isn't just about having pretty places for vacationers to explore. Reefs are integral to the overall ecosystem and are an essential component of everyday human existence.

Reefs not only provide habitat for most ocean fish consumed by humans, but they also shelter land from storm surges and rising sea levels. Coral has even been found to have medicinal properties.

In one project to help save reefs, researchers at the University of Hawaii's Institute of Marine Biology have been taking samples from corals that have shown tolerance for harsher conditions in Oahu's Kaneohe Bay and breeding them with other strong strains in slightly warmer than normal conditions to create a super coral.

The idea is to make the corals more resilient by training them to adapt to tougher conditions before transplanting them into the ocean.

Another program run by the state of Hawaii has created seed banks and a fast-growing coral nursery for expediting coral restoration projects.

Most of Hawaii's species of coral are unlike other corals around the world in that they grow very slowly, which makes reef rebuilding in the state difficult. So officials came up with a plan to grow large chunks of coral in a fraction of the time it would normally take.

Coral reefs have almost always been studied up close, by scientists in the water looking at small portions of reefs.

But NASA's Jet Propulsion Laboratory is taking a wider view, from about 23,000 feet above. NASA and other scientists recently launched a three-year campaign to gather new data on coral reefs worldwide. They are using specially designed imaging instruments attached to aircraft.

"The idea is to get a new perspective on coral reefs from above, to study them at a larger scale than we have been able to before, and then relate reef condition to the environment," said Bermuda Institute of Ocean Sciences' Eric Hochberg, principal investigator for the project.

If the scientific community and the world's governments can't come together to address coral's decline, one of earth's most critical habitats could soon be gone, leaving humans to deal with the unforeseen consequences.

"What happens if we don't take care of our reefs?" asked Gates. "It's dire."

No comments:

Post a Comment