Coral bleaching Archives - Saving Seafood

The world’s coral reefs are facing another mass bleaching event — maybe the biggest ever

April 16, 2024 — The world’s oceans are experiencing another global mass coral bleaching event because of unprecedented heat, scientists at the U.S. National Oceanic and Atmospheric Administration confirmed.

“This is the fourth time, on record, that coral bleaching has occurred simultaneously within all major ocean basins,” said Derek Manzello, ecologist and co-ordinator of NOAA’s Coral Reef Watch.

Bleaching — a ghostly discolouration, in stark contrast to vibrant colours found in reefs — can occur when corals are heat-stressed, expelling microscopic algae from within. The longer and hotter it gets, the more likely the corals will die, disrupting fragile ecosystems as well as the lives and livelihoods of people who depend on them.

But the full extent of damage is yet to come. Manzello is seeing an increase in affected reefs every week.

“If that trend continues, this will be the most spatially expansive, global bleaching event on record — in as little as a few weeks, potentially,” Manzello warned.

Read the full article at CBC

Exclusive: World on brink of fourth mass coral reef bleaching event, NOAA says

March 5, 2024 — The world is on the verge of a fourth mass coral bleaching event which could see wide swathes of tropical reefs die, including parts of Australia’s Great Barrier Reef, the U.S. National Oceanic and Atmospheric Administration (NOAA) said.

Marine biologists are on high alert following months of record-breaking ocean heat fuelled by climate change and the El Nino climate pattern.

“It’s looking like the entirety of the Southern Hemisphere is probably going to bleach this year,” said ecologist Derek Manzello, the coordinator of NOAA’s Coral Reef Watch which serves as the global monitoring authority on coral bleaching risk.

Read the full article at Reuters

Earth is likely just a decade a way from hitting 1.5°C of global warming — and scientists say it will be “catastrophic” for coral reefs

February 4, 2022 — The United Nations has warned the continued use of fossil fuels is hurtling the planet to 1.5°C of global warming, relative to 1850-1900 levels, a threshold that will result in “unprecedented” extreme weather events. According to new research, climate change will also result in coral bleaching that will be “catastrophic” for reefs, and potentially, the marine life that live around them.

Bleaching can occur from a change in ocean temperature, pollution, overexposure to sunlight and low tides. Any of these influences can stress coral and causes it to release the algae that live in its tissues. The loss of algae, corals’ primary food source, causes the coral to turn white and makes it more susceptible to disease.

Reefs are “among the most biologically diverse and valuable ecosystems on Earth,” serving as a vital resource for an estimated 25% of all marine life, which depend on reefs for their life cycles, according to the Environmental Protection Agency. Roughly half a billion people also depend on reefs for food, coastal protection, tourism and fisheries’ income.

But as climate change continues to negatively impact the planet, it will “overwhelm” those reefs, researchers said, and almost none of them will be able to escape a grave scenario.

Read the full story at CBS News

Bleached reefs still support nutritious fish, study finds

January 21, 2022 — Escalating ocean temperatures stemming from climate change are devastating the world’s tropical coral reefs. In response to the stress, corals, which are animals, sometimes unceremoniously jettison the algae that live within them. That expulsion drains the color from the reefs in what’s known as bleaching. In the severest cases, it can kill the coral, which need the algae to provide them with nutrients, oxygen and waste management.

At the same time, millions of people in the tropics eat fish that live on these reefs. And today, the widespread bleaching of tropical reefs, which is expected to continue as the Earth heats up, has thrown into question how those fisheries and the communities that depend on them for sustenance will respond.

Now, a new study published Jan. 6 in the journal One Earth has found that in certain circumstances, critical nutrients for human development found in reef fishes remain available even after mass bleaching has occurred.

“An important message here is that climate-impacted reefs can still provide some important ecosystem services, and therefore should still be considered in management plans and conservation,” said Camille Mellin, a quantitative ecologist at the University of Adelaide in Australia, who was not involved in the study.

Read the full story at Mongabay

Large Sections of Australia’s Great Reef Are Now Dead, Scientists Find

March 16, 2017 — The Great Barrier Reef in Australia has long been one of the world’s most magnificent natural wonders, so enormous it can be seen from space, so beautiful it can move visitors to tears.

But the reef, and the profusion of sea creatures living near it, are in profound trouble.

Huge sections of the Great Barrier Reef, stretching across hundreds of miles of its most pristine northern sector, were recently found to be dead, killed last year by overheated seawater. More southerly sections around the middle of the reef that barely escaped then are bleaching now, a potential precursor to another die-off that could rob some of the reef’s most visited areas of color and life.

“We didn’t expect to see this level of destruction to the Great Barrier Reef for another 30 years,” said Terry P. Hughes, director of a government-funded center for coral reef studies at James Cook University in Australia and the lead author of a paper on the reef that is being published Thursday as the cover article of the journal Nature. “In the north, I saw hundreds of reefs — literally two-thirds of the reefs were dying and are now dead.”

Read the full story at the New York Times

Hawaii Prepares Plan to Help Coral Recover From Bleaching

September 9, 2016 — KANEOHE, Hawaii — Hawaii officials proposed a series of steps to fight coral bleaching that’s threatening the state’s reefs, including new marine protected areas, limits on fishing and controlling polluted runoff from land.

Hawaii’s ocean temperatures have been rising as greenhouse gases in the atmosphere have increased, forcing corals to expel algae they rely on for food. Vast stretches of reef have turned white over the past two summers, increasing the risk that the coral will get sick and die. Some already have died.

It’s a serious concern for the health of the ocean because coral reefs provide habitat for fish and other marine life, scientists say. Severe or concurrent years of bleaching can kill coral reefs, as has been documented over the past two years in oceans around the world. Scientists expect a third year of bleaching to last through the end of 2016.

Bruce Anderson, the state Division of Aquatic Resources administrator, said addressing polluted runoff is difficult, noting it would cost millions of dollars to create artificial wetlands that would help control runoff. Fishermen in the past have also resisted moves to limit their catch.

But Anderson said the coral bleaching crisis presents an opportunity.

“We are going to have future bleaching events, and the water is going to get warmer. And it’s going to happen again and again,” he said Thursday. “So our challenge is to prevent the impacts of bleaching as much as we can and also to help the reefs recover.”

Read the full story from the Associated Press at ABC News

Coral bleaching threat increasing in western Atlantic and Pacific oceans

July 6, 2015 — As unusually warm ocean temperatures cover the north Pacific, equatorial Pacific, and western Atlantic oceans, NOAA scientists expect greater bleaching of corals on Northern Hemisphere reefs through October, potentially leading to the death of corals over a wide area and affecting the long-term supply of fish and shellfish.

While corals can recover from mild bleaching, severe or long-term bleaching kills corals. Even if corals recover, they are more susceptible to disease. Once corals die, it usually takes decades for the reef to recover — but recovery is only possible if the reefs are undisturbed. After corals die, reefs degrade and the structures corals build are eroded away, providing less shoreline protection and less habitat for fish and shellfish.

“The bleaching that started in June 2014 has been really bad for corals in the western Pacific,” said Mark Eakin, NOAA Coral Reef Watch coordinator. “We are worried that bleaching will spread to the western Atlantic and again into Hawaii.”

Earlier this year, NOAA’s Coral Reef Watch four-month Coral Bleaching Outlook accurately predicted coral bleaching in the South Pacific, including the Solomon Islands, Papua New Guinea, Nauru, Fiji, and American Samoa. It also recently predicted the coral bleaching in the Indian Ocean, including the British Indian Ocean Territory and the Maldives.

Coral bleaching occurs when corals are stressed by changes in environmental conditions such as temperature, light or nutrients. The coral expels the symbiotic algae living in its tissue, causing the tissue to turn white or pale. Without the algae, the coral loses its major source of food and is more susceptible to disease. Scientists note, however, that only high temperatures can cause bleaching over wide areas like those seen since 2014.

In fall 2014, Hawaii saw widespread coral bleaching for the first time since 1996. If corals in Hawaii bleach again this year, it would be the first time it happened in consecutive years in the archipelago.

Warmer ocean temperatures in 2014 also dealt a blow to coral nurseries in the Florida Keys, where scientists are growing threatened coral species to transplant onto local reefs. Coral reefs in Florida and the Caribbean have weathered repeated and worsening coral bleaching events for the past thirty years. The NOAA Coral Reef Watch monitoring team says that more bleaching so soon could spell disaster for corals that have yet to recover from last year’s stress.

“Many healthy, resilient coral reefs can withstand bleaching as long as they have time to recover,” Eakin said. “However, when you have repeated bleaching on a reef within a short period of time, it’s very hard for the corals to recover and survive. This is even worse where corals are suffering from other environmental threats, like pollution or overfishing.”

NOAA’s bleaching prediction for the upcoming months supports the findings of a paper published in the journal Science last week that examined the threat to marine ecosystems and ecosystem services under two different carbon dioxide emission pathways.

“The paper reports that even if humans limit the Earth’s warming to two degrees C (3.8 degrees F), many marine ecosystems, including coral reefs, are still going to suffer,” said Eakin, an author on the paper. “The increase we are seeing in the frequency and severity of bleaching events is part of why the climate models in that paper predict a dire future for coral reefs.”

The NOAA Coral Reef Watch program’s satellite data provide current reef environmental conditions to quickly identify areas at risk for coral bleaching, while its climate model-based outlooks provide managers with information on potential bleaching months in advance. The Coral Reef Watch mission is to utilize remote sensing and in situ tools for near-real-time and long term monitoring, modeling and reporting of physical environmental conditions of coral reef ecosystems.

The four-month Coral Bleaching Outlooks, based on NOAA’s operational Climate Forecast System, use NOAA’s vast collection of environmental data to provide resource managers and the general public with the necessary tools to help reduce effects of climate change and other environmental and human caused stressors.

Read the story from NOAA