By Science Advisor.  Excerpt: Researchers have declared  southern Florida’s  Acropora  coral colonies functionally extinct . The death knell for two reef-building species, elkhorn and staghorn, was the 2023 marine heatwave that brought temperatures above 31°C for almost 6 weeks. The event was the ninth mass coral mortality event for the region since 1987. “ This ecosystem is forever transformed ,” lead author Ross Cunning told  Nature . Conservation for these species “needs to fundamentally change.” Acropora  have made Florida and the Caribbean their home for the past 250,000 to 500,000 years. During the heatwave, they bleached in 98% to 100% of their southern Florida range, a process whereby the corals lose the symbiotic algae that feed them and give them color. Previously, scientists had attempted to reintroduce the corals in areas where they had declined. But with the reintroduced organisms now dead, the authors say that efforts must turn to breeding mor...

By Science Advisor.  Excerpt: According to 160 researchers from around the world, the planet has reached the first climate ‘tipping point’: Warmed waters have resulted in mass coral bleaching. “Already … coral reefs are crossing their thermal tipping point and experiencing unprecedented dieback,” the authors of the report noted. “We can no longer talk about tipping points as a future risk,” said one of the report’s lead authors. “This is our new reality.”...  See GLOBAL TIPPING POINTS  REPORT  |  READ MORE AT  NATURE . See also Eos article, As Seas Rise, Corals Can’t Keep Up . 

By Ferris Jabr, The New York Times.  Excerpt: On a hot February morning, that ship and two smaller companion barges — nicknamed Big Daddy and the Twins — roamed a bay within the Palm Islands cluster, off the northeastern coast of Australia. Each pumped seawater aboard, pressurized it and sprayed it into the air through hundreds of tiny nozzles arrayed on metal frames. Dense plumes of fog billowed from all three vessels, forming long white strands that eventually converged into a seamless cloak. ...Since 2016, Harrison and his colleagues have been investigating whether it is possible to reduce coral bleaching in the Great Barrier Reef by altering the weather above it. ...Theoretically, machine-generated fog and artificially brightened clouds can shade and cool the water in which corals live, sparing them much of that stress. ...The failure to prevent the planet’s average temperature from reaching 1.5 degrees Celsius above the preindustrial base line, and the progressively obvious an...

By Noam S. Vogt-Vincent et al.  Abstract: Past coral range expansions suggest that high-latitude environments may serve as refugia, potentially buffering coral biodiversity loss due to climate change. We explore this possibility for corals globally, .... Our simulations suggest that there is a mismatch between the timescales of coral reef decline and range expansion under future predicted climate change. Whereas the most severe declines in coral cover will likely occur within 40 to 80 years, large-scale coral reef expansion requires centuries. The absence of large-scale coral refugia in the face of rapid anthropogenic climate change emphasizes the urgent need to reduce greenhouse gas emissions and mitigate nonthermal stressors for corals, both in the tropics and in higher latitudes....  Full article at https://www.science.org/doi/10.1126/sciadv.adr2545 . 

By Elise Cutts , Science.  Excerpt: VIENNA—  Climate change is causing the oceans to get warmer and more acidic, making it harder for corals to build and maintain their mineral skeletons. Eventually, reefs will literally start to dissolve. It’s a grim fate, but one with a surprising silver lining. Research presented this week here at a conference of the European Geophysical Union shows  dissolving reefs will slow climate change , by boosting the oceans’ ability to soak up carbon dioxide (CO 2 ) out of the atmosphere. By the end of the century, the oceans could be absorbing up to 400 megatons of additional carbon per year. That’s more than the annual emissions of Australia or the United Kingdom. No one had actually calculated the magnitude of this “feedback” before, and it’s big enough that climate models need to account for it, says Jens Daniel Müller, a biogeochemist at ETH Zürich who wasn’t involved in the work. “Often we focus more on positive feedbacks, where the proc...

By Muhammed Fatih Sert et al, JGR Biogeosciences.  [Great example of the complexity of global systems!] Plain language summary: Cold seeps are geological features that release methane from the seabed to the water column. In oxygenated sea water column, seeping methane is consumed by specialized microbes that convert it into carbon dioxide. Although the increase in carbon dioxide can lead to ocean acidification, cold seeps are often found in the Hola trough of Northern Norway near cold-water corals (CWCs), which are vulnerable to changes in ocean acidity. This raises questions about how these features coexist in the same marine ecosystem and how they impact each other. We investigated the carbon exchange between cold seeps and CWCs by analyzing seawater samples. Our data on nutrients, organic matter, and microbial compositions implied cooccurring carbon processes such as methane oxidation and organic matter synthesis. Notably, cold seeps might support CWCs by producing dissolved or...

By Anupama Chandrasekaran , Eos/AGU.  Excerpt: When an intense marine heat wave sent ocean temperatures soaring in 2023 and 2024, coral reefs around the world bleached. New research on the Great Barrier Reef’s One Tree Island shows that more than 50% of surveyed coral colonies that bleached died of heat stress and starvation. And even heat-resistant corals weren’t immune. When corals are stressed by warm water, they can lose the algae that live in their tissues. This process turns the coral white, earning it the name “ coral bleaching .” Sometimes corals can recover, but if the stress is too intense, they die and eventually crumble into rubble and sand. “What we noticed in more recent times, when it gets really hot, they often die before they even fully bleach,” said marine biologist  Maria Byrne  at the University of Sydney....  Full article at https://eos.org/articles/great-barrier-reef-corals-hit-hard-by-marine-heat-wave .

By Caroline Hasler , Eos/AGU.  Excerpt: With global  sea levels  projected to rise 44 centimeters (17 inches) by the end of the century, atolls such as Aldabra—a  United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site  in Seychelles and home to the world’s largest population of giant tortoises—may be at risk of sinking into the ocean. A new  study , however, shows that despite consistently rising sea levels, most of Aldabra’s shoreline hasn’t changed since 1960. ...An atoll forms when corals attach to the margins of a volcanic island or platform in the ocean. Over time, the volcano is eroded and subsides into the sea, leaving a ring-shaped reef. Winds and waves deposit crushed coral from surrounding reefs on top of the ring, ultimately forming islands that rise above sea level. ...“Our research shows that Aldabra’s resilience to sea level rise is likely linked to its high protection status. This serves as a crucial les...

By Raymond Zhong  and  Mira Rojanasakul , The New York Times.  Excerpt: For the past two decades, scientists have been raising alarms about great systems in the natural world that warming, caused by carbon emissions, might be pushing toward collapse. These systems are so vast that they can stay somewhat in balance even as temperatures rise. But only to a point. Once we warm the planet beyond certain levels, this balance might be lost, scientists say. The effects would be sweeping and hard to reverse. Not like the turning of a dial, but the flipping of a switch. One that wouldn’t be easily flipped back. ...Mass Death of Coral Reefs. ...Abrupt Thawing of Permafrost. ...Collapse of Greenland Ice. ...Breakup of West Antarctic Ice. ...Sudden Shift in the West African Monsoon. ...Loss of Amazon Rainforest. ...Shutdown of Atlantic Currents....  \Full article at https://www.nytimes.com/interactive/2024/08/11/climate/earth-warming-climate-tipping-points.html .   

https://edition.cnn.com/2024/03/07/australia/mass-coral-bleaching-event-great-barrier-reef-intl-hnk-scn/index.html By Helen Regan , CNN.  Excerpt: Australia’s Great Barrier Reef is suffering another  mass bleaching event , the reef’s managers confirmed Friday, the result of soaring ocean temperatures caused by the global climate crisis and amplified by  El Niño . This is the seventh mass bleaching event to hit the vast, ecologically important but fragile site and the fifth in only eight years.... 

https://www.science.org/content/article/after-mass-coral-die-off-florida-scientists-rethink-plan-to-save-ailing-reefs By WARREN CORNWALL , Science.  Excerpt: Four years ago, the U.S. National Oceanic and Atmospheric Administration (NOAA) unveiled a $100 million coral moonshot. Over 2 decades, nearly half a million hand-reared coral colonies would be planted on seven ailing reefs in southern Florida, in a bid to revive them. ...Today, the project looks as ailing as the coral it was meant to save. A record-breaking underwater heat wave that swept the Caribbean and southern Florida in 2023 killed most of the transplanted colonies....

https://www.science.org/content/article/remote-pacific-island-clues-el-ninos-future-preserved-ancient-reefs By PAUL VOOSEN , Science.  Excerpt: ...The El Niño event, now at its peak, is driving weather extremes not just in Vanuatu, but all over the planet. Drought has struck Australia, as well as the Amazon, where intolerably hot waters have suffocated endangered pink dolphins. Rains have drenched Peru, spreading dengue, while warm waters intruding near its coast have disrupted the world’s largest anchovy fishery and forced the nation to cancel a lucrative fishing season. Those same warm waters accelerated Hurricane Otis, which devastated Acapulco and Mexico’s Pacific coast in October 2023. The effects have been truly global: By suppressing the Pacific’s ability to absorb heat from the atmosphere, El Niño helped make 2023 the  hottest year in history  by a huge margin. ... TWENTY THOUSAND YEARS AGO , at the peak of the last ice age, Earth was  6°C cooler than today ....

https://www.science.org/content/article/algal-outbreaks-around-world-are-crowding-out-corals By ELIZABETH PENNISI , Science.  Excerpt: Edmunds and colleagues  report today in Current Biology  that these algae are spreading rapidly in the Caribbean Sea and elsewhere, killing existing corals and crowding out new ones. The authors don’t have a solid explanation for the algae expansion, although warming waters or another aspect of climate change may be a driver. But they and others worry this new menace will hasten the demise of ecosystems already decimated in many places by multiple bleaching events, many also linked to climate change. ...These latest coral killers are a group of more than 140 hard to distinguish red algal species belonging to the Peyssonneliaceae family. Some scientists mistake them for coralline algae, which also form crusts on reefs but help promote growth of the living structures. Whereas coralline algae form thin, hard crusts that are pink or whiti...

https://www.plymouth.ac.uk/news/scientists-discover-deepest-known-evidence-of-coral-reef-bleaching By Alan Williams, University of Plymouth.  Excerpt: Scientists have discovered the deepest known evidence of coral reef bleaching, more than 90 metres below the surface of the Indian Ocean. The damage – attributed to a 30% rise in sea temperatures caused by the Indian Ocean dipole – harmed up to 80% of the reefs in certain parts of the seabed, at depths previously thought to be resilient to ocean warming. ...The findings, highlighted in a study published in  Nature Communications , were discovered by researchers from the University of Plymouth.... 

https://www.science.org/content/article/hard-working-farmers-corals-cultivate-and-eat-their-resident-algae By MOLLY RAINS , Science. Excerpt: ...How do vibrant corals flourish in often-barren ocean landscapes? Known as the Darwin Paradox, this mystery has continued to puzzle generations of oceanographers. A new study published today in Nature offers a solution. According to its authors,  corals make up for nutrient scarcity by harvesting and feeding on their resident algae , like hungry farmers....

https://www.science.org/content/article/shocking-levels-stress-marine-heat-wave-devastating-florida-s-corals By Warren Cornwall, Science.  Excerpt: Ocean water temperatures off southern Florida have spiked to record levels, with sea surface temperatures hovering at more than 2°C above typical seasonal peaks for the past few weeks. The heat wave threatens coral reef ecosystems already buffeted by years of ocean warming, disease, and pollution. Coral bleaching, in which heat-stressed coral polyps eject the symbiotic algae that live in their tissues and help nourish the coral, is already widespread this year off Florida’s coast. Corals are also shedding tissue and swiftly dying without going through bleaching.... [Interview with Ian Enochs, a coral reef ecologist with the National Oceanic and Atmospheric Administration, heads the coral program at the agency’s Atlantic Oceanographic and Meteorological Laboratory]

https://www.science.org/content/article/coral-reefs-are-home-greatest-microbial-diversity-earth By Elizabeth Pennisi, Science.  Excerpt: Findings may inform understanding of reefs’ resilience to environmental changes. ...Coral reefs, bastions of marine biodiversity because of the abundant fish, invertebrates, and algae they support, are also home to Earth’s greatest microbial diversity, according to a new estimate. ...an international team of researchers ...sequenced DNA from more than 5000 samples of three coral species, two fish species, and plankton. The team identified a half-billion kinds of microbes, mostly bacteria. ...the team reports today in Nature Communications. ...When the researchers extrapolated those findings to estimate the total reef microbial diversity across the Pacific, it was equivalent to Earth’s total, previously estimated microbial diversity. ...they expect this high microbial diversity can help the reefs be more resilient in the face of heat...

https://www.theguardian.com/environment/2023/apr/18/scientists-discover-pristine-deep-sea-galapagos-reef-teeming-with-life By Dan Collyns , The Guardian.  Excerpt: Scientists operating a submersible have discovered deep-sea coral reefs in pristine condition in a previously unexplored part of the  Galápagos marine reserve . Diving to depths of 600 metres (1,970ft), to the summit of a previously unmapped seamount in the central part of the archipelago, the scientists witnessed a breathtaking mix of deep marine life. This has raised hopes that healthy reefs can still thrive at a time when coral is in crisis due to record sea surface temperatures and ocean acidification. It also showed the effectiveness of conservation actions and effective management, they said. ...[Ecuador] is collaborating with its northern neighbours Panama, Costa Rica and Colombia on a  regional marine corridor initiative , which aims to protect and responsibly manage the ocean....

https://www.theguardian.com/environment/2022/nov/25/record-heat-over-great-barrier-reef-raises-fears-of-second-summer-of-coral-bleaching By  Graham Readfearn , The Guardian.  Excerpt: Ocean temperatures over parts of the  Great Barrier Reef  have reached record levels this month, sparking fears of a second summer in a row of mass coral bleaching. Data from the US government’s National Oceanic and Atmospheric Administration (Noaa) shows sea surface temperatures over the northern parts of the reef have been the highest for any November on a record going back to 1985. With the peak period for accumulated heat over the reef not expected until February, cooler weather conditions and cyclone activity before then could stave off a mass bleaching event. ...Last summer’s mass bleaching,  declared by the Great BarrierReef Marine Park Authority  (GBRMPA), was the first outbreak during a La Niña – a climate pattern that historically has kept ocean temperatures cool eno...

https://www.science.org/content/article/how-does-caribbean-fire-coral-thrive-others-vanish By Elizabeth Pennisi, Science Magazine.  Excerpt: Fire corals can be the bane of a scuba diver’s existence. An accidental brush against one can cause agonizing pain. But they also may help save Caribbean reefs, which have been plagued by hurricanes, global warming, disease, and an overabundance of algae. A long-term study has revealed that fire corals ( Millepora ) are thriving there even as other corals disappear and could help preserve some of the 3D environment that helps make reefs such great homes to fish and other organisms.…