by University of Erlangen-Nuremberg Nov 2020, in ScienceDaily
Coral reefs are hotspots of biodiversity. As they can withstand heavy storms, they offer many species a safe home, and at the same time, they protect densely populated coastal regions as they level out storm-driven waves. However, how can these reefs that are made up of often very fragile coral be so stable? A team of researchers from Friedrich-Alexander Universität Erlangen-Nürnberg (FAU) and the University of Bayreuth have now discovered that a very specific type of ‘cement’ is responsible for this — by forming a hard calcareous skeleton, coralline red algae stabilise the reefs, and have been doing so for at least 150 million years.
The wide variety of life they support is immediately apparent on images of tropical coral reefs. Their three-dimensional scaffolding provides a habitat for a large number of species. However, the skeletons of the coral are often so fragile that they would not be able to withstand heavy storms by themselves. Even if scientists have long suspected that coralline red algae provide support to reefs with their calcareous skeletons, this is the first time that this link has been proven.
Coralline red algae have been supporting coral reefs for at least 150 million years
The researchers from FAU and the University of Bayreuth were able to prove this supporting function by analysing more than 700 fossilised reefs from 150 million years of the Earth’s history. ‘The coralline red algae form a calcareous skeleton and cement the coral reefs together,’ explains Dr. Sebastian Teichert from the Chair of Palaeoenvironmental Research at FAU. ‘However, several crises over the course of millions of years have limited their capacity to do so.’
Successful adaptive strategies against plant grazers
by B. Bruno, May 22, 2020 in ClimateChangeDispatch
Some coral reefs are adapting to warming ocean temperatures by making their own sunscreen in the form of bright neon colors — a strategy that invites coral animals to return to reefs and is seen as a critical adaptation to maintain healthy coral reefs around the world.
In a study published Thursday in the journal Current Biology, researchers at the University of Southampton detail a series of controlled laboratory experiments they conducted at their coral aquarium facility.
In the experiments, “colorful” coral bleaching events cause coral to produce a layer of vibrant sunscreen which encourages the coral animals vital to a mutually beneficial “symbiosis” relationship to return to coral habitats they abandon due to the effects of warming oceans.
The colorful adaptation could prove vital for overcoming the fatal coral bleaching incidents that have threatened coral reefs worldwide.
But the colorful coral bleaching – rather than the white skeleton exposure of common coral bleaching events – is believed to take place due to mild ocean warming or disturbances in their nutrient environment, rather than extreme events.
Colorful bleaching occurred between this past March and April in some areas of the Great Barrier Reef, suggesting some patches of the world’s largest reef system may have better recovery prospects than others.
by P. Homewood, March 21, 2020 in NotaLotofPeopleKnowThat
Bullet Point Summary:
- Coral thrive in warm water, not cold water.
- Recent warming has allowed coral to expand their range poleward, while still thriving near the equator.
- Coral has existed continuously for the past 40 million years, surviving temperatures and carbon dioxide levels significantly higher than what is occurring today.
- The primary causes of coral bleaching include oxybenzone (a chemical found in sunscreen), sediment runoff from nearby coastal lands, and cold temperatures like those recorded in 2010 off the Florida coast.
Short Summary: Coral require warm water, not cold water, to live. Coral cannot live outside of tropical or subtropical waters. (See Figure 1.) As Earth continues to modestly warm, coral are extending their range toward the poles while still thriving at and near the equator. The primary reasons for bleaching events include sediment pollution from nearby coastal lands, chemicals found in sunscreen, and cold temperature events. Coral have existed continuously for the past 40 million years. Coral survived and thrived when temperatures were significantly warmer than they are today.
Figure 1: Coral Reef Locations
Continuer la lecture de Climate At A Glance Factchecks–Coral Reefs
by University of Queensland, August 7, 2019 in GWPF
The discovery was made by University of Queensland and CSIRO researchers investigating whether corals that split their spawning over multiple months are more successful at spreading their offspring across different reefs.
Dr Karlo Hock, from UQ’s School of Biological Sciences, said coral mass spawning events are one of the most spectacular events in the oceans.
“They’re incredibly beautiful,” Dr Hock said.
“On Australia’s Great Barrier Reef, all coral colonies typically spawn only once per year, over several nights after the full moon, as the water warms up in late spring.”
Study co-author Dr Christopher Doropoulos from the CSIRO Oceans & Atmosphere said sometimes however, coral split their spawning over two successive months.
“This helps them synchronise their reproduction to the best environmental conditions and moon phases,” he said.
“While reproductive success during split spawning may be lower than usual because it can lead to reduced fertilisation, we found that the release of eggs in two separate smaller events gives the corals a second and improved chance of finding a new home reef.”
The research team brought together multi-disciplinary skills in modelling, coral biology, ecology, and oceanography, simulating the dispersal of coral larvae during these split spawning events, among the more than 3800 reefs that make up the Great Barrier Reef.
by Jim Steele, April 2, 2019 in WUWT
Good news continues to accumulate regards corals’ ability to rapidly adjust to changing climates. The view of coral resilience has been dominated by the narrative of a few scientists. In the 1990s they advocated devastating consequences for coral reefs due to global warming, arguing coral cannot adapt quickly enough. Since the Little Ice Age ended, they believed rising ocean temperatures had brought coral closer to a “bleaching threshold”, a more or less fixed upper temperature limit above which corals cannot survive. Their model predicted the speed of recent global warming “spells catastrophe for tropical marine ecosystems everywhere”. Their assertions that “as much as 95% of the world’s coral may be in danger of being lost by mid-century” was guaranteed to capture headlines and instill public fear. However, a growing body of scientific research increasingly casts doubts on such alarming predictions. Unfortunately, that good news gets much less attention.
A recent peer-reviewed paper titled A Global Analysis of Coral Bleaching Over the Past Two Decades (Sully 2019) compared 20 years of ocean temperatures at which coral bleaching was initiated. From 1998 to 2006, the average sea surface temperature that initiated bleaching was 82.6 °F. But that temperature limit proves not to be “fixed” as earlier researchers incorrectly believed. From 2007 to 2017 the average temperature limit that initiated bleaching was higher, 83.7 °F. This indicates coral have been rapidly adapting to warmer regional climates much faster than once believed.
by Peter Ridd, December 26, 2018 in GWPF
Scientists from James Cook University have just published a paper on the bleaching and death of corals on the Great Barrier Reef and were surprised that the death rate was less than they expected, because of the adaptability of corals to changing temperatures.
It appears as though they exaggerated their original claims and are quietly backtracking.
To misquote Oscar Wilde, to exaggerate once is a misfortune, to do it twice looks careless, but to do it repeatedly looks like unforgivable systemic unreliability by some of our major science organisations.
The very rapid adaptation of corals to high temperatures is a well-known phenomenon; besides, if you heat corals in a given year, they tend to be less susceptible in the future to overheating. This is why corals are one of the least likely species to be affected by climate change, irrespective of whether you believe the climate is changing by natural fluctuations or because of human influence.
Corals have a unique way of dealing with changing temperature, by changing the microscopic plants that live inside them. These microscopic plants, called zooxanthellae, give the coral energy from the sun through photosynthesis in exchange for a comfortable home inside the coral. When the water gets hot, these little plants effectively become poisonous to the coral and the coral throws them out, which turns the coral white — that is, it bleaches.
by Nick Visser, December 10, 2018 in Huffpost
Last year’s oceanic heat wave wasn’t as destructive as one the year before, scientists said.
The Great Barrier Reef fared better during an oceanic heat wave last year than during sizzling weather a year earlier that caused hundreds of miles of corals to bleach, according to a study published Monday that suggests the massive structure may be growing more tolerant to climate change.
The report in the journal Nature Climate Change analyzed how corals along the Great Barrier fared in back-to-back mass bleaching events. The reef ― a UNESCO World Heritage Site and the largest living structure on the planet ― was cooked by overheated seawater in 2016 and again in 2017, with images of sickly white coral horrifying people around the globe.
See also here
by AMERICAN INSTITUTE OF BIOLOGICAL SCIENCES, February 2, 2017 in WUWT
A survey of 97 coastal ecosystem experts revealed impacts of climate disturbance but also instances of resilience in all ecosystem types evaluated and at multiple locations worldwide …
by Jennifer Marohasy, June 19, 2018
Dr Peter Ridd has taken James Cook University to court protesting his sacking for what he says is, primarily, speaking-out about the lack of quality assurance in Great Barrier Reef science.
Dr Ridd spoke out initially about there being no quality assurance of Great Barrier Reef science – science that is arguably misused to secure billions of dollars of tax-payer funding. When the University tried to stop Dr Ridd doing this, Dr Ridd spoke out against University management – making all the documentation public including on his new website.
by Nicola Jones, January 11, 2011 in Nature
Corals around Japan are fleeing northwards, according to a new study. One type has been spotted ‘sprinting’ at 14 kilometres a year, thanks to a lift from ocean currents. That means ocean ecosystems could shift rapidly in the face of climate-change impacts such as warming seas, the authors say.
by University of Sydney, May 28, 2018 in ScienceDaily
Over millennia, the reef has adapted to sudden changes in environment by migrating across the sea floor as the oceans rose and fell.
The study published today in Nature Geoscience, led by University of Sydney’s Associate Professor Jody Webster, is the first of its kind to reconstruct the evolution of the reef over the past 30 millennia in response to major, abrupt environmental change.
The 10-year, multinational effort has shown the reef is more resilient to major environmental changes such as sea-level rise and sea-temperature change than previously thought but also showed a high sensitivity to increased sediment input and poor water quality. (…)
by James Spry, April 19, 2018 in Climatism
A new study, published in Nature by serial reef alarmist Prof Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, examines the link between the level of heat exposure from the 2015/16 super El Niño, “resulting in coral bleaching and ultimately coral death.“
See aslo here
by University of California – Irvine, April 26, 2018 in ScienceDaily
By taking a closer look, scientists find resilience in face of heat stress.
Coral reef bleaching is stark evidence of the damage being inflicted by global climate change on marine ecosystems, but a research team has found some cause for hope. While many corals are dying, others are showing resilience to increased sea surface temperatures, pointing to possible clues to the survival and recovery of these vitally important aquatic habitats (…)
See aslo here
by B. Friedlander, January 25, 2018 in CornellChronicle
“Plastics make ideal vessels for colonizing microscopic organisms that could trigger disease if they come into contact with corals,” Lamb said. “Plastic items – commonly made of polypropylene, such as bottle caps and toothbrushes – have been shown to become heavily inhabited by bacteria. This is associated with the globally devastating group of coral diseases known as white syndromes.”
When plastic debris meets coral, the authors say, the likelihood of disease increases from 4 to 89 percent – a 20-fold change. The scientists estimate that about 11.1 billion plastic items are entangled on reefs across the Asia-Pacific region, and that this will likely increase 40 percent over the next seven years.
by Cornell University, January 25, 2018 in ScienceDaily
Plastics make ideal vessels for colonizing microscopic organisms that could trigger disease if they come into contact with corals,” Lamb said. “Plastic items — commonly made of polypropylene, such as bottle caps and toothbrushes — have been shown to become heavily inhabited by bacteria
in Friends of Science, December 2017
|This study gives irrefutable evidence on the persistence of atoll reef islands in French Polynesia over the last five decades, as 92% of the 111 islands studied exhibited either areal stability or expansion since the 1960s. Only 8% of the 111 islands showed contraction in area. Tropical cyclone waves contributed to island upward growth, which reached up to 1 m in places, through the transfer of sediments up onto the island surface.
by P. Blanchon et al., October 12, 2017 in Front.Earth.Sci
Predicting the impact of sea-level (SL) rise on coral reefs requires reliable models of reef accretion. Most assume that accretion results from vertical growth of coralgal framework, but recent studies show that reefs exposed to hurricanes consist of layers of coral gravel rather than in-place corals. New models are therefore needed to account for hurricane impact on reef accretion over geological timescales
by Alan Jones, interviews peter Ridd, July 28, 2017 in JoNova
Corals have a little thermometer built in them, when you take a core of them from many years ago we know what the temperature of the water was back when Captain Cook sailed up the coast, it was actually about the same temperature then. It was colder 100 years ago, but it has recovered from that. The temperatures on the reef are not even significantly warmer than average on a hundred year timescale.
Corals that bleach in one year will be less susceptible to bleaching in following years
by James Cook University and Université Catholique de Louvain, July 3, 2017, in ScienceDaily
Professor Wolanski said the study was subjective to the extent that there was a lack of oceanographic field data in the Great Barrier Reef itself for the 2016 el Nino event. By contrast, the amount of oceanographic field data in the Torres Strait and the northern Coral Sea was very good.
“What we presented is our best-informed attempt to reveal the mechanisms involved in causing the event, based on the available oceanographic data combined with the existing body of knowledge on the water circulation in and around the Torres Strait/Northern Great Barrier Reef region.”
by Clives James, The Australian in GWPF, June 6, 2017
Actually, a more illustrative starting point for the theme of the permanently imminent climatic apocalypse might be taken as August 3, 1971, when The Sydney Morning Herald announced that the Great Barrier Reef would be dead in six months.
After six months the reef had not died, but it has been going to die almost as soon as that ever since, making it a strangely durable emblem for all those who have wedded themselves to the notion of climate catastrophe.
by N.R. Evensen and P.J. Edmunds, 2017, J. Exp. Biology
Regardless of the actual mechanism responsible for the densely aggregated corals to maintain calcification rates in the face of ocean acidification, the study of Evensen and Edmunds, in their words, offers “a compelling case for differential densities of branching coral colonies (i.e. aggregation types) mediating the sensitivity of coral communities in at least some habitats” and it further supports “recent indications that neighboring organisms, such as conspecific coral colonies in the present example, can create small-scale refugia from the negative effects of ocean acidification” And that is more good news for those concerned about the future health of these important marine ecosystems.
by Rutgers University, June1, 2017 in SienceDaily
Stony corals may be more resilient to ocean acidification than once thought, according to a Rutgers University study that shows they rely on proteins to help create their rock-hard skeletons.
“The bottom line is that corals will make rock even under adverse conditions,” said Paul G. Falkowski, a distinguished professor who leads the Environmental Biophysics and Molecular Ecology Laboratory at Rutgers University-New Brunswick. “They will probably make rock even as the ocean becomes slightly acidic from the burning of fossil fuels.”
See also here
by Eghbert Elvan Ampou et al., 2017
The clear link between mortality and sea level fall also calls for a refinement of the hierarchy of El Niño impacts and their consequences on coral reefs.
by Smithsonian Tropical Research Institute, March 21, 2017
Dead zones affect dozens of coral reefs around the world and threaten hundreds more according to a new study. Watching a massive coral reef die-off on the Caribbean coast of Panama, they suspected it was caused by a dead zone — a low-oxygen area that snuffs out marine life — rather than by ocean warming or acidification.
Journal Reference: Andrew H. Altieri, Seamus B. Harrison, Janina Seemann, Rachel Collin, Robert J. Diaz, Nancy Knowlton. Tropical dead zones and mass mortalities on coral reefs. Proceedings of the National Academy of Sciences, 2017; 201621517 DOI: 10.1073/pnas.1621517114