Guest post by David Middleton
This gem was in my morning email from the American Association for the Advancement of Science in America…
The Great Barrier Reef has had five near-death experiences in the past 30,000 years
By Katie LanginMay. 28, 2018 , 11:00 AM
Thirteen thousand years ago, as the last ice age ended, entire stretches of Australia’s Great Barrier Reef perished. Rising sea levels blanketed the world’s largest collection of corals with sediment coming off the newly inundated land, blocking the sunlight corals need to grow. The reef eventually recovered, but it took hundreds to thousands of years. This near death and eventual resurrection wasn’t a one-off, according to a new study that reveals the reef’s shifting boundaries over geological time. It’s a tale that has played out five times over the past 30,000 years—and it may be happening again today.
The study “holds some really important lessons” for understanding how resilient corals are in the face of change, and how quickly they recover after catastrophic events, says Kim Cobb, a paleoclimatologist at the Georgia Institute of Technology in Atlanta, who wasn’t involved in the work. Today’s rate of sea level rise is moderate—about 10% of the rate 13,000 years ago—but going forward it may accelerate dramatically, she says.
The reef migrated up and down during that time, the team found, closely tracking changes in sea level at a rate of up to 20 vertical meters per thousand years.
Scientists have long wondered where the Great Barrier Reef went during the last ice age, says Jody Webster, a marine geologist at The University of Sydney in Australia and the lead author of the study. “We were able to find it.”
But the reef couldn’t always keep up with changing sea levels. The researchers identified five times when it appeared to die off—twice during the cool down of the last ice age, when falling sea levels exposed corals to air; and three times 10,000 to 17,000 years ago, when glacial melt caused sea levels to rise rapidly. “We haven’t drilled or sampled everything,” says Webster, so he and his colleagues can’t confirm how extensive the die-off was. But they think corals persisted in some places along the continental shelf during those times, allowing reefs in other locations to re-establish within 2000 years.
The historical die-offs are similar to “what we’re seeing right now on the Great Barrier Reef,” says Mark Eakin, a coral reef ecologist at the National Oceanic and Atmospheric Administration in College Park, Maryland, who wasn’t involved in the study.
The new research is “yet another reminder” that what we’re doing to the ocean is going to have dramatic consequences, Eakin says. “Don’t expect reefs to be able to bounce back quickly.”
My first thought was, “No schist Sherlock.” The Eemian coral reefs of Florida are currently located in onshore quarries. Florida’s coral reefs of the Last Glacial Maximum are dead and buried in deeper water than Florida’s current coral reefs. Coral adapts. Coral moves. Coral has a far better handle on climate change than NOAA ever will.
My second thought was, WTF?
“The new research is ‘yet another reminder’ that what we’re doing to the ocean is going to have dramatic consequences, Eakin says. ‘Don’t expect reefs to be able to bounce back quickly.'”
The only logical takeaway from this study (and reality) is that coral adapts, coral moves, coral has a far better handle on climate change than NOAA ever will. How in the hell could anyone interpret this as indicating that coral is more fragile than previously thought? Or that somehow, coral can’t adapt to the “Anthropocene”… When it readily adapted to far more dramatic climatic changes over the past
30,000 200 million years?
A few years ago, the coral reef experts at the World Bank proclaimed that coral could not survive at CO2 levels above 550 ppm.
3. Coral reefs are doomed
Coral reefs, which protect against coastal flooding, storm surges, wave damage, and also provide homes for lots of fish, are doomed on our current course, says the World Bank. Coral reefs are dissolving because of ocean acidification–the more CO2 in the atmosphere, the more gets dissolved in the oceans. The illustration shows the impact on coral reefs at various CO2 levels. Coral reefs may stop growing as CO2 concentration levels approach 450 ppm, which is expected over the coming decades. By the time the concentration reaches around 550 ppm in the 2060s, coral reefs will start to dissolve.
Scientists, presumably with straight faces, claimed that greater than 550 ppm CO2 was doomsday for coral reefs. No wonder the Great Barrier Reef keeps coming back from the dead. It boggles the mind.
I forgot to ridicule this bit of nonsense:
Today’s rate of sea level rise is moderate—about 10% of the rate 13,000 years ago—but going forward it may accelerate dramatically, she says.
100% unmitigated bullschist.
More Mind-boggling Facts About Coral Reefs
Coral reefs can handle “highly acidic ocean waters”…
Pacific Mystery: Coral Reefs Are Thriving, But How?
Jun 5, 2015
A College of Geosciences researcher and her colleagues have found healthy coral reefs in highly acidic ocean waters. “The reefs appear to be thriving, and we want to understand why,” says Kathryn Shamberger, assistant professor of oceanography.
The team examined eight coral reefs in the Palauan archipelago and found high levels of acidification within the lagoons and inlets of the Palau Rock Islands. But despite the high levels, the Rock Island coral reefs appear to be extremely healthy.
“Based on lab experiments and other studies, this is the opposite of what we expected,” says Barkley, the lead author.
The team says that the acidification process in Palau is a natural one, due to a combination of biological activity and the slow flushing of water through the Rock Island lagoons that allows acidification levels to build up over time.
Sediment laden waters…
Coral reef thriving in sediment-laden waters
Rapid rates of coral reef growth have been identified in sediment-laden marine environments, conditions previously believed to be detrimental to reef growth.
A new study has established that Middle Reef – part of Australia’s iconic Great Barrier Reef – has grown more rapidly than many other reefs in areas with lower levels of sediment stress.
Rising seas (AKA deeper water)…
Great Barrier Reef found to have thriving deep water coral
Updated 2:23 AM ET, Fri October 26, 2012
A recent survey of the Coral Sea and Great Barrier Reef has found coral flourishing in deep waters, a stark contrast to the shallower reefs that have seen a drastic decline over the last few decades.
The healthy coral populations were discovered to be below 30 meters — beyond the usual reach of most scuba divers — and even found at depths of 80 meters, according to the Catlin Seaview Survey.
Rottnest’s tropical corals found to thrive
July 9, 2015 by Kerry Faulkner
Researchers are surprised at thriving coral growth at Rottnest Island, predicting its smaller coral communities could grow into a reef similar to the one that existed there in the Last Interglacial, approximately 130,000 years ago.
Hong Kong coral reef thrives despite pollution
Amid major developments, territory’s scientists make unexpectedly pleasant underwater discovery.
08 Oct 2015
Marine life is thriving despite major developments at Hong Kong’s busy harbour.
Like any other marine environment around the world, this region is feeling the impacts of climate change and development.
Nevertheless, the stronger types of coral species are holding on despite the unrelenting conditions and scientists are now trying to establish how they survive.
Scientific Assessment Of Curaçao’s Coastal Waters Show Healthy And Thriving Coral And Fish Populations
WILLEMSTAD – A recent two-week long scientific assessment surveyed over 150 dive sites of Curaçao’s shallow water reef sites and found signs of healthy coral and fish populations around the island, particularly in Oostpunt. The scientific assessment was a critical step in Blue Halo Curaçao and its comprehensive, science-based approach to ocean zoning.
A lack of data…
For marine biologists, the destruction of the reefs has proven to be as frustrating as it is heartbreaking. Because reef habitats are so complex, and because worldwide reef monitoring and mapping efforts only began a little over a decade ago, scientists simply do not have enough information to keep tabs on the destruction of the reefs, let alone come up with an effective solution. At the rate the reefs are disappearing, they may be beyond repair by the time a comprehensive plan to save reefs can be put into place…
Harsh intertidal zones…
A Diverse Assemblage of Reef Corals Thriving in a Dynamic Intertidal Reef Setting (Bonaparte Archipelago, Kimberley, Australia)
The susceptibility of reef-building corals to climatic anomalies is well documented and a cause of great concern for the future of coral reefs. Reef corals are normally considered to tolerate only a narrow range of climatic conditions with only a small number of species considered heat-tolerant. Occasionally however, corals can be seen thriving in unusually harsh reef settings and these are cause for some optimism about the future of coral reefs. Here we document for the first time a diverse assemblage of 225 species of hard corals occurring in the intertidal zone of the Bonaparte Archipelago, north western Australia.
Bad news about other ocean habitats…
Crown Jewel of Cuba’s Coral Reefs
Jardines de la Reina, a vibrant marine preserve, is thriving even as other ocean habitats decline.
By ERICA GOODE
JULY 13, 2015
JARDINES DE LA REINA, Cuba —
The sharks are a tourist attraction — at two of the many diving spots in the Gardens, they are fed to ensure larger numbers — but to scientists like Dr. Pina and Dr. Kritzer, their very presence here is an indicator of the coral reef’s robustness.
Research has linked the health of reefs to habitation by large fish, and the absence of sharks and other top predators is often a sign of a reef in decline.
The resilience of this coral reef seems beyond question. The waters inside the preserve hold 10 times as many sharks as outside, Dr. Pina said, and goliath grouper, rare in many places, are often seen here.
Glass sponge reefs thought to be extinct are discovered to be thriving in ocean depths
Mummies, they’re called, these strange shapes that form one of the largest structures ever to exist on Earth. Stretching some 2900 kilometers from Spain to Romania, the long, sinuous curve of millions of mummies—once-living, vase-shaped animals—is a fossil reef. In its heyday in the Jurassic, the reef dwarfed today’s Great Barrier Reef off Australia’s northeastern coast. Now it is visible only in rock outcrops dotted across a vast area of central and southern Spain, southwestern Germany, central Poland, southeastern France, Switzerland, and eastern Romania near the Black Sea. The ancient reef was made up not of corals but of deep-sea sponges called hexactinellids.
Hexactinellids, or glass sponges, use silica dissolved in seawater to manufacture a skeleton of four- or six-pointed siliceous spicules. Individual glass sponges, such as the beautiful Venus’s flower-basket sponge (Euplectella aspergillum), are still found in the deep sea but are a different genus and species from the Jurassic reef-builders. Reef-building glass sponges, known only from fossilized remains, are thought to have gone extinct 100 million years ago, driven out by competition from newly arrived diatoms.
The surprise find
The darkness beneath British Columbia’s Strait of Georgia, Hecate Strait, and Queen Charlotte Sound concealed the next chapter in an eons-old tale. For decades, hints of something alive—something no one had seen before—washed up on the shores of Galiano Island in the Strait of Georgia. Walking along a beach on the island, long-time resident Elizabeth McClelland found pieces of an unidentified object in the tide line. “Every so often, I’d come across bits of flotsam that were very delicate but very sharp,” says McClelland. “My granddaughter once found a fairly large piece of these unknown gifts from the sea.”
Then came an odd clue at the bottom of Hecate Strait. During a 1984 seafloor mapping expedition, scientists from the Geological Survey of Canada, using sonar imaging, saw mounds over huge areas of the seafloor—areas that should have been completely flat. Similar acoustic anomalies, as geological survey scientists Kim Conway and Vaughn Barrie referred to them, were observed again in 1986 during a survey of Queen Charlotte Sound.
Reef-building glass sponges gave up their secret to Conway and Vaughn in 1987: underwater photography in Hecate Strait captured the sponges on film. Far from extinct, the sponges were thriving in the depths off British Columbia.
BioScience (2008) 58 (4): 288-294. doi: 10.1641/B580403
An absence of scuba divers…
Corals in Musandam are thriving, report finds
MUSANDAM // A survey of the peninsula by an expedition of marine scientists and volunteer divers has found that its coral reefs are thriving.
For Dr Jean-Luc Solandt, an expedition member and one of the authors of the report, said when it came to the health of corals, the sites were in better condition than many locations famous for being scuba-diving haunts.
“It is an outstanding location,” said Dr Solandt, senior biodiversity policy officer at the Marine Conservation Society. “The coral health is excellent.”
The healthy Musandam reefs could well be a source of population recovery for reefs in the Arabian Gulf, where physical and man-made factors combine to create an environment that is more challenging for corals.
Many of the sites hosted very large colonies of the genus Porites. Some of the colonies, said Dr Solandt, were “the size of small houses”, indicating they could well be more than 400 years old.
This also most likely meant that no significant damaging events had occurred within this timeframe, said the report.
It seems to me that that scuba divers tend to whine more than other groups about Gorebal Warming and Ocean Neutralization killing coral reefs. I have also noticed variations of this in several articles…
[W]hen it came to the health of corals, the sites were in better condition than many locations famous for being scuba-diving haunts…
Maybe coral reefs don’t like scuba divers???
More sea level rise and deeper waters…
Deep-Water Coral Reefs Thriving Off Puerto Rico
Jan 14, 2011
SAN JUAN, Puerto Rico – As the ocean floor plunges off southwestern Puerto Rico, it reveals coral reefs dotted with bright-blue sea squirts and a multitude of other organisms whose existence has given hope to scientists who strive to save the island’s threatened ecosystems.
The organisms are an integral part of a group of reefs discovered to be thriving near an area where most shallow coral reefs and the fish that depend on them are in poor health overall.
The reefs – at a depth of up to 500 feet (152 meters) in an area 12 miles (19 kilometers) across – were recently discovered as part of a federally funded mission to conduct research on deep-water corals, according to the U.S. National Oceanic and Atmospheric Administration.
“We stumbled across this area,” Richard Appeldoorn, a professor at the University of Puerto Rico in Mayaguez who was involved in the mission, told The Associated Press on Thursday.
Divers enrolled in a one-year training course to depths of up to 100 feet (31 meters) noticed the thriving reefs and large predators lurking nearby, said Appeldoorn, who oversees the university’s fisheries, biology and coral reef studies program.
A Bright Spot for Coral Reefs
Air Date: Week of January 11, 2013
[C]orals in American Samoa are actually thriving despite the heat. At least that’s what researchers at Stanford University reported recently in the Proceedings of the National Academy of Science. Steve Palumbi is a professor of Marine Science at Stanford University and a lead author on the research. He explained how corals bleach and otherwise react to the stresses of heat.
Diversity of Corals, Algae in Warm Indian Ocean Suggests Resilience to Future Global Warming
12 February 2010
Penn State researchers and their international collaborators have discovered a diversity of corals harboring unusual species of symbiotic algae in the warm waters of the Andaman Sea in the northeastern Indian Ocean. “The existence of so many novel coral symbioses thriving in a place that is too warm for most corals gives us hope that coral reefs and the ecosystems they support may persist — at least in some places — in the face of global warming,” said the team’s leader, Penn State Assistant Professor of Biology Todd LaJeunesse.
Coral reefs can even handle numerous predictions of their imminent demise…
December 19, 2013
Coral reefs, the great survivors
By Viv Forbes
For at least fifty years, agitated academics have been predicting the end of Australia’s Great Barrier Reef. Now international “experts” are also sprouting coral calamity. But despite the alarms, the reef is still there.
Corals are among the greatest survivors on Earth and have been here for about 500 million years. Many of the types of corals found on reefs today were present in similar forms on reefs 50 million years ago.
Since corals first appeared there have been five mass extinctions when over 50% of all life forms on land and in the seas died.
Corals also survived several deadly ice ages when sea levels fell so low that many coral reefs left their skeletons stranded as limestone hills on dry land. But always some colonisers followed the retreating seas and survived.
Then came the hot climate eras when the great ice sheets melted and sea levels rose dramatically. Some coral reefs drowned, but others just built on top of the old drowned corals forming the beautiful coral atolls we see today. Corals flourish in gently rising seas such as we have today – it gives them room to refresh and grow vertically.
And if the water gets too warm, coral larvae just drift into cooler waters closer to the poles. The Great Barrier Reef would move slowly south.
Corals have outlasted the dinosaurs, the mammoths and the sabre-toothed tiger. Captain Cook’s ship was almost disembowelled by the sturdy corals of the Great Barrier Reef in 1770. If Cook came back today, he would be unable to detect any changes in the Reef.
No matter what the future holds, corals are more likely than humans to survive the next major extinction.
In the event of yet another Ice Age we must hope that reef alarmists have not denied us the things we will need to survive – food, energy, chemicals, shelter, concrete and steel generated by carbon fuels.
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Coral flourishing at Bikini Atoll atomic test site
Tue Apr 15, 2008
By Rob Taylor
CANBERRA (Reuters) – Coral is again flourishing in the crater left by the largest nuclear weapon ever detonated by the United States, 54 years after the blast on Bikini Atoll, marine scientists said on Tuesday.
A team of research divers visited Bravo crater, ground zero for the test of a thermonuclear weapon in the remote Marshall Islands on March 1, 1954, and found large numbers of fish and coral growing, although some species appeared locally extinct. “I didn’t know what to expect, some kind of moonscape perhaps. But it was incredible,” Zoe Richards, from Australia’s James Cook University, told Reuters about the team’s trip to the atoll in the south Pacific.
“We saw communities not too far from any coral reef, with plenty of fish, corals and action going on, some really striking individual colonies,” she said.
Chicken Little of the Sea doesn’t even bother them…
March 2013, Volume 32, Issue 1, pp 305-314
First online: 22 November 2012
Ocean acidification does not affect the physiology of the tropical coral Acropora digitifera during a 5-week experiment
A. Takahashi, H. Kurihara
The increase in atmospheric CO2 concentration, which has resulted from the burning of fossil fuels, is being absorbed by the oceans and is causing ocean acidification. Ocean acidification involves the decrease of both the pH and the calcium carbonate saturation state. Ocean acidification is predicted to impact the physiology of marine organisms and reduce the calcification rates of corals. In the present study, we measured the rates of calcification, respiration, photosynthesis, and zooxanthellae density of the tropical coral Acropora digitifera under near-natural summertime temperature and sunlight for a 5-week period. We found that these key physiological parameters were not affected…
Additionally, there was no significant correlation between calcification rate and seawater aragonite saturation (Ωarag). These results suggest that the impacts of ocean acidification on corals physiology may be more complex than have been previously proposed.
Offshore oil & gas drilling…
Spectacular reef awaits divers off coast of Galveston
KHOU Staff, KHOU.com
Jun 11, 2014
GALVESTON, Texas — When you think about Galveston, you probably picture sun and surf, maybe the Pleasure Pier or sometimes seaweed, but you probably don t think about great diving.
The sanctuary actually encompasses three separate areas, underwater salt domes that stand higher than the surrounding ocean floor. Snapper and grouper fishermen who saw the colorful sponges and other marine life under their boats are credited with discovering the ecological wonder in the late 19th century. The area was designated as a national marine sanctuary in 1992 and it s now managed under the direction of the National Oceanic and Atmospheric Administration.
At a time when coral reefs around the world are in decline, Flower Garden Banks is thriving largely because it s so remote it attracts comparatively few divers.
I’m really beginning to think that the only thing coral reefs can’t handle are too many scuba divers.
Coral reefs are amazingly undaunted by “a trend of widespread decline in coral reefs across the Caribbean”…
Scientists explore secret of Little Cayman’s coral reef success
30 December, 2014
By: James Whittaker | firstname.lastname@example.org
What is so special about Little Cayman’s reefs? That’s the question a new $140,000 scientific study at the Central Caribbean Marine Institute will seek to answer.
Scientists want to determine why reefs around the remote island are thriving and whether there are lessons that can be adapted to help protect and maintain vital coral reef systems around the world.
The new study will look specifically at rare and endangered coral species around Little Cayman and attempt to determine why they are bucking a trend of widespread decline in coral reefs across the Caribbean.
An earlier study by CCMI showed that coral cover had been increasing around Little Cayman over the past five years.
What is so special about Little Cayman’s reefs?
Here’s a SWAG… They are REMOTE.
Coral reefs even handled the much warmer Eemian (Sangamonian) interglacial stage…
Sangamon Interglacial: Paleoclimatology
and Future Climate Implications
Recent ‘extreme’ weather events, rising carbon dioxide levels and the growing evidence of retreating glaciers have increasingly become the subjects of much debate in the popular press and numerous fields of scientific research. Driving these discussions are questions aimed at discerning what drives the climate on Earth. Several have been noted in previous research: Milankovitch cycles, solar output, continental configurations and the most recent and controversial, carbon dioxide and other greenhouse gas atmospheric concentrations (Hambrey 2004). In order to understand what we should expect, both from a climate change perspective and from a changing biogeographical perspective during our current interglacial phase, scientists have looked to the last interglacial period in the geologic record, the Sangamon Stage (or the Eemian, as it appears in European literature) approximately 114,000 – 130,000 years ago for answers.
Similarly, the limestones deposited in coral reef complexes near Bermuda, the Florida Keys and part of the Miami Limestone had to have been formed in seas that are anywhere from 6 to 19 meters higher than current sea level with most sea level estimates being placed at 6 – 10 meters higher than today. These values represent data gathered during 2 of the lower sea stands during the Sangamon with the 3rd being much higher than the others based on ?O18 minimums obtained from oxygen isotope data of deep sea cores (USGS).
The implications of such a high sea level suggests that massive changes in a number of the elements that factor into establishing a particular global climate regime had to have occurred. Looking at Milankovitch cycles, the Northern Hemisphere, during the Sangamon, would have received higher insolation rates (solar radiation received on a surface during a unit of time) than today and a large portion of Greenland’s Ice Sheet and significant portions of the West Antarctic Ice sheet would have had to melt to produce the sea level rise necessary for coral reef derived limestone formations to have been generated at the elevations that they are present at today (Koerner).
Carbon dioxide concentrations weren’t as high in the Sangamon as they are today, but they were still much higher than any of the previous or following glacial periods. This combination of high CO2 and increased insolation due to Milankovitch cycle parameters would have altered the climate regimes around the globe. Global temperatures were thought to be 5-7 °C (9-13 °F) higher than the current interglacial period according to North Atlantic oceanic sediment cores with South Pacific oceanic cores showing a rise of only 3-5 °C (5.4-9 °F).
Across the majority of Europe, general scientific consensus was that the Eemian climate was much warmer and wetter than today’s environment. This resulted in the development of vast temperate forests and the rapid expansion of species, most notably Carpinus across the area (Turner 2000). Although the Eemian was consistently much warmer, evidence has been building that a large scale late Eemian arid ‘pulse’ dominated central Europe resulting in the widespread takeover of ecological niches by various grasses and shrubby bushes before returning to a warm, somewhat more moist climate dominated by temperate forests just before the most recent glacial stadial (Sirocko, et al. 2005).
Coupled with the climatic discrepancies are the discrepancies with analyzing how life will respond to the changing environment. As Smith and Buddemeier explained, looking at oceanic chemistry and a number of other factors, a rise in sea level could actually benefit most coral reef complexes if sea level and atmospheric carbon dioxide concentrations rise at anticipated rates within the next 100 years. The net effect would cause a drawdown of atmospheric carbon dioxide as more of this greenhouse gas gets incorporated as CaCO3 as various reef complexes grow. Overall, Smith and Buddemeier make a valid point when they explain that the number of factors affecting coral reef health and viability, coupled with the modest changes expected from various climate change simulations indicate that on a global scale, coral reefs are unlikely to be adversely affected by projected climate change. It is only on the local scale that coral reef communities could be at risk.
Fortunately for coral reefs, there were no scuba divers 130,000 years ago.
More deep water and even more surprised scientists…
Science Features – Discoveries of the Deep—The Surprising Undersea World at Pulley Ridge
In the deep waters of the Gulf of Mexico, approximately 250 km west of Cape Sable, Florida, and 70 km west of the Dry Tortugas, are a series of drowned barrier islands known as Pulley Ridge. The ridge was found in 1950, but it wasn’t until recent years that scientists discovered something extraordinary.
The southern portion of the ridge is a thriving coral reef, a pristine habitat teeming with life and color. Here, more than 60 species of fish swim in predominantly clear, warm water. An abundance of algae sprinkles the seascape in vibrant reds and greens. Brilliant blue-purple corals stretch across the sea floor like giant plates. Octocorals, with tiny featherlike tendrils and colors that vary per colony, reach out with sometimes light and delicate and sometimes bright and knobby arms. And in the soft light that filters down from the distant surface, luxuriant fields of the leafy algae Anadyomene menziesii rise from the sea floor like patches of lettuce at dusk.
The reef was discovered in 1999, as scientists and graduate students from the USGS Center for Coastal & Watershed Studies and the University of South Florida (USF) boarded the research vessel Bellows and set sail for the Pulley ridge area, where a bathymetric map of the ocean floor showed a mysterious bump.
Why does it always shock the “scientists” when they discover healthy, thriving coral reefs?
It seems as if every newly discovered reef is healthy and thriving… particularly if it is in a remote area and not frequented by scuba divers?
How are these remote reefs miraculously immune to Gorebal Warming and Ocean Neutralization?
Coral reefs can even handle being denigrated as endangered species…
Hybrid Corals: Sex Gone Awry or Saving Grace?
As the full moons of late summer and fall rise, so too, does the libido of threatened staghorn (Acropora cervicornis) and elkhorn (Acropora palmata) corals.
By Marah J. Hardt on September 25, 2014
As the full moons of late summer and fall rise, so too, does the libido of threatened staghorn (Acropora cervicornis) and elkhorn (Acropora palmata) corals. Awakened from a year of sexual slumber, each species shakes off the shackles of celibacy to engage in a mass-spawning a few days after the brightest nights. Facing declines of up to 97 percent in the past 30 years, these two species have been beaten back by disease, pollution, overfishing and climate change. Their yearly spawning should be a time of celebration. But after millions of years of successful group sex, the very act of reproduction may now be contributing to their ultimate demise.
A report this summer adds to a growing body of evidence that another coral, Acropora prolifera, may be overtaking reef real estate formerly occupied by elkhorns and staghorns. Far from a foreign invader, genetic tests show this coral is in fact the offspring of an elkhorn and staghorn cross. A. prolifera is a hybrid. And its apparent rise is an indication of coral sex gone awry.
If Acropora cervicornis and Acropora palmata can interbreed to produce genetically viable offspring (Acropora prolifera), they are not distinct species and should not be listed as endangered species. Acropora is not endangered, prolifera should be a big, fat clue.
Coral reefs appear to be adapting quite well to climate change and Chicken Little of the Sea, if not adapting so well to scuba divers, snorkelers, agricultural runoff and fishing with dynamite.
Coral reefs really do seem to like warm water and lots of CO2 in their diets…
GBR calcification rates from:
De’ath, G., J.M. Lough, and K.E. Fabricius. 2009.
Science, Vol. 323, pp. 116 – 119, 2 January 2009.
(Previously discussed here.)
According to Byrn et al., 2010, “Global ocean acidification is a prominent, inexorable change associated with rising levels of atmospheric CO2…”
The boron 10/11 ratio from Flinders Reef (GBR) demonstrates that seawater pH around the reef has generally ignored atmospheric CO2 over the past 250 years and that the coral has easily adapted to 0.2 pH unit swings every 50-60 years…
Declining pH has been “associated with rising levels of atmospheric CO2” since about 1990. Prior to 1990, rising and falling pH levels weren’t associated with rising or falling levels of CO2. (Station Aloha discussed here.)
However, the rising and falling pH appears to be inversely correlated with the Pacific Decadal Oscillation (PDO)…
That’s really funny… Because the PDO supposedly can’t drive anything. It’s just an index of North Pacific sea surface temperatures and Flinders Reef is in the Coral Sea. The PDO and Flinders Reef are on opposite sides of the equator.
Average annual pH reconstructions and measurements from various Pacific Ocean locations:
- 60 million to 40 million years ago: 7.42 to 8.04 (Pearson et al., 2000)
- 23 million to 85,000 years ago: 8.04 to 8.31 (Pearson et al., 2000)
- 6,000 years ago to present: 7.91 to 8.28 (Liu et al., 2009)
- 1708 AD to 1988 AD: 7.91 to 8.17 (Pelejero et al., 2005)
- 2000 AD to 2007 AD: 8.10 to 8.40 (Wootton et al., 2008)
The low pH levels from 60 mya to 40 mya include the infamous Paleocene-Eocene Thermal Maximum (PETM). Even then, the oceans did not actually “acidify;” the lowest pH was 7.42 (still alkaline).
The Eniwetok/Bikini coral reef complex dates back to the Eocene. Oddly enough, there is an unconformity between the Eocene and Miocene. There was apparently little or no coral growth during the Oligocene, a period of global cooling and falling sea level.
Reef waters are bad places to measure pH – way too much photosynthesis going on. However, reefs are the only decent source for continuous, high resolution reconstructions of paleo-pH.
Open ocean pH time series, like HOTS, show very little pH variation compared to Flinders Reef and of are far too short a record length to identify any of the natural cyclical variability documented in Flinders Reef.
There are no measurements of pre-industrial oceanic pH, apart from boron isotope proxies from ancient coral reefs and these show no secular pH trend.