Measuring Old Corals & Coral Reefs (Part 1)

Reposting from Jennifer Marohasy’s Blog

November 27, 2020 By jennifer

Fundamental to science is measurement. It is a way of objectively assessing something, anything, even the state of a coral reef, even of an individual coral. Historically coral growth rates were measured by coring the really old massive Porites.

Like tree rings in temperate forests, the massive old Porites can be cored to see the banding and from this it is possible to calculate coral calcification rates which are a measure of the growth rate of individual corals.

Peter Ridd has been asking for some quality assurance of so many of the measurements relating to Great Barrier Reef health, including coral growth rates. Key Australian institutions have responded by stonewalling, and in the case of James Cook University, actually sacking him. After two rounds in the federal courts his appeal against his dismissal is finally going to the High Court of Australia, with the next hearing probably in February 2021. While the lawyers are preoccupied with Peter’s rights, or otherwise, to academic freedom and freedom of speech, my concern is whether Peter is actually telling the truth when he says that the Great Barrier Reef is resilient and definitely not dying from coral bleaching, though there is a problem with the integrity of the science.

Most media reports, based on extensive aerial surveys by his one-time colleague Terry Hughes, conclude that the reef is variously 50% or 60% dead from coral bleaching as a direct consequence of global warming.

These media reports do not consider coral growth rates, but rather the area of coral that Professor Hughes has measured to be bleached, with an inference being that this will all die.

Terry Hughes and Peter Ridd can’t both be right.

How can they have come to such different conclusions regarding the health of the Great Barrier Reef? Is the reef really half dead, or not?

Jen/me the other side of a red Gorgonian coral, just two days ago at Pixie Reef.

My working hypothesis is that Terry Hughes’ claims the reef is half dead, are not objective because there is a flaw with his particular survey method. This method is detailed in the technical literature, specifically his paper in Ecology published in 2018 entitled ‘Large-scale bleaching of corals on the Great Barrier Reef’.

Science is not a truth. It is a way of getting to the truth via some method or other that often involves measurement. Sometimes scientists get the method wrong, and so they come up with answers that are also wrong. Sometimes the wrong answer pleases because it is politically correct.

Could it be that in surveying by looking out the window of an aeroplane at such a high altitude (150 metres), and then ground truthing only with respect to a particular reef habitat-type known as the ‘reef crescent’, Professor Hughes has inadvertently recorded a wrong answer? Could he be avoiding, even in denial, when it comes to all the corals in the reef lagoon?

Marine scientists, and anyone with experience diving coral reefs, knows that there are distinct ecological zones at coral reefs. The reef crest, as the name suggests, is the highest part with corals in this habitat often exposed at low tides, sometimes rained-on, and during storms and cyclones this is the part of the reef that will be most likely smashed by big waves. Not surprisingly this habitat/area of a coral reef may be totally devoid of live coral or the coral may be more stunted, and sparse. At the same reef there may be healthy corals in the lagoon and back reef to the leeward side of the crest, and also corals growing down the front slope, even around the perimeter of the crest if it is a flat-topped platform. So, in only surveying the crest, the scientist/Terry Hughes could come away with the impression the reef is dead, when it is actually teeming with life – just not at the reef crest.

Pixie reef from about 100 metres altitude (thanks to my drone Skido). In the foreground (with our boat) is what is known as the reef lagoon. Then there is the reef crest which is mostly showing as beige in colour. Beyond the crest is the front of the reef that slopes more steeply to a greater depth. The types of coral vary so much with these three different habitat types.
A lower altitude picture more clearly showing a delineation between the reef lagoon and reef crest, at the one reef, Pixie Reef not far from the city of Cairns in Far North Queensland.

Professor Hughes specifically states in his 2018 article that underwater surveys were conducted to assess the accuracy of aerial surveys using five 10 x 1m belt transects placed on the reef crest. There is no suggestion that he distinguished between the different reef habitats. He only surveys the reef crest. He surveyed the area that probably had the ‘worst’ and ‘least’ coral.

I tested my hypothesis that Professor Hughes’s methodology is flawed at Pixie Reef just two days ago (25th November). We put my drone Skido into the air and took photographs at 5, 10, 20, 40, 100 and 120 metres of altitude at the reef crest, reef lagoon and reef front slope. Following are photographs just at 5 and 120 metres and just from the crest and lagoon at Pixie Reef. (If I can get a large collection of these type of photographs together from different reefs, they could form the basis of a note for publication about measurement and the importance of measuring different habitat types at the same reef if the idea is to understand the health of the entire reef ecosystem, not just the reef crest.)

A photograph taken at 120 metres altitude of the reef crest is quite different from a photograph of the reef lagoon taken at exactly the same altitude. At 120 metres altitude parts of the reef crest looks rather barren, perhaps bleached. Hughes has mostly concluded that the Great Barrier Reef is 60% bleached from 150 metres looking out a plane window at the reef crest.

The reef crest at Pixie Reef looking down from 120 metres.
The reef lagoon at Pixie Reef looking down from 120 metres. Photograph taken on 25th November with Skido.

The rather large circular boulders in the lagoon photograph from 120 metres up are massive Porites corals. The type of coral that Peter Ridd would like AIMS to core, so we had an objective measure of coral growth rates back 100s of years.

Jen/me laying a tape measure to know that this Porites is about 1.2 metres in height and 1.8 metres wide. These are external measurements. I wonder how old this coral is? It would be possible to know its age through coring (an internal measure), and then by counting the annual growth rings.
This is a close-up of the same Porites showing its golden-coloured tentacles. When the tentacles are retracted, I wonder if the coral is pale pink in colour, rather than golden?

The photograph of the reef crest from 120 metres altitude was taken with the drone (Skido of course) lifted vertically from 5 metres to 120 metres. This is what the same reef looked like at just 5 metres above the crest. There are live corals but no massive Porites or even red Gorgonians, though both exist at Pixie reef but would have been excluded from a 10 metre belt transect across the reef crest and from an aerial survey of the crest, because they exist in a different habitat type.

The reef crest at just 5 metre’s altitude.

A photograph taken at 5 metres from above a section of reef lagoon shows plate corals, presenting as toadstools when photographed from under-the-water, which seems most appropriate given this is Pixie reef. I didn’t find any pixies though.

The reef lagoon at just 5 metres altitude. To really know the corals it is necessary to go under the water, of course.
This is what a plate coral looks like under the water. Of course, at Pixie reef it may look more like a toadstool.

So much thanks to Stuart Ireland for taking me to Pixie Reef, and for taking all the photographs under-the-water, and he also flew Skido. All the photographs (except the shutterstock of the coring), were taken at Pixie reef on 25th November 2020. Pixie reef is just to the north east of Cairns in Far North Queensland.

****
The image at the very top of this blog post is of me/Jen swimming over the top of a 7 metre wide Porites at Pixie Reef on 25th November 2020. This is the type and size of coral that Peter Ridd would like to think was still being cored by the Australian Institute of Marine Science (AIMS), as an objective measure of coral growth rates. AIMS used to core these old corals, to get an idea of climate change back hundreds of years. This coral could be more than 400 years old, with annual bands that can be measured at the scale of one year, year on year perhaps back 300 or 400 years to calculate an annual growth rate. So, from the one coral we could (if they cored it) see if growth rates have increased or decreased year on year, or not.ShareTweetShare

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Coeur de Lion
November 29, 2020 2:22 pm

Marvellous. But how come the corals are there to die if global warming does it? Surely the MWP would have killed them ? Oh sorry Mikey Mann did away with it.

Greyleader2
Reply to  Coeur de Lion
November 30, 2020 3:20 am

There is no hope.
They are all going to die.
And the reason?
Carbon dioxide and acidification of the oceans. (?)
How do we know this?
David Attemnborough says so !!!!!!!!!!!!!!!!!!!!
https://www.independent.co.uk/arts-entertainment/tv/david-attenborough-coral-reefs-dead-2100-blue-planet-2-a8103416.html
The problem is that most people actually believe this

Mr.
November 29, 2020 2:27 pm

Thank you once again Jennifer for outing the perfidy of Hughes et al.

For years now they have made up “status reports” on the GBR, banking on the fact that the main reef body is remote and inaccessible for ordinary folk who might take an interest in seeing for themselves what the reefs really look like up close.

Keep up your essential work Jennifer & team.

MarkW
November 29, 2020 2:44 pm

My biggest problem with Hughes et. al. is that how could anyone who knows anything about reefs, make the claim that bleaching is equivalent to dying?

Mr.
Reply to  MarkW
November 29, 2020 3:42 pm

Maybe like Tim Flannery he used to study old kangaroo bones?

They’re white and dead, so there’s your correlation right there.

Loydo
Reply to  MarkW
November 30, 2020 3:18 am

Where did Hughes et. al. say that? Or are just you making it up? Come on big boy show us the exact quote.

YallaYPoora Kid
Reply to  Loydo
November 30, 2020 5:00 am

Read or research and find out yourself

Jeff Alberts
Reply to  YallaYPoora Kid
November 30, 2020 9:54 am

No, the person making the claim should provide the evidence.

Redge
Reply to  Redge
November 30, 2020 11:29 am

I’m going to correct myself here because he doesn’t use the term “dying”

fred250
Reply to  Loydo
November 30, 2020 11:16 am

Poor little-child, Loy-dumb. Start paying more attention to what your priests say…

…. or you will cast out from the cult of CO2 haters.

https://www.coralcoe.org.au/tag/terry-hughes

““Dead corals don’t make babies,” said lead author Professor Terry Hughes”

Probably the most ignorant and anti-science quote EVAH !!!

Or this one

https://twitter.com/ProfTerryHughes/status/866155996078522368?t=1&cn=ZmxleGlibGVfcmVjc18y&refsrc=email&iid=2c703084271048f6931809a306e3df86&uid=1096834050&nid=244+27269939

Mr.
Reply to  fred250
November 30, 2020 12:14 pm

Don’t look at this Hughes tweet that fred250 put up Loydo.
You don’t want to have to believe your lyin’ eyes.

fred250
Reply to  Mr.
November 30, 2020 2:26 pm

Nah, being proven WRONG in everything he/she/it says,…

….. is like water of a duck’s back to loy-dumb.

BEING WRONG is what he/she/it thrives on. !

Its life is based around being wrong… always.

Loydo
Reply to  Mr.
November 30, 2020 8:55 pm

Here is the tweet:
30% of #corals died following bleaching in 2016, another 19% this year

That doesn’t say ” bleaching is equivalent to dying”.

Make-it-up Mark just made it up and you two blinkered twits have credulously doubled down on it, smh. Mmmm, rigorous standards – about par for the course in a piece about the GBR on WUWT.

fred250
Reply to  Mr.
November 30, 2020 10:18 pm

Twist, slither and squirm, little Loy.

DENIAL of what is directly in front of you.

So SAD (and funny) that you have to stoop to LYING even to yourself.

But what else do you have!! you poor mindless little twerp.

fred250
Reply to  Mr.
November 30, 2020 10:27 pm

Off you trot, Loy-dumb

Go and tell your priest Terry, that bleaching doesn’t cause coral to die.

So glad you are on OUR side… 😉

Try not to be a complete LOSER as you tell him.

Eric Stevens
November 29, 2020 2:59 pm

There is a limit as to how high coral reef can grow. Once it gets to the surface it will be regularly be exposed by the tides and its growth will suffer. The surface will bleach from exposure and what living corals there are will be seen to be struggling to survive. It is astonishing that the reef’s general state of health should be judged by the condition of corals which have reached their uppermost growth boundary. This doesn’t even rate as sensible, let alone good science.

Latitude
Reply to  Eric Stevens
November 29, 2020 5:50 pm

but unfortunately…it’s also their favorite place to grow

Reply to  Eric Stevens
November 30, 2020 3:53 am

Sort of like measuring the health of my body by looking at my needing-to-be-cut toenails.

Latitude
Reply to  ResourceGuy
November 29, 2020 5:53 pm

…and now they are basking in the tubs in Marathon….Florida Keys

thingadonta
November 29, 2020 4:51 pm

Their death is always around an ever receding corner.

In the land of fantasy science, things can be ever accelerating, ever receding, and ever getting worse, all of which is unprecedented.

Robert of Texas
November 29, 2020 5:27 pm

I should thin someone by now would have installed a simple skeleton for a “fake reef” to grow on. Say the skeleton reef made of some sort of material that corals will grow on weighs 200 pounds initially. It would be a simple matter to weigh the fake reef every year thus measuring growth rates in pounds instead of mm.

Using several fake reefs one could then measure different zones, depths, etc. One could compare different reefs, including ones close to rivers where agriculture runoff might be damaging corals.

Estimating coral damage or growth by looking outside an airplane window is about as scientific as estimating polar bear populations by flying across a narrow strip of ice. You can make up whatever you want.

Thomas Englert
Reply to  Robert of Texas
November 29, 2020 11:18 pm

I think you would have to remove the reef from the water to weigh it.

Gary Pearse
Reply to  Thomas Englert
November 30, 2020 4:58 pm

Measure its volume. CaCO3 has an SG of 2.7 tonnes per cubic metre. Probably go with ~2.4. You could take a few samples and measure their SG.

Gary Pearse
November 29, 2020 5:39 pm

Perhaps a Go Fund Me is in order to provide serious competition to AIMS. It doesn’t seem to be a complicated study and the world over is interesred in the GBR. Seems a certainty that there would be funds forthcoming. This is an extremely important matter is it not?

I’ve suggested a similar fund to count and measure the health of polar bears for the exact same type of problem. The Polar Bear Group have been cheering on the decline of polar bear numbers and health for over a quarter century (just like the last coring campaign on the GBR). They were so sure their models re declining Arctic ice and bear viability are correct that they did a large survey in 2012 (the record low summer ice year) . They never reported the findings of this survey!! Anecdotal evidence, Inuit hunter and villager reports and recent photos of fat bears with twins and triplets would suggest a very nefarious reason for not reporting on the survey. There probably is a mechanism for demanding funds be returned for lack of performance of work and for future funds to be strictly controlled.

Anthony Watts with his surface stations thermometer survey shook the “climate wroughters” to the core. I’m certain that his work singlehandedly (of course he had scores of vounteers, though) pre-empted a couple of degrees being added to the warming once the skullduggers were on notice.

Since this whole Climate enterprise has already revealed itself as a Eurocentric global governance scheme to collapse Western civilization and its economies, I think a competitive effort to out these and all other charlytans before this possibility is goreclosed on and the tricksters have all taken handsome pensions.

Forrest Gardener
November 29, 2020 5:44 pm

My memory must be failing me. I could swear that a couple of years back almost all of the reef was pronounced dead. Not dying but dead.

So is the official story now that it was dead but got better?

Pat from kerbob
Reply to  Forrest Gardener
November 29, 2020 6:33 pm

Parrots and reefs
Normal habits apparently

Some of those corals looked blue to me…..

Malcolm Chapman
Reply to  Pat from kerbob
November 30, 2020 3:24 am

Some of the Norwegian corals are struggling, apparently, having found many ways to be dead.

Joel O'Bryan
November 29, 2020 5:48 pm

Technology marches on.
The use of inexpensive UAVS (relative to manned-aircraft and time on them) with 20+ megapixel high resolution zoom photography and 4k HD video are revolutionizing this field of study to enable first class science on a shoestring budget. Large areas can be imaged in wide-field images. Close inspection and then underwater imagery can be used to validate coloring of various corals to show they are alive and robust with life.
Ultimately these minimalist budget, but high return for the dollar will evolve to low-cost AI-based imagery analysis to map out all the actual dead vs living corals areas in every area of a very large reef. This will stop the politicized pseudo-science coral studies claiming 50% are dead coral and other such bollocks. Of course that threatens the funding gravy train for those pseudo-scientists who also play as gatekeepers on the higher-ranked journals.

The solution: A well maintained, curated web site of coral imagery by specific areas that can be “clicked on and download” with tabular AI imagery results of live/dead, and species provided. The terabytes of needed storage would be cloud-based and is getting cheaper every year. But then once in the cloud on secure servers, there is no way anyone could “censor” that truth. Claims of “50% dead GBR” would be shredded by irrefutable evidence to the contrary. The academic rent-seekers are horrified by this prospect of low-budget science derailing their gravy train.

Ron Long
November 29, 2020 5:48 pm

Another great report from Jennifer. We geologists are used to seeing limestone, which is about 10% of sedimentary rock, and is around 75% of sedimentary actually exposed at the land mass surface. Limestone is the debris from a living reef, so the reef is the “limestone factory” (h/t Dr. Jon Thorsen). So reefs are transitory events, they form, they migrate slowly, they shed drbris, and sometimes they perish. All of this nonsense about bleaching/dieing/thermal degrading of reefs is not something a geologist believes in.

Mike
November 29, 2020 5:49 pm

Surely it is beyond stupid to suggest that a few bleaching events is enough to put reef systems in mortal danger given their success over hundreds of millions of years. SURELY !
If there is evidence of hazards from other sources let’s see it, but I cannot believe that corals have not dealt with warmer than normal water for extended periods before.
I’m sorry but it don’t add up. It seems the people claiming this are doing so more from a position of self survival than anything else. Reef ”saving” has become an industry – evidenced by the $800 million (?) thrown in their direction a year or so ago.

pcman999
Reply to  Mike
November 29, 2020 9:07 pm

Exactly! If the media wasn’t so brain-dead, they would ask if a tiny increase in temperature is so bad for the GBR than why are the reefs in the warmer and calmer waters of Indonesia doing so well?

Latitude
November 29, 2020 5:58 pm

“with annual bands that can be measured at the scale of one year, year on year perhaps back 300 or 400 years to calculate an annual growth rate”

Jen….coral paleoclimatology just does not work
…core from the top down…you may not get bands at all
core on the side facing the equator….you may get huge bands with a lot of space in between
core on the opposite side….and you’ll get small tight bands that run together, fuse, wavy, and blur

Pat from kerbob
November 29, 2020 6:36 pm

I went snorkeling at the very southern end of the reef in 2004, boat out of Town of 1770

The reef we stopped at looked dead to me from the boat, tide was just coming in so you could actually walk among the corals in knee deep water
Within a while it was covered and I got after the snorkeling

Didn’t sunscreen the backs of my calves that day.

A painful but valuable lesson

That and when a turtle shot out past me from under an over crop, body control important in the ocean

Mr.
November 29, 2020 6:43 pm

I find it troublesome that the msm hasn’t run hard with reports about how the corals in the Bikini Atoll lagoon, which were annihilated by atomic bomb testing just ~ 70 years ago, have completely regrown.

Without any interventions from “science”

I would have expected that by now the msm reports would have totally exhausted those appallingly over-used descriptors – “amazing!” and “awesome!”

November 29, 2020 10:15 pm

1. An interview with the leader of the group, Prof Terry Hughes.
https://www.carbonbrief.org/carbon-brief-interview-prof-terry-hughes
“The first global mass bleaching event was in 1998 and that’s when most marine biologists who were active at that time first personally experienced coral bleaching. It’s the first time the Great Barrier Reef bleached.”

2. You may recall Valerie Taylor made many TV documentaries with her husband Ron about sharks. She’s now 83, and still dives. They were Scuba pioneers – well before scientists; she is probably the most experienced observer of the GBR. She says
“1965 we went from one end of the reef to the other, over six months, and we found bleaching then. In the ‘70s we went back and you’d never know it happened. The coral had recovered; nature had taken care of it. I’ve seen reefs in PNG that were as white as snow and I’ve just come back from there and they’re terrific.”

3. Further,
A recent (peer-reviewed) article found that coral bleaching had been occurring throughout the entire period of their 400 year study.
[“Reconstructing Four Centuries of Temperature-Induced Coral Bleaching on the Great Barrier Reef Nicholas A. Kamenos and Sebastian J. Hennige”
Front. Mar. Sci., 15 August 2018 | https://doi.org/10.3389/fmars.2018.00283? ]

So much for no bleaching before 1989 claimed by Hughes! Therefore, it’s natural and nothing to do with carbon dioxide levels.

4. Additionally, from my site’s The Commentary
“As it is mainly the relatively untouched northern areas of the GBR affected, it is unlikely that run-off is the cause. The current bleaching decreases towards the south, flowing on the north-to-south counter-clockwise current from Vanuatu, along southern PNG, then south along the Queensland coast, and becoming depleted in the process. Upstream undersea volcanic activity around Vanuatu produces toxic H2S (Chapter 4a, Cyclone Pam), in time oxidising to sulphuric acid, lowering pH, but less toxic at that level. Chapter 5 shows the small acidity produced by CO2 is not a concern.
Other coral bleaching areas around the globe, eg Seychelles, Caribbean, Maldives, etc are downstream from undersea volcanic areas. However, Persian Gulf corals are not influenced by undersea volcanic areas and are not bleached, despite being 36°C – much higher than the GBR’s 32°C encountered preceding bleaching events.”

richard moore
November 30, 2020 1:56 am

The sea level rise of 100 meters in the last 20,000 years accompanying the climate change that melted glaciers means that any corals found near the surface today must be relatively young. Are there older remains of coral reefs at one hundred meters depth off the face of the GBR?

Anonymoose
November 30, 2020 6:29 am

What is a ‘reef crescent’? You mention that phrase once, then explain reef crests.

DMacKenzie
November 30, 2020 12:52 pm

Wouldn’t 1/3 of them being on their way to death and 1/3 on their way to thriving and 1/3 unknown, be a very normal and expected condition ?….Plus aren’t the near surface ones that we can readily see and visit be much more likely to suffer from storm surge, tides, and exposure to excessive sunlight as they carelessly grow above some optimum depth ? Aren’t islands and reefs themselves, boringly composed of DEAD coral ? It seems so much like a “send me money to cover my scuba diving and warm weather motor-boating hobby” kind of thing……

December 2, 2020 5:29 pm

There is a long tradition of myths of death and resurrection, the barrier reef coral myth of repeated death and return to life joins this rich collection of cultural mythology.

For example, Osiris of ancient Egypt was one of the first to be associated with the mummy wrap. When his brother, Set, cut him up into pieces after killing him, Isis, his wife, found all the pieces and wrapped his body up, enabling him to return to life.

The Sumerian deity Dumuzid has a sister Inanna who dies. Dumuzid fails to adequately mourn Inanna’s death and, when she returns from the Underworld, she allows the galla demons to drag him down to the Underworld as her replacement. Inanna later regrets this decision and decrees that Dumuzid will spend half the year in the Underworld, but the other half of the year with her, while his sister Geshtinanna stays in the Underworld in his place, thus resulting in the cycle of the seasons.

In corresponding Greek mythology the goddess Aphrodite found the infant Adonis and gave him to be raised by Persephone, the queen of the Underworld. Adonis grew into an astonishingly handsome young man, causing Aphrodite and Persephone to feud over him, with Zeus eventually decreeing that Adonis would spend one third of the year in the Underworld with Persephone, one third of the year with Aphrodite, and the final third of the year with whomever he chose. Adonis chose to spend his final third of the year with Aphrodite.

Likewise Dionysus was believed to have been born from the union of Zeus and Persephone, and to have himself represented an underworld aspect of Zeus. Many believed that he had been born twice, having been killed and reborn as the son of Zeus and the mortal Semele.

In ancient Turkey the daemon god Agdistis initially bore both male and female attributes – a non-binary god! But the trans-phobic Olympian gods, fearing Agdistis, cut off the male organ and cast it away. There grew up from it an almond-tree, and when its fruit was ripe, Nana, who was a daughter of the river-god Sangarius, picked an almond and laid it in her bosom. The almond disappeared, and she became pregnant. Nana abandoned the baby (Attis). The infant was tended by a he-goat. As Attis grew, his long-haired beauty was godlike, and his mother, Cybele, then fell in love with him. And so on …

Now to add to this we have the myth of coral trolls that lie underwater staring at the moon each night. When the world of men pollute the air with their foul engines, the trolls can no longer see the moon at night. So in grief they banish the algal cells from their mineral matrix and turn as pale as the moon, in this way entreating the skies to clear and the moon to return. The moon on due course returns but the coral trolls die. However the moon urinates into the sea fertilising new growth of the coral trolls which return to life. And so the cycle of death and rebirth of the corals continues endlessly.

R Moore
Reply to  Phil Salmon
December 3, 2020 12:53 am

Why not

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