Mangrove, Australian Eastcoast, possibly Cowie Beach. Patrick Bürgler, CC BY-SA 4.0, via Wikimedia Commons

Coral Island Expedition Discovers Tropical Mangroves Grabbing More Land

Guest essay by Eric Worrall

h/t JoNova; A field expedition to investigate remote islands on the Great Barrier Reef has discovered the islands are growing.

Magic mangroves a ‘blue carbon’ buffer for Great Barrier Reef

By Liam Phelan

January 8, 2022 — 9.00am

A scientific field trip to a small group of deserted islands on the Great Barrier Reef has its roots in a 1928 expedition and has implications for the future of the reef.

A team of researchers from the University of Wollongong led by Associate Professor Sarah Hamylton visited the Howick islands, about 130 kilometres north-east of Cooktown, in far northern Queensland, last year and found the mangroves were expanding.

“What’s particularly interesting for a lot of the islands in the Howick group that we are mapping and investigating is that they are growing,” Associate Professor Hamylton says.

“Most of the islands we have looked at are predominantly made up of broken up corals, which waves then sweep and deposit on the island. This coral sediment is responsible for building up the islands. Add in mangrove forests and you can see that these islands are actually growing. Some mangrove forests are marching forwards by up to five to six metres per year,” she explains.

Associate Professor Hamylton says the group was able to compare aerial images taken by a drone with hand-drawn maps created in 1928 and photographs from 1974.

A PhD student in philosophy Oxana Repina says the research is now more important than ever.

“The fate of the Great Barrier Reef depends on how quickly we address human-made pressures like climate change and try to reduce greenhouse gas emissions. This place is among the most diverse and iconic ecosystems on Earth. Sure, the media headlines have portrayed the reef as dying or dead, but that’s an oversimplification, it’s a bit more complicated than that. Let’s not write the reef off just yet.”

Read more:

The scientists stopped short of offering an explanation for the sustained Mangrove growth spurt, an explanation for why the Mangroves which were studied appear to be advancing so vigorously, but there is an obvious possible explanation.

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Tom Halla
January 11, 2022 10:07 am

As long as the coral grows faster than sea level rise, the island should grow. This is simple enough Charles Darwin figured it out in the early 1800’s.

Curious George
Reply to  Tom Halla
January 11, 2022 10:23 am

Let’s hope even PhD students in philosophy might understand it.

John W Brisbin
Reply to  Curious George
January 11, 2022 10:44 am

In a completely unrelated note, the Rainbow Warrior was seen performing routine hawser strength tests using isolated mangroves in the area.

Reply to  John W Brisbin
January 11, 2022 11:04 am

I’m trying to decide if “mangrove” is patriarchal.

Reply to  John W Brisbin
January 12, 2022 9:36 am

So, in order to save the reefs they were attempting to uproot the mangroves.
Hopefully they didn’t test their mooring lines while anchored to the reef.

Richard G.
Reply to  Rocketscientist
January 14, 2022 4:52 pm

Study Finds Parrotfish are Critical to Coral Reef Health

John in Oz
Reply to  Curious George
January 11, 2022 3:12 pm

And therefore as a stranger give it welcome.
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.

If ‘You are not a climate scientist’ is a valid argument for one side (the end-of -the-world climastrologists) then why is a philosophy student to be believed?

Reply to  Tom Halla
January 11, 2022 12:37 pm

The simplistic minds of what passes today as “climate scientists” simply cannot comprehend the well established notions of complex systems that constantly react to stabilize themselves … the “scientists” think very one-dimensionally such that “if the sea level rises the land and biological populations in the coastal margins will not respond, and will simply perish by drowning. It’s the same kind of simplistic reasoning they use to claim that the only factor that controls climate is CO2 concentration in the atmosphere, and nothing else.

Robert W Turner
Reply to  Tom Halla
January 11, 2022 4:26 pm

And evolved into the science of sedimentology and stratigraphy – which are completely ignored when it comes to the doomsday sea level rise pseudoscience.

Reply to  Tom Halla
January 12, 2022 6:12 am

And just 20 000 years ago with sea level 120 m lower the Great Barrier Reef could even not have existed on that same spot. Now let’s see. In a linear trend that would be 20 000y 120m = 200y 1,2m = 100y 0,6m. That is double of what they claim is happening today.

Reply to  Robertvd
January 12, 2022 7:51 am

From 16ky to 8ky ago sea level rose 100m which is 12.5 mm/y and yet reefs and atolls are still here today

Bryan A
January 11, 2022 10:09 am

Wow, imagine that, rigorous field study reveals better data than models…
Whoda Thunkit

January 11, 2022 10:12 am

I thought that mangroves always made the land grow. It is what they do.

And I suppose the reference to CAGW ensures the funding of more research.

January 11, 2022 10:19 am

Those mangroves collect the coral sand grains spit out by parrotfish, and coral bits washed in by storm surge. And over millennia, they do it just as fast as sea level rises or falls.

Curious George
Reply to  DMacKenzie
January 11, 2022 10:28 am

CO2 provides both a mangrove growth and a construction material for corals.

Reply to  DMacKenzie
January 11, 2022 11:30 am

Not actually “spit” out by parrot fish, but close enough for a family blog.

Reply to  Disputin
January 11, 2022 12:40 pm

Pooped out, actually.

Reply to  DMacKenzie
January 11, 2022 12:40 pm

In addition to capturing bits and pieces of coral reef, mangroves also generate biologic detritus (fallen leaves, and deadwood) that also collects within the root structure along with the sand, and forms “soil” that in turn supports more mangroves which create more soil which creates more mangroves and so on and so forth.

Bloke down the pub
Reply to  DMacKenzie
January 13, 2022 4:39 am

Just a thought, but do coral bleaching events lead to more material being available to be washed up onto these new islands? If so, they might be a necessary evil in the life cycle of the GBR.

Reply to  Bloke down the pub
January 24, 2022 3:03 pm

Bleaching events do not always produce dead corals.

Bloke down the pub
Reply to  ontherocks
January 24, 2022 3:06 pm

Agreed, but I don’t think I said they do.

January 11, 2022 10:47 am

Good job carefully selecting your words and sentences to not upset the climate (global warming) priests and their enforcers. You get to move to the next level with a caution letter though.

Peta of Newark
January 11, 2022 10:52 am

Holy H Cow – have these folks actaully stumbled upon the previous unknown prcess by which Soil Organic Carbon holds soils together – facititating niceties like agriculture, forestry, flood prevention, landslide aversions and myriad similar things

Isn’t Modern Science such a wonder and marvel?

But you know, often there is A Spoiler and, knowing me, you what that spoiler is.

Because, if what they seem to be saying is that the mangroves are growing more/faster than previously – The Enquiring Mind might wonder what the mangoes are using as raw material to enable their ‘island’ building operations.

The clue is in the main photo above. In fact its not even A Clue, its more noticeable the nose on most people’s faces
Yes/No = do you see it?

It the brown water in the foreground.
Okaaaaay, where did the brown water come from or how did it get to be ‘brown’

Soil Erosion

The brownesss of that water is caused by very fine sediments, in aqueous solution, and those very fine mineral partcles are, or WERE, the very most fertile part of farmalnd that maybe many 10’s or hundreds of miles away

Crunch time.
Which would you prefer – that those sediments were back on the farm growing food and fertilising crops, or out at sea creating photo-ops for tourists and jollifications for climate scientists?

No pressure from me, you’re on you’re own this time.

Reply to  Peta of Newark
January 11, 2022 12:09 pm

I’m guessing that the ‘brown’ water you see could be seen by others as sand through clear water..

Reply to  Peta of Newark
January 11, 2022 12:44 pm

I don’t know about elsewhere, but most of the brown water color surrounding Florida’s coastal mangrove forests comes from tannins released by the biodegradation of vegetation, both in the coastal areas and draining out of rivers to the estuaries. Most tourists and a lot of ignorant residents of Florida believes the brown color is man-made pollution and needs to be eliminated. But nature takes care of that via dilution, such that the brown waters only hang around the estuaries, but as you progress farther from the estuaries, the waters clear up to that famous aquamarine color along our sandy beaches.

Reply to  Duane
January 11, 2022 1:11 pm

Yes, Dr. Peter Ridd in Australia has published studies over many years about farm, dredging & industrial runoff along the east coast of Queensland, where the inner edges of the Great Barrier Reef are mostly over 100 kms from the coast.

Ridd finds that runoff suspended particles are so dispersed by the oceanic dynamics that ‘contaminants’ are undetectable anywhere near the inner GBR.

So the “activists” claiming that a coal mine which is a further 250 kms inland from the coast will deposit ‘pollution’ on the GBR are liars or lunatics. Usually both.

Reply to  Peta of Newark
January 11, 2022 7:30 pm

Sorry Peta, you are wrong again. Repulse bay is a large, 50 kilometer wide bay just north of MacKay. It’s waters are very brown with muddy water running from large areas of mangrove creeks along it’s shores on every ebb tide.

It was so named by none other than Captain Cook who found the bay waters far to muddy for eyeball navigation, & named it Repulse as it repulsed his efforts to get close to the shore to make accurate maps.

I suppose a little of that mud could be farm run off today, but there weren’t many cane farms in the area in Cooks day.

Oh & Peta, the mangroves are probably growing faster today, fed by all that beautiful CO2.

Peter Ridd was right of course. Fly over Repulse Bay on an ebb tide & you will see a distinct line where the dirty bay waters meet the clean tidal flow, running south to north outside the bay. A very little of this muddy water is picked up by the tide, but most is pushed back into the mangroves by the following 5 meter high tide. None of the dirty water gets very far off shore. A trip to Whitehaven beach on Whitsunday Island, not very far off shore would prove this to you.

Sorry Mr, very little of the reef is 100Km off shore. For much of it the very outer bits are less than 50 Km, but those strong tidal flows keep the dirty inshore water from reaching it.

Yes Duane we have similar events in places in Oz. The brackish Myall lakes are the color of tea, produced by the tannin, but the mud in mangroves is genuine mud.

For those who don’t know what these mangroves can be like, We used to use a creek running through a 30 acre patch of mature mangroves in a mainland bay just south of Shute Harbor in the Whitsunday islands as our cyclone bolt hole a resort islands boats for years. The creek was twisty, quite deep, a kilometer long & 20 meters wide.

We would point up stream, ready for the up to 8 knots flow of flood water, with each boat tied out for & aft to the mangroves on either side of the creek. We would chose big mangrove trees, with trunks from 600mm to a meter in diameter. We would have up to 10 boats up there. We never got any wave movement up there, & the wind was dramatically reduced. The run off flod was about 5 meters deep above high tide level.

The sand fliues were dreadful, bit I can’t think of a safer place to be in a cyclone, than a good boat up a good mangrove creek.

Reply to  Hasbeen
January 11, 2022 9:19 pm

Hi Hasbeen,
my first recollections of the GBR were gained in a flight from Brisbane to Port Moresby in December 1975.
Beautiful clear flying weather all the way, so much so that the pilot got permission to fly much lower than the usual 30k feet.
That was a majestic sight for about 3 hours.
Been to various places & islands on fishing & diving trips over the ensuing years.
The GBR is located at between 16 and 160 kms off the coast, depending where on the coast you’re departing from, according to the various maps and guides –

Peter Fraser
January 11, 2022 11:16 am

I lived on the foreshore of an estuarine environment for twenty years. The species of mangrove growing in great numbers in northern New Zealand provide a means for coastal accretion. The germinated mangrove seeds are exceedingly depth sensitive depending on where they take root on the littoral. There is a contour line below which they are unviable as the seedlings are under water for too long during each tidal cycle. Mangrove roots of established trees provide a natural sediment collection system which raises the littoral level sufficient for seedlings to become viable and the process repeats.

Reply to  Peter Fraser
January 11, 2022 12:21 pm

But Peter the “disappearing coastlines” panic merchants want you to believe their models rather than trust what your own lyin’ eyes have meticulously observed first-hand over 20 years.

You’re obviously going to need the services of a “Climate Communications” graduate.

(I believe they are in demand, but only if they work for free. Which most of them do.)

Reply to  Peter Fraser
January 11, 2022 9:01 pm

My guess is the last El Niño that exposed some of the reef above water made have something to do with increase Mangroves also.

Ron Long
January 11, 2022 12:00 pm

My wife and I walked along the waters edge in Punta Cana, Dominican Republic, and saw the geometry: barrier reef offshore by about 250 meters, and abundant mangrove patches growing up to 50 meters out from the waters edge. As we walked a school of bonefish followed along with us, we scared very small fish out from the shore and the bonefish ate them. This appears to demonstrate several things, like islands get bigger by several techniques and bonefish are clever rascals.

January 11, 2022 12:10 pm

Allow me to correct that last bit. They said

Sure, the media headlines have portrayed the reef as dying or dead, but that’s an oversimplification, it’s a bit more complicated than that. Let’s not write the reef off just yet.

They should have said:

Sure, the media headlines have portrayed the reef as dying or dead, but that’s just wrong,, it’s all really simple. The reef is thriving. Period.

Tom Abbott
Reply to  Mike Jonas
January 11, 2022 12:43 pm

That’s what they should have said if they wanted to be honest.

Robert W Turner
Reply to  Mike Jonas
January 11, 2022 4:35 pm

Not to mention that the existential threat to the GBR [fate] is the return to a glacial period and there is nothing we can do to stop it.

Reply to  Mike Jonas
January 12, 2022 12:22 am

Record high coral.

michael hart
January 11, 2022 12:12 pm

“A field expedition to investigate remote islands on the Great Barrier Reef has discovered the islands are growing.”

Nice work, if you can get it.

January 11, 2022 12:17 pm

Would be hard to find an ecosystem that CO2 fertilization did not benefit.

January 11, 2022 12:19 pm

“ The scientists stopped short of offering an explanation for the sustained Mangrove growth spurt, ”

It would be heresy to mention CO2 fertilisation….

January 11, 2022 12:33 pm

This result should not be surprising at all to anyone familiar with botany and coastal biosystems, specifically mangrove forests.

Here on the Gulf of Mexico coast of Florida, we have the world’s second largest continuous mangrove forest. The barrier islands and mainland coast and riverine estuaries with these mangroves are continuously growing. It’s what mangrove does unless and until it either gets flooded too long with seawater in a large storm surge event associated with tropical cyclones (hurricanes here), or during prolonged freezes during periodic wintertime cold front passages. But even after those events knock the forest back a bit, it continues its inexorable march of creating more land.

For those not familiar with mangroves, there are several varieties that live at various points in the coastal ecosystem. As the mangrove grows (about 4 feet per year here in Florida), it sends out large intertwining taproots which act to provide cover for juvenile fishes and also captures sand and biologic material that over time creates “land”. Additionally, the mangrove constantly produces floating “propagules” that look like elongated bobbers that fishermen use. They float around with the tides and waves until they encounter a calm water area, then send roots down .. or they can go dormant if washed ashore until rehydrated later.

All in all mangrove forests are extremely resilient and will keep growing and expanding as long as they’re not cut down and removed by humans.

Combined with coral reef growth and propagation, mangroves continuously build new land in coastal shallows.

Chris Hanley
January 11, 2022 12:41 pm

The SMH:

PhD student Oxana Repina says the research is now more important than ever.

The quote above:

PhD student in philosophy [?] Oxana Repina says the research is now more important than ever.

In any case of course young Oxana says that, it is her future career she is taking about viz. the study of the GBR under constant and eternal threat.

January 11, 2022 12:58 pm

The Mangroves are on the march, as long predicted. Once they are done colonizing the reef islands they will move ashore and assault the coastline. They will pause only briefly to consolidate their gains before attacking again. The next target will be the coastal cities. Perth, Darwin, Canberra are all at risk. These Mangroves mean war, and they cannot be stopped. Like the rising ocean itself, they are relentless, always on the move, invincible.
Pray for Australia.

Reply to  TonyL
January 11, 2022 1:17 pm

They sound just like cane toads.

Reply to  Mr.
January 11, 2022 9:04 pm

It amazing how the predators figure cane toads underside has taste tidbits with out the poison.

Ben Vorlich
Reply to  TonyL
January 11, 2022 1:39 pm

Read that comment and thought of this from my student days

Barry James
January 11, 2022 1:12 pm

Isn’t it amazing how the dyed in the wool alarmists who now populate universities like JCU and others like them and dominate research on the GBR simply cannot help themselves. In spite of lots of hard evidence that the GBR is thriving they insist on touting their imaginary “catastrophic global warming” and subsequent bleaching and “acidification”. They persist with their doom and gloom narrative that requires hundreds of millions of our money to be thrown at it so they can “Save The Reef”. The disasters they are predicting don’t appear to be happening so more research is required to find them. It is totally unacceptable that their narrative could simply be wrong.

Chris Hanley
January 11, 2022 1:18 pm

According to the Great Barrier Reef Authority “the earliest evidence of complete reef structures to have been 600,000 years ago” (Wiki).
Australians were vaguely aware of the Great Barrier Reef and the Coral Sea in the 1940s and 50s mostly because of the sea battle in 1942 that supposedly ‘saved Australia’ from Japanese invasion.
It was only from the 1960s when snorkeling became popular that the GBR gained popularity as a tourist destination.
It was in the mid 1970s when the GBR was declared a marine park and protected by legislation that opportunities for careers like a constant holiday became available to budding marine scientist.

Reply to  Chris Hanley
January 11, 2022 6:05 pm

The Battle of Coral Sea did not “supposedly save Australia from Japanese invasion” … it DID save Australia from Japanese invasion via eastern Papua New Guinea.

Chris Hanley
Reply to  Duane
January 11, 2022 7:46 pm

‘Supposedly’ means: ‘believed to be the case but not necessarily so’.
Opinions differ, regarded by some historians as a parochial view.

Reply to  Chris Hanley
January 11, 2022 9:09 pm

Question what the the GBR do in the last ice age. It had to be sitting out of water, by a long ways. It did not “die” it was just uninhabited at that time. The residents had to have come back when the water returned. Our our educated idiots really that stupid not to know this.

Last edited 1 year ago by MAL
Reply to  MAL
January 12, 2022 8:01 am

Yep. They are.

January 11, 2022 2:06 pm

It looks, yet again, as if that old devil CO2 is doing the improvement again. There is no part of the World ecosystem that CO2 fertilization is not benefiting.

Jim Mundy
January 11, 2022 2:09 pm

My family and I got an object lesson in the fact that plants can essentially create land, while we were stationed on Guam 1980-1983. Sometime during our second year there, a coconut got lodged in a small patch of coral sand in the reef at Tumon Bay and took root. By the time we left, it had created about a 10-15 foot diameter island around itself as its roots stabilized the sand and held new sand. A few years later I was back on Guam for a typhoon conferenced and noticed that the island had grown to about 30 feet wide and 80 feet long.

January 11, 2022 4:38 pm

That coral bed had to be growing long before the first mangrove took root. It’s an indication of the years of bad science uttered as fact by the coral reef doomers.

January 11, 2022 4:51 pm

Remember the late Dr Nils-Axel Morner a notable scholar of global sea levels – who circa 2007 reported how a tree had been cut down in the Maldives. This was a tree standing offshore and he said a group of Australian students/visitors were responsible.

January 11, 2022 4:54 pm

One of the more enjoyable threads of late. I’m sure the natural world is much more resilient than the alarmists believe; we just have to wait for them to be proved wrong.

Andy Pattullo
January 11, 2022 7:47 pm

Remarkable the apparent
lack of insight in supposedly scientific minds. That they find evidence exactly contrary to their favourite theory and then pretend it is evidence in support or at least an excuse to maintain the theory is a sign of total incompetence, fraud or both.

Harkle Pharkle
Reply to  Andy Pattullo
January 12, 2022 8:56 pm

“It is difficult to get a man to understand something when his salary depends on his not understanding it.” — Upton Sinclair

January 11, 2022 8:55 pm

I had a person who told me the Great Barrier reef is gone last year. She was suppose to be a collage educated person. To much alphabet network watching and source of her information is my diagnosis as her problem. Her so called education(indoctrination) may have not help either.

January 11, 2022 9:32 pm

Australia’s present day coastline is much smaller than it was …

January 11, 2022 10:58 pm

Mangroves are the weeds of the ocean, they’ll grow anywhere and everywhere!

January 12, 2022 2:24 am

And just 20 000 years ago with sea level 120 m lower the Great Barrier Reef could even not have existed on that same spot. Now let’s see. In a linear trend that would be 20 000y 120m = 200y 1,2m = 100y 0,6m. That is double of what they claim is happening today.

January 12, 2022 3:24 am

More CO2, more plants. It ain’t rocket surgery, chi’drens.

January 12, 2022 4:06 am

Here are the mangroves of North Caicos, doing what mangroves always do, trapping sediment and growing out into the shallow waters of the lagoon.

Of additional interest is that mangroves growing in the sheltered lagoon fringes of coral islands accually create calcareous mud sediment because the surface of their roots below water provides a holdfast for calcareous algae that create and mechanically shed micrite crystals.

Matthew Sykes
January 12, 2022 4:59 am

Blah blajh blha, nothing bad happening, islands fine. etc, then

Standard disclaimer, climate change is dangerous and we mush do something.

Pathetic, isnt it.

glenn holdcroft
January 12, 2022 6:42 am

So global warming “Climate change” creates mangrove islands on ‘disappearing’ reefs .
It is a miracle molecule indeed .

January 13, 2022 3:16 pm

If you don’t mine the hell out of coral the islands will grow –
“Paper 5: Status of Coral Mining in the Maldives: Impacts and Management Options – By Abdulla Naseer, Marine Research Section, Ministry of Fisheries and Agriculture Malé, Republic of Maldives”

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