The Reef Ain't Dead

[GordMay]

Originally Posted by Davidla

I care more about pollution, than I do climate change, why? Because climate change causes governments to grow and seek to impose new taxes (carbon charges) on humans. Growing governments are a very bad thing and only provide for more restrictions on freedom ...
... Please stop focusing on the effects and focus on the causes.

Your opening and closing statements are ironically contradictory. Would be quite humorous, if not so sad.
In your (erroneous) scenario, climate change would be the cause of (not necessarily) growing governments, and increasing taxes (the effects).
More generally, pollution AND climate change are the (putative) causes, motivating (some) governments to take (some) actions (effects).

[GordMay]

I suspect that Raymond may have miss-read, what I wrote - but that's OK, because his observations, and some scientific studies, contradicts (or adds to) some of what I wrote.
It's complicated, and I'm certainly no expert, so I apologise, for any confusion I may be adding to the discussion.


"... Reefs grow best where there is lots of water movement (among other things). Hence, fringing reefs are usually better developed on the windward sides of islands, than on the leeward (sheltered) sides. Once sea level has risen to cover a low hill, material, eroded from the reef, is carried from its windward side, to the more sheltered side, where it builds up.
Thus, although corals grow best on the windward side of reefs, the reefs themselves grow fastest on their leeward side..."
See ➥ https://www.aims.gov.au/docs/project...-thousand.html

But, it’s much more complicated than that.

For instance, a study[1], into the recent history of the Great Barrier Reef, has shown how it responds to rapid sea-level rise, and other environmental stresses. The study, conducted at the University of Sydney's research station at One Tree Island, contradicts the established model of Holocene-era reef growth.

Sea level, surface temperature, sediment in the water, nutrient influx and energy inputs into the reef system, all affect its vulnerability to environmental change. The reef system survives, because of a delicate balance of these environmental factors.

Three phases of growth

1. Clear water, fast growth
Between 1000 and 700 years after the continental shelf was flooded, corals started to grow, rebuilding the reef after a 100,000-year hiatus. Up to about 8000 years ago, the first corals to grow around One Tree Island were mostly shallow, clear-water and fast-growing, with a vertical reef growth of about 6 millimetres a year.

2. Slower, deeper growth
Between 8000 and 7000 years ago, reef growth slowed as waters continued to rise quickly. Temperatures rose and the quality of the water also changed in this period with an increase in sediment and nutrients. The types of corals were massive in form, sediment-tolerant and growth was deeper, at times up to 5 metres below sea level.

3. Catch-up growth
A slow-down and stabilisation of sea-level rise led to a fast (5 millimetres a year) vertical growth until the reef caught up to current sea levels about 6000 years ago. Growth in this period was mostly composed of shallow, branching coral assemblages.

New model of reef growth

A surprising result of the research is evidence that initial reef growth occurred on the low-energy, leeward side of the reef, ahead of growth on the high-energy, windward side.

This is contrary to established models of reef growth. In those models, the part of the reef exposed to higher energy inputs from waves and wind were thought to have been cleared of land-based ecosystems, clearing the way for reef development.

The paper proposes a new model, that needs further testing, in other regions of the Great Barrier Reef, and reef systems around the world.

What it seems to establish is, that the more protected parts of the reef might have been more suitable for early coral development.

“A new model of Holocene reef initiation and growth in response to sea-level rise on the Southern Great Barrier Reef”~ by Kelsey L.Sanborn et al
[1] ➥ https://www.sciencedirect.com/scienc...37073819302088

See also ➥ https://coraloha.weebly.com/coral-re...-overview.html

[Exile]

So obviously lots of complex factors which contribute to the rate and size of reef and coral growth. This also seems to confirm a high level of adaptation to different variables, including water temperature. But what about the causal connections between reef death, or bleaching events where coral recovers? If this is being blamed primarily on AGW, then warmer water temps and lower ph must be significant if not primary drivers, no?

[GordMay]

Originally Posted by Exile

So obviously lots of complex factors which contribute to the rate and size of reef and coral growth. This also seems to confirm a high level of adaptation to different variables, including water temperature. But what about the causal connections between reef death, or bleaching events where coral recovers? If this is being blamed primarily on AGW, then warmer water temps and lower ph must be significant if not primary drivers, no?

I'm not certain what it is that you're implying, and am certainly not a reef authority; but I'll answer with a 'qualified' yes (IMO).

However, FWIW:

The impacts of climate change, on our oceans, includes (but is not limited to) shifts in temperature, acidification, deoxygenation and changes in ocean currents.

About 90% of the excess heat, trapped by atmospheric greenhouse gases, is eventually soaked up by the world’s oceans. Because oceans are so big, the temperature change, to the seawater, can seem small, The sea surface layer has warmed by just over 0.5C, in the last century. That’s still enough to cause significant disruption, and the warming is accelerating.
Just like on land, rising temperatures, in the oceans, generate damaging heatwaves. They occur when unusual weather conditions, or currents, cause above-average water temperatures, for at least five consecutive days. But they can last for months, or even years. A marine heatwave called “The Blob”[1] hung around the northern Pacific, from 2013-2015, and killed as many as a million seabirds, on the west coast of the United States.

As carbon dioxide dissolves in seawater, it reacts to form carbonic acid: a fairly weak acid, but enough to alter the pH of seawater, which is naturally alkaline. Since the industrial revolution, dissolved carbon dioxide is estimated to have lowered the average pH, of the top layer of the oceans, by 0.1 pH units, from about 8.2 to 8.1 (7.0 is neutral). That change may not sound like much, but, because pH is measured on a logarithmic scale, it actually represents a nearly 30% increase in acidity (decrease in pH, a rate not observed in 300 million years).[2]
The increase in acidity is particularly bad news for shellfish, and other forms of sea life, that use the mineral calcium carbonate, to form their shells and exoskeletons. Ocean acidification can slow the growth of coral skeletons, and make reefs more brittle, and less resistant to stressors, like warming water temperatures.
More acidic water can hold less of this mineral, so there’s less available for calcifying organisms such as oysters, clams, sea urchins, calcareous plankton, and shallow & deep water corals. Worse, the change in chemistry encourages existing carbonate structures to dissolve.
Coral is particularly vulnerable. Experiments, on a small patch of Australia’s Great Barrier Reef[3], show that artificially reducing the seawater carbon dioxide level, so restoring pH to pre-industrial levels, boosted coral calcification by 7%. Then, when the scientists raised the amount of carbon dioxide, and so decreased ocean pH, to the level expected by the end of this century, calcification dropped by a third.


[1] “The Blob” ~ US National Park Service
➥ https://www.nps.gov/articles/theblob.htm
and
“How Marine Heatwaves are Changing Ocean Ecosystems” ~ NPS
➥ https://www.nps.gov/subjects/aknatur...murrewreck.htm

[2] “A Primer on pH” ~ NOAA/PMEL
➥https://pmel.noaa.gov/co2/story/A+primer+on+pH

“CO2 and Ocean Acidification: Causes, Impacts, Solutions” ~ Union of Concerned Scientists
➥ https://www.ucsusa.org/resources/co2...-acidification

[3] “Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms” ~ by Jeffrey B. McQuaid et al
Abstract only ➥ https://pubmed.ncbi.nlm.nih.gov/29539640/
Sorry, I (or Nature magazine) seem to have misplaced this study, but here’s an article about it:
“Landmark experiment confirms ocean acidification’s toll on Great Barrier Reef”
➥ https://www.nature.com/news/landmark...ef-1.19410#/b1

[Exile]

Worth a lot actually, and most helpful. Explains some of the science relevant to slowing coral growth, although not so sure about the relationship to the claimed increase in bleaching events, some of which results in coral death. Bleaching seems to be at the core of the controversy re: Prof. Ridd, namely whether, how much, and why this has increased as a result of the impacts of AGW.

No implications intended, only trying to make the point that the issues being discussed in this thread are not amenable to the sort of simplistic, binary, "believer/denier" analyses we so commonly see from other posters. Whether an expert or layman, one doesn't have to "deny" AGW to question -- or even express skepticism -- about its impacts. Nor should someone be labeled a "denier" (or anything else) simply because one questions the viability of the proposed remedies for addressing such potential impacts. It's not only inaccurate, but also deceptive and divisive.

[GordMay]

Originally Posted by GordMay

...[3] “Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms” ~ by Jeffrey B. McQuaid et al
Abstract only ➥ https://pubmed.ncbi.nlm.nih.gov/29539640/
Sorry, I (or Nature magazine) seem to have misplaced this study, but here’s an article about it:
“Landmark experiment confirms ocean acidification’s toll on Great Barrier Reef”
➥ https://www.nature.com/news/landmark...ef-1.19410#/b1

Good news! I found a version of the study:
“Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms”
➥ Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms | Roscoff Culture Collection

[GordMay]

Originally Posted by Exile

... one doesn't have to "deny" AGW to question -- or even express skepticism -- about its impacts.
Nor should someone be labeled a "denier" (or anything else) simply because one questions the viability of the proposed remedies for addressing such potential impacts. It's not only inaccurate, but also deceptive and divisive.

The fact(s) of AGW, it's likely impacts, and proposed remedies, represent three very different issues.
Many of those, skeptical of AGW & it's impacts, get labelled "deniers" because their, so-called, skepticism is almost entirely based upon their ideological aversion for almost ANY proposed remedy.
Yes, many of us are divided by our world view (ideologies). This cannot change the facts, of any matter.

[Lake-Effect]

^^^ what Gord said. If someone's 'skepticism' is based on misinformation, political bias - including a prejudice against taking collective responsibility and action, or refusal to genuinely understand or engage with the science, how is that not denial?

[RaymondR]

The term "denier" was deliberately chosen by the AGW/CC zealots to equate CC/AGM skeptics with those who deny the historical fact of the murder of millions of people of the Jewish faith during WW2. The quite deliberate intent was to morally locate the AGM/CC skeptics with the monstrous perpetrators of what is known as The Holocaust thereby making it explicit that the "climate change deniers" share the same severely degraded morality as those who challenge the historical facts of The Holocaust. Not very civil of them and a deliberate appeal to emotions rather than reason, but hey mate that's the way extremest often work.

The use of the terms "proponents", "agnostics" and "skeptics" would tend to be a bit more civil and perhaps more precise in the description of the breadth of opinion on the subject of AGW/CC.

In discussing ocean acidification and it's effect upon reef building one should remember that these structures are primarily built from CO2 combined with dissolved minerals from the sea water. Maybe the little marine dwelling buggers will just get there butts into gear and go on a reef building spree as the CO2 portion in the atmosphere increases.

[StuM]

Originally Posted by RaymondR

In discussing ocean acidification and it's effect upon reef building one should remember that these structures are primarily built from CO2 combined with dissolved minerals from the sea water. Maybe the little marine dwelling buggers will just get there butts into gear and go on a reef building spree as the CO2 portion in the atmosphere increases.

Whether coral reefs are net sinks or sources of CO2 is a moot point


e.g.

https://www.terrapub.co.jp/e-library...ta/pdf/229.pdf
"Because of dominant carbonate productionin coral reef ecosystems, most coral reefs are likely to act as a net or at least a potential CO2 source to the atmosphere."

[Exile]

Originally Posted by GordMay

The fact(s) of AGW, it's likely impacts, and proposed remedies, represent three very different issues.
Many of those, skeptical of AGW & it's impacts, get labelled "deniers" because their, so-called, skepticism is almost entirely based upon their ideological aversion for almost ANY proposed remedy.
Yes, many of us are divided by our world view (ideologies). This cannot change the facts, of any matter.

Absolutely false that use of the denier label is limited to those who oppose ANY proposed remedy. Certainly not on these threads, as well as in the wider world. As you say, in the broadest terms there are three major components to the AGW issue, and Nos. 2 (impacts) & 3 (remedies) do not have the same level of scientific consensus as No. 1, namely the fact that AGW exists. The problem is that the denier label -- like all such over-generalizations & stereotypes -- make no such distinctions, drastically oversimplifies the issues, and appeals to peoples' emotions, in some cases to the level of religious zeal. In fact, applied in this manner it necessarily results in the absurdity of labeling a significant portion of climate scientists themselves as "deniers," as well as a growing number of environmentalists who have come to recognize the folly of advocating for the use of solar and wind as a viable replacement for fossil fuels.

As Raymond has pointed out, this label must have been chosen deliberately, since it's hard to imagine anyone with any awareness of modern history not associating it with the Holocaust and the consistent attempts by anti-Semites around the world -- most notably the govt of Iran -- to use it as a weapon against Jews and the state of Israel. If the impact of AGW is indeed an existential or even serious threat to humankind which justifies profound changes to our economies, then I cannot imagine a worse way to build the necessary public consensus to accomplish it. It lends no insight, lucidity or credibility to the scientific debate or its policy implications, and appeals only to the most basic tribal instincts to try and win adherents.

Originally Posted by Lake-Effect

^^^ what Gord said. If someone's 'skepticism' is based on misinformation, political bias - including a prejudice against taking collective responsibility and action, or refusal to genuinely understand or engage with the science, how is that not denial?

Substitute your use of the word 'skepticism' with ...

"unquestioning belief in AGW, its most alarmist impacts and severe socioeconomic remedies" ...

but leave the rest of your statement intact ...

and you'll have your answer.

[RaymondR]

Originally Posted by StuM

Whether coral reefs are net sinks or sources of CO2 is a moot point


e.g.

https://www.terrapub.co.jp/e-library...ta/pdf/229.pdf
"Because of dominant carbonate productionin coral reef ecosystems, most coral reefs are likely to act as a net or at least a potential CO2 source to the atmosphere."

Hi Stu,

as someone who has drilled down through thousands of feet of carbonate rocks in my oil drilling days and being informed by various geo scientists that in forming these sediments it was primarily algae taking CO2 from the 7,000 ppm extant in the atmosphere and in doing so providing the great mass of O2 necessary for animal life on earth and vastly reducing the CO2 content I'm going with the sink hypothesis.

[Lake-Effect]

Originally Posted by RaymondR

as someone who has drilled down through thousands of feet of carbonate rocks in my oil drilling days and being informed by various geo scientists that in forming these sediments it was primarily algae taking CO2 from the 7,000 ppm extant in the atmosphere and in doing so providing the great mass of O2 necessary for animal life on earth and vastly reducing the CO2 content I'm going with the sink hypothesis.

Algae isn't coral, you've made no allowances for time factors, nor the "pressure" of 7000 ppm of CO2 and the resulting mix of lifeforms, and there's also this:

The formation of calcium carbonate by reef-building organisms causes the release of carbon dioxide into the surrounding environment. Hence, contrary to past belief, a reef mainly dominated by coral acts as a minor source and not as a sink of CO2 (about 1.5mmol CO2/m² day. Tambutté et al., 2011 for a review). Nevertheless, reefs still do play an important role as a carbon sink (as CaCO3), with rates of the order of 70 to 90 million tonnes of carbon per year (Frankignoulle & Gattuso, 1993).

[RaymondR]

Originally Posted by Lake-Effect

Algae isn't coral, you've made no allowances for time factors, nor the "pressure" of 7000 ppm of CO2 and the resulting mix of lifeforms, and there's also this:

Geologically corals are fairly recent newcomers so most of the mass of carbonates are probably laid down by algea.

However coral polyps build their homes from calcium carbonate CaCO3. If they get the calcium from the sea where does the carbonate come from?

[StuM]

Originally Posted by RaymondR

Geologically corals are fairly recent newcomers so most of the mass of carbonates are probably laid down by algea.

However coral polyps build their homes from calcium carbonate CaCO3. If they get the calcium from the sea where does the carbonate come from?

The sea.