Thanks a lot, Kenneth, I am really impressed by Your overview, especially the citation from 1919...

The modern way of doing 'science' by relying on numerical modeling, is more like doing 'science' by asking the Oracle of Delphi for advice, which was an accepted way a couple of thousand years ago. It's back to the dark ages, it seems.

To me it seems possible that they get the flow from the dye concentration with time and the alkalinity uptake comes from how the measured remaining alkalinity match the dye concentration. 

There are so many other factors that could be effecting alkalinity, not just calcium uptake by corals, There are fish, plankton, algae, etc. But the real problem is in the abstract where they state "Here we quantify the net calcification response" when they didn't actually measure calcification rates at all. How this passes as respectable science is very disturbing.

Change in alkalinity has been used to compute calcification in reefs for decades, the so-called “alkalinity anomaly” technique, refer to seminal paper by Smith & Key (1975), that was applied (among several others) by Gattuso and co-workers in the 90's in several coral reef systems. This technique has also been used to estimate pelagic calcification in mesocoms (Delille et al. 2005) and at sea (Suykens et al. 2010). For a recent paper evaluating the “alkalinity anomaly” technique refer to Gazeau et al. (2015).

Delille et al. (2005) Response of primary production and calcification to changes of pCO2 during experimental blooms of the coccolithophorid Emiliania huxleyi, Global Biogeochemical Cycles, 19, GB2023, doi:10.1029/2004GB002318

Gazeau et al. (2015) Comparison of the alkalinity and calcium anomaly techniques to estimate rates of net calcification. Marine Ecology Progress Series 527:1-12

Smith & Key (1975) Smith SV, Key GS. Carbon dioxide and metabolism in marine environments. Limnology and Oceanography. 1975;20:493–495. doi: 10.4319/lo.1975.20.3.0493

Suykens et al. (2010) Dissolved inorganic carbon dynamics and air-sea carbon dioxide fluxes during coccolithophore blooms in the Northwest European continental margin (northern Bay of Biscay), Global Biogeochemical Cycles, 24, GB3022, doi:10.1029/2009GB003730

Thanks, Alberto,

this is interesting.

Hi Martin.

I would echo Alberto, in that alkalinity reduction has been more or less a standard method for almost a half-century. The underlying assumption is that any disappearing bicarbonate not evaporated with CO2 will have gone into calcification. Evaporation has been tackled and solved well enough.

As always, the devil is in the details. "Calcification" means every calcifying critter in the study area, not just corals. It will, for example, include any planktonic forams that happened by! But if you said/assumed that 90% of the alkalinity reduction was due to corals, benthic forams and calcareous algae, you would not be far wrong. My problem with the method is that it does not allow for alkalinity increases from the activities of boring algae-which, on a reef flat, are a major source of productivity.

But, in short-the method is off the shelf, pretty well standard.

Past episodes of ocean acidification are hard to characterise. There are large energy humps in dissolving shells, there are differences in solubility amongst the various mineral phases-and corals seem to have (viz. Mal McCulloch's recent work) the ability to up-regulate intracellular pH, thereby resisting acidic waters...

Ken Towe's statement about stable temperatures should not go unchallenged, because it is dead wrong. This favorite denier talking-point has been demolished so thoroughly I am surprised to see it crop up here. Those interested are encouraged to check out (among many)  Foster and Rahmstorf 2011 (ERL).

I will try to follow up on this paper- it does sound very theoretical and  "iffy"- please remember- I am not  a chemist....Kenneth Towe's answer is most reasonable

Charlotte

A bit on thin ice here, but from a geological record point of view the story seems farfetched.  PH Chemistry of the transformation of Aragonite - MG calcite -calcite in/on is very complicated and not fully understood  and probably no model can so far prove it. As a side step in your district you have fresh water mussels in rivers on Jæren which are awful acid :) - pearl bivalves: now protected and as understand currently a healty community.  Both evolution or adaption and biochemistry i.e. icehouse and greenhouse periods is of great importance.

Also transgression and regression is an important issue of for warm tropical water carbonate factories. Under max glaciation marine water is retreated to Deep Ocean and as a result; exposed carbonate platforms and ramps. Under Great Barrier Reef there are Pleistocene continental red beds. Bahamas platform becomes karstified.

During onset of the last eustatic sea level rise 170ppm atmospheric CO2 is suggested. I have not find any publication or an interpretation/models of  PH at that time – should be of interest.

This is a bit strange; While retrospective studies show large-scale declines in coral, and community, calcification over recent decades, determining the contribution of ocean acidification to these changes is difficult, if not impossible, owing to the confounding effects of other environmental factors such as temperature

Yes coral reef have problems but not due to Temperature, PH or CO2 level, but by us. see

http://www.unep.ch/regionalseas/main/persga/pilcher.html 

I also enclose in my view a good article (apologise to non-Scandinavians-  it is only in Norwegian)

Snorre

• PS not a denier of man made climate change, but see many strange arguments on CO2 cycles.

Thanks, Snorre, for an interesting answer,

I sincerely hope we are not discussing who is denier and who is not. This is not the subject. In order to understand what is going on in the Ocean, we need to DISCUSS - across all sorts of borders, both political and subject matter. - Snorre, I did not find the Norwegian article you enclosed...

This is not the forum for a discussion of climate change. You should not have introduced mention of the (debunked) "plateau" in a posting on calcification measures via alkalinity reductions-which is a standard technique.

There never was a plateau. UAH satellite measurements suggested there was one, a decade ago, but after their mechanical errors were located and corrected, their measures fall in line with all the others.

There is already a sufficiently toxic admixture of science and politics in your country-let's keep this board focused on science.

I didn't call you names, I said you were wrong-and you clearly are. (If you wish to be in front-line science you need a thicker skin.)

I see you have not read the references I suggested, and I see no need to continue this obviously fruitless argument.

Do you have anything useful to say about carbonate alkalinity?

Dear all,

I have now received the Norwegian article that Snorre tried to embed in his response above. I have also added it as a file (below). The article has the title:

"The Cosequences of lower alkalinity seawater" (Some geochemical considerations on the importance for life in the ocean). It was published in 'Biolog', no. 2, in 2011 (p. 28-33), by Knut Bjørlykke, Helge Hellevang, and Per Aagaard. Here is my translation of the introduction and parts of the conclusions:

From the intro: "The increased CO2-concentration in the atmosphere will cause a lower pH in the ocean because it dissolves in water and forms carbonic acid. The effect is dependent on the stability of different carbonate minerals. Calcium carbonate (CaCO3) occurs as a trigonal mineral, calcite, which is thermodynamically most stable. But, also aragonite is formed, which has a rhombic structure, and is less stable and has a higher solubility. Modeling has shown that the solution of aragonite will contribute to a less reduction in pH and that calcite will continue to remain stable in most areas. This will be the case especially in shallow areas and around coral reefs, but will most probably also have a global effect." 

From the conclusions: "Our modeling shows that the dissolution of aragonite is very fast and will be an important effect if CO2 in the ocean increases significantly. Aragonite-containing sediments occur even at high latitudes, for example off the Norwegian coast. This is a 'feed-back' effect which, up till now, has hardly been discussed in the current OA-literature. We will not state that OA does not have any effect (on marine organisms), but, the problem has to be discussed more thoroughly with respect to the geochemical balance in the ocean and take into account reactions that will reduce the degree of aragonite under-saturation. The tolerance of organisms for aragonite is, thus, important."

I should have known better. Debating those with thin skins and rigid opinions is never fun. Nonetheless, let me attempt to bring this back to where it started.

 Towe mentioned the by-now notorious "hiatus" in warming. I challenged him on that, because I felt that anyone knowledgeable in the field would know there had been no such hiatus-and I also felt answering Martin's question could have been done without introducing it.

 Much of the impetus for a hiatus came from the Univ. of Alabama at Huntsville (UAH) satellite data (as we have seen in the recent US Senate Circus). Beginning in the early 1990's, UAH published a series of papers suggesting that a lower rate of warming. Over time, so many other records began to accumulate showing pronounced warming, that others started looking at the original UAH data. Serious errors were found, including several in simple math...the new satellite records, properly corrected, are in agreement with other sources-but still the myth of the pause continues without pause...

 ...even though it has been thoroughly demolished. Below is a selection of recent papers, showing there was no hiatus, never was.

 Lewandowsky et al., 2015, Nature Scientific Reports

Carl et al., 2015 Science

Lewandowsky et al, 2015, Bull Am Met Soc

Foster and Abraham 2015

Meehl 2015 US Clivar

Foster and Abraham 2015 US Clivar

  I can do no better than quote Naomi Oreskes, from The Guardian Nov. 2015: "So the bottom line is: there is no pause, and there has never been one."

 So, you are wrong, full stop. Now, to the original focus of this post, the utility of alkalinity-reduction techniques and, by analogy, the survival of carbonate critters in acidic oceans.

 The concept of flow respirometry/alkalinity reduction goes back to Odum and Odum, that classic of classics. There is no doubt that, if you run a parcel of sea water over a reef flat, the alkalinity will go down. Simple stoichiometry then allows you to calculate how many moles of CaCO3 will be kicked out. But you need to remember just what is being measured. It is NOT reef calcification writ large, as painfully measured by skeletal growth etc. So those data need to be taken with a grain of sand. And, in the paper under discussion-the results did seem to be pretty obvious for Nature...add alkalinity to reef water, calcification goes up...one is tempted to say "duh."

 Projecting future survival of calcareous critters by looking at the record is tempting, but fraught. Experiments with organisms of varying mineralogy have shown startlingly variable results-I urge interested parties to read Anne Cohen's stuff. It has been suggested that pH changes in reefal environments will be buffered by HMC, but that (probably) fails on mass-balance aspects. Good further reading on this would be "Origin of Carbonate sedimentary rocks". James and Jones. The article that Martin has just added (thanks, Martin) says much the same...some (Barnes, etc) have argued that dissolution will buffer the shallows for decades, while others have argued (Buddemeier) that there just isn't enough HMC around...

 In any event, the geologic record is not encouraging. If the end-Permian event really was an OA crisis driven by volcanism, then keep in mind that it took the Scleractinia (modern corals) at least 10 million years to get going. I won't be around

And, Kenneth, the funny thing is that when marine scientists want to find out more about how CO2 affects organisms in the marine environment, they choose natural CO2 seep locations in the Ocean. Please read more about this in the final report of the 5-year long ECO2-project, conducted to find out more on the dangers of leakage from sub-seabed CCS-sites, here:

http://www.eco2-project.eu/

Just knowing that there are hundreds and thousands of natural CO2-seep sites around the world, hints that the Home Planet, is perhaps, one of the least known planets in the Solar system...

Yes, as a 35 year member of the safety panel of the Ocean Drilling Program (now it's called the International Ocean Discovery Program, see www.IODP.org), where we review each of the proposed drilling locations, I have grown up With (and listened to the world's experts on) what is going on in the deeps of the Ocean. It is, however, not only the 55,000 km long preading zones of the Ocean (the Mid Atlantic Ridge, Mohn's Ridge, the Gakkel Ridge, and all the other Ridges and spreading troughs), that produce these natural 'pollutants', including copious amounts of CO2, but also the many transform faults, subduction zones and many of the ca. 800,000 seamounts (defined as an underwater mountain that is over 1000 m tall, and most often represents a live or extinct submerged volcano), that also produce some of the methane, asphalt and CO2, etc.

However, we do not yet know what effect these deep-Ocean systems influence climate change and how they may transmit some of their enormous and varying energy output to the atmosphere.

For example: Have you ever seen a very good explanation for the semi-cyclic short-term climate driver: El Niño and LaNiña ? Some researchers think that some of this is triggered by tectonic unrest in the deep Pacific, for example the area near the Galapagos islands (the Carnegie Ridge).

Thanks, Kenneth,

this is interesting, but I am afraid we are getting on to another branch than the original question. My conclusion from what is discussed above, is that it is not possible (or at least reliable) to calculate or model calcification of Corals, based on flowrate and alkalinity measurements, as suggested in the paper by Albright et al., 2016.