The chemical equation:
Ca2+ + 2HCO3- = CaCO3 + CO2 + H2O
is often quoted as the equation for the formation of biogenic calcium carbonate.
Does anyone know its history or who first proposed this equation?
Ken,
The first case of its use I have found is in a paper dated 1982, where it is stated without justification. I wondered where they had got the equation from.
Berger, W. H. (1982) ‘Increase of carbon dioxide in the atmosphere during deglaciation: the coral reef hypothesis’, Naturwissenschaften, vol. 69, no. 2, pp. 87–88 [Online]. DOI: 10.1007/BF00441228.
While trying to find that reference for you, I mixed up the names Berger and Berner and found this later paper, by one year, which does give a source:
Berner, R. A., Lasaga, A. C. and Garrels, R. M. (1983) ‘The carbonate-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million years’, Am. J. Sci, vol. 283, no. 7, pp. 641–683.
The source is your and my old friend T. C. Chamberlin
Chamberlin, T. C. (1898) ‘The Influence of Great Epochs of Limestone Formation upon the Constitution of the Atmosphere’, The Journal of Geology, vol. 6, no. 6, pp. 609–621 [Online]. DOI: 10.2307/30054731.
Thanks for your help!
I checked out the Chamberlin paper and he did not write out the chemical equation, but he did write "Since a certain amount of carbon dioxide is associated with the mono-carbonate of lime in solution as the second or bicarbonating equivalent, and since the secretion and deposition of the lime takes place as the monocarbonate, the associated carbon dioxide is set free."
I am still interested to know who was the first to write out the equation, since it appears to be based on the old fashioned belief that calcium bicarbonate exists in solution with a formula Ca(HCO3)2.
The reason it matters is that the equation is wrong, but no one is going to take my word for that. I need to know how it came to be adopted.
Thank you Sigrid,
That book seems to have been translated into English as "Handbook of Geochemistry". Unfortunately it is not available in my local university libraries. Does he mention where he got the equation from, or does he just state it?
Hi Sigrid,
Amazon has second hand copies in English at prices ranging from £100 - 400, but I have found a copy for £5 including postage, which I have ordered.
Thanks for your help.
Prior to formulating the explicit equation, knowledge on the workings of biogenic carbonate formation has existed for quite some time.
Berner & Maasch (1996) report on the mid 19th Century contributions by Jacques Ebelmen. In quoting and translating Ebelmen (1845), Berner & Maasch (1996) write:
"The terrestrially-derived [dissolved] carbonates end up by being deposited or they are taken up by marine animals, molluscs and zoophytes. The alkali carbonates react with the calcareous salts contained in seawater, precipitating a proportional quantity of calcium carbonate."
Perhaps confusing is the reference to alkali carbonates in this quote, which is related alkali elements sourced from the weathering of silicates contributing to the dissolved ions in seawater, also discussed by Ebelmen (see Berner & Maasch (1996) for details).
Preceding modern notation of chemical reactions, Ebelmen (1845) demonstrated that he understood the core chemistry governing biogenic carbonate precipitation as well as from many other earth system relevant reactions.
Berner, R.A. and Maasch, K.A. (1996) Chemical weathering and controls on atmospheric O2 and CO2: Fundamental principles were enunciated by J.J. Ebelmen in 1845. Geochimica et Cosmochimica Acta 60, 1633-1637.
Thomas,
Thanks for that info, but what I really want to know is who first wrote down the equation. Finding the answer is a bit like looking for a needle in a haystack, so I was hoping I would find someone who knew straight off.
Sigrid,
Just to update you, the version of Wedepohl I had ordered was only Vol II, which comes in two parts. When I inquired about Vol I, I think they realised that they had under priced the book and cancelled my order :-(
I have now discovered a nearby university library which has Wededpohl, so I will probably pop along there soon.
Towe, K. M. and Malone, P. G. (1970) ‘Precipitation of Metastable Carbonate Phases from Seawater’, Nature, vol. 226, no. 5243, pp. 348–349 [Online]. DOI: 10.1038/226348a0. Would it be possible for you to send me a copy?
Ken,
I see you published a paper that seems relevant:
I have found an answer to my question in:
Garrels, R. M. (1965) ‘Silica: Role in the Buffering of Natural Waters’, Science, vol. 148, no. 3666, pp. 69–69 [Online]. DOI: 10.1126/science.148.3666.69.
He wrote:
"If these rocks are limestones, the classical reaction for weathering of calcium carbonate applies:
CaCO3(calcite) + H2O(l) + CO2(g) = Ca2+ + 2HCO3−"
So it seems the reaction is much older than 1965 when it was classical.
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