Effect of CO2 on the oceans alkilinity

[antonsemrad]

Does the added CO2 in the worlds oceans affect alkilinity? If so, how? If not, what has been the alkilinity of NSW historically speaking? (has it changed)

Thanks
Anton

 

[Boomer]

No, CO2 is independent of Alk. CO2 does not affect Alk and vice/versa, but it will affect pH. However, the increase in CO2 can cause the dissolution of carbonates, due to the lowering of pH which will change the Alk causing it to rise like in a reactor. Alk in the world oceans is also dependant on land mass and what they add to the oceans.

Here are some plots of recent years;

nTA = Total Alkalinity

DIC (Dissolved Inorganic Carbon) = All the CO2 + all the HCO3- and CO3-- that can be converted into CO2.

pCO2 = Partial pressure of atmospheric CO2. The higher the pCO2 the more CO2 there is in both the atmosphere and the ocean waters.

http://www.bbsr.edu/Labs/co2lab/research/IntDecVar_OCC.html#tab1

There are studies being done on Barium concentrations, which act as Paleoceanography indicators of ancient ocean Alk. The ALk has changed both up and down the scale in millions of years

 

[antonsemrad]

thanks a bunch boomer

looks like I have some reading to do.

 

[antonsemrad]

I would like to see some graphs that go back before the industrial revolution.

Oh and how do you translate nta to meq or dkh?

 

[Boomer]

2380 = 2.380 meq / l. Usually values by chemical oceanographers are in µmol / kg. Same for the DIC.

 

[antonsemrad]

So the alkilinity is on a upward trend, but the ph is downward.

So are we going to add a bunch of calcium/carbonate to the oceans surface waters to offset the drop in ph, and sink more c02?

 

[Mike O'Brien]

Here is some reading to confuse you further.

http://www.ucar.edu/communications/Final_acidification.pdf

 

[antonsemrad]

Yep its confusing me.
But great link. I dont think I can get through it all at once. But I will read it all.

Thankq very much.

 

[Boomer]

Nice pdf Mike :thumbsup:

 

[Mike O'Brien]

Thank's.

I was talking to Borneman about this a few week's ago and he gave me the link. He say's that Pre industrial revolution the alkalinity was higher, I said CO2 can't effect alkalinity. He gave me that. LOL

 

[Boomer]

Eric makes allot of chem errors. As I said and it can be proven with a glass of water that CO2 does not effect Alk. I guess all those chemical oceanography books I have are wrong :lol: Tell Eric that he needs to tell, the worlds leading expert on the CO2/Carbonate System in seawater, Dr. Frank Millero, that he does not know what he is talking about.. For that matter, Randy and I are also wrong.

CO2 lowering the pH and dissolving carbonates and then raising the Alk is not the same thing. That is how a Calcium reactor works.

Some handy ref books that usually shut someone up

CO2 in Seawater: Equilbrium, Kinetics, Isotopes, by Zeebe & Wolf-Gladrow, 2005

Carbon Dioxide Equilbria and Their Applications, by Butler, 1991

Ocean Biogeochenical Dynamics by Sarmiento & Gruber, 2006

An Introuction to the Chemistry of the Sea, by Pilson, 1998

Chemical Oceanography by Millero, 2005

Aquatic Chemistry Concepts by Pankow, 1991

And many of those articles by Randy

 

[Mike O'Brien]

LOL, yes. I did post a sniplet from one of randy's articles.

 

[Mike O'Brien]

To keep this in context.

I said.

Ok, I am under the impression that average reef alkalinity is around 2.5 meq/l. I do however prefer to run my tank at 3.5 meq/l.

and

According to randy's article "what is alkalinity"

Well, the carbonic acid can release protons by reversing equations 1 and 2:

(5) H2CO3 ==> H+ + HCO3-

(6) HCO3- ==> H+ + CO3--

These protons can go on to reduce alkalinity by combining with something that is in the sample that provides alkalinity (carbonate, bicarbonate, borate, phosphate, etc). However, for every proton that leaves the carbonic acid and reduces alkalinity, a new bicarbonate or carbonate ion is formed that adds to alkalinity, and the net change in total alkalinity is exactly zero. The pH will change, and the speciation of the things contributing to alkalinity will change, but not the total alkalinity.

He said

I can add CO2, sodium carbonate or sodium bicarbonate to my tank and increase alkalinity. If I mix the carbonate and bicarbonate in the right proportions, my solution can equal the tank pH. If I then pour that same pH solution in the tank, I won't change pH but will increase alkalinity. OTOH, if I added carbonate (i.e. washing soda...am ignoring the sodium since it dissociates into the huge Na pool), the pH of a solution is around 11, so the pH and the alkalinity of the tank water goes up. The pH, in turn, shifts the equations below towards carbonate in the tank.

I can add CO2, sodium carbonate or sodium bicarbonate to my tank and increase alkalinity. If I mix the carbonate and bicarbonate in the right proportions, my solution can equal the tank pH. If I then pour that same pH solution in the tank, I won't change pH but will increase alkalinity. OTOH, if I added carbonate (i.e. washing soda...am ignoring the sodium since it dissociates into the huge Na pool), the pH of a solution is around 11, so the pH and the alkalinity of the tank water goes up. The pH, in turn, shifts the equations below towards carbonate in the tank.

What Randy is saying is that in a given volume of water with a given alkalinity, if you shift pH, you change from CO2 at low pH to CO3 at high pH.

Kalkwasser is calcium plus some hydroxides. The hydroxides raise pH and move CO2 in air and water towards carbonate. So, in this case, the OH, while containing no C, creates alkainity from CO2 when in solution (hence the CaCO3 crust that forms on the surface of kalkwasser solution).

And yes, it appears that the primary acidification of the ocean is the reason for the loss of carbonates. And this is where the terminology gets tricky, because at normal oceanic pH's, you have to see which species predominates. Near anoxic muds in mangroves..or in freshwater...you can calcify but the calcium carbonate dissolves. That's what is happening in the world oceans...decreased calcification and increased carbonate dissolution, but the latter is on longer time scales, so the release of dissolved carbonates does not balance the rate of acidification by CO2 input.

 

[Randy Holmes-Farley]

I can add CO2, sodium carbonate or sodium bicarbonate to my tank and increase alkalinity.

If that sentence is truly meant as written, it is obviously incorrect. The latter two increase alkalinity, but CO2 cannot.

People think about the bicarbonate that comes on dissociation and see a seeming rise in alkalinity:

CO2 + H2O ---> H+ + HCO3-

but they forget that the proton goes immediately on to either convert carbonate to bicarbonate, or bicarbonate to carbonic acid/CO2, both of which reduce alkalinity:

H+ + CO3-- ---> HCO3-
H+ + HCO3- ---> H2CO3 = H2O + CO2

 

[BeanAnimal]

before the industrial revolution huh.... you may want to look at the recent upward temp swing that all of the global warming nuts keep talking about... most of it came before the industrial revolution also

Ever wonder what kind of stuff those underwater volcanos spew into the ocean?

 

[Boomer]

Well all of that is pretty much correct accept the oceans are not loosing Alk or carbonates but gaining them. My graph pretty much proves that point. It is CO2 that is dropping the worlds ocean pH, coupled as he does say, that the dissolution rates can not keep up to increasing CO2 rates. If the ocean could keep up with the CO2 it would hit a balance at some point.

However, his CO2 addition in his tank is not doing anything to the Alk, it is those carbonates he is adding . The CO2 is changing the pH.

His kalk thing is similar to a reactor, as it is a chemical reaction taking place between to substances CO2 and OH addition from kalk.

 

[antonsemrad]

before the industrial revolution huh.... you may want to look at the recent upward temp swing that all of the global warming nuts keep talking about... most of it came before the industrial revolution also

A simple google search came up with this

I must admit, I get somewhat pessimistic about future predictions, but past records, not so much.

Perhaps in 50 years we will have a better idea about 'trends'.

 

[BeanAnimal]

The article is full of assumptions and conclusions that are nothing more than opinion that fit some of the data. That is the problem... Where are the articles that show that NONE of the warming models fit the data that is being collected? Where are the articles that show that the coming mini-ice age has nothing to do with the greenhouse gases and teh slowing of the mid atlantic current? There is PLENTY of science out there to explain these things, it does not fit the "mainstream man is evil" model and therefore it is not talked about.

try these http://www.warwickhughes.com/climate/ and http://www.oism.org/news/

What about our Senators Rockefeller and Snowe sending ExxonMobile an open letter DEMANDING that they stop funding research to disprove or discredsit global warming! So much for freedom.

The facts? They are so far burried in world politics, wealth redistribution agendas and outright nonsense that none of us could sort it all out. The media and "believers" have taken the stance that if you do not believe, you are a bad person and want the planet to bake into a wasteland.

All I know is that for every reputable scientist that claims "it is mans fault" another reputable scientists claims "it is natures way". Heck we are now calling it "climate change" becuase the global "warming" model no longer fits!!

This is certainly not something we are going to sort out on reef central... but the chemistry part of this thread is/was interesting. Even boomer and Randy differ on their explanation of just one small facet of this (if I read correctly) and both are well informed and educated with regards to chemistry.

 

[BeanAnimal]

Here is another one I found very interesting http://www.heartland.org/Article.cfm?artId=13695 Note the references etc...
We could dredge up a hundred reputable sources on both sides.. and that was not my intent. I just wanted to provide a bit of the "other side" as it may relate to your question and the answers already provided here.