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Author Topic: Would the calcium carbonate buffer break in the ocean with increasing CO2, When?  (Read 2174 times)

Offline Chondrally

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At 878 ppm CO2 in the atmosphere, most likely around 2054, the calcium carbonate buffer in the ocean will begin to break!

The following links are topical for environmental and civilization sustainability.  The first one is about the breaking of the magnesium  buffer in the ocean at 493 ppm of CO2 in the atmosphere and how this will affect the pH of the ocean,  and how this in turn will affect the base of the food chain in the ocean, threatening life on the planet in a severe way.  The second is about a possible solution to the problem, creating a super efficient natural gas- solar engine that emits no CO2,  and that could revolutionize energy and transportation globally.  The west probably won't do it due to the power of the oil cartels and auto companies and their cash cow status quo.  But China and india might do it,  forcing the west to follow suit.

http://www.thenakedscientists.com/forum/index.php?topic=53181.0
http://www.thenakedscientists.com/forum/index.php?topic=53180.0




When the calcium carbonate buffer begins to break at 878 ppm CO2 in the atmosphere at sea level,  around 2054 annum,  the ocean will start to off gas CO2 into the atmosphere in small quantities at first leading to  large quantities eventually and stop overall absorbing CO2.  Deep ocean currents will well up from the depths and off gas CO2 into the atmosphere more often after this date than previously for a net weather effect.

Around 2070 annum, at around 1380 ppm CO2 in the atmosphere a serious nonlinearity in the equations governing diffusion and CO2 in the atmophere occurs,  and a sharp pH change will occur in the next 10 years affecting all life in the ocean, and possibly all life on the planet because of ecosystem linkages and the interconnectedness of the food chain.  Weather will be affected.   Unless something drastic occurs in technology before then to prevent the further net emission of CO2 into the atmosphere from the economy, reforestation, and population checks due to developing world initiatives.

The  engine mentioned in the Technology section of naked scientists.com that is super fuel efficient and emits only trace waste gases including no CO2 to the atmosphere while emitting trace amounts of carbon monoxide and nitrous oxides,  with no net O2 consumption from the atmosphere could really help the situation to save the oceans,  but it would be possibly harmful for the oil economy and global stability.  It is a challenge of the 21st century to ensure economic stability and achieve a technologically safe earth that isn't harmful to the creatures that live here.  It would be a bad metaphor to our future if we went to the stars but our home world died because we couldn't figure out how to save her in time!  The knowledge is available,  we need political will and international cooperation and trust to solve this problem.






the pH solution that is  presented is essentially a mass and charge balance.

The forecast for the ppm CO2 in the atmosphere from Scripps Oceanographic institute is begun with,   A longer term forecast is carried further out to 2100, assuming we continue as we are going..... which we wont , as there will be improvements like the blue diesel mentioned by Audi, and my engine which is zero CO2 emissions......

http://www.thenakedscientists.com/forum/index.php?topic=53180.0



however, its the most prudent guess right now.

Then the GT-C(mass of CO2 carbon)  in the atmosphere is solved for based on (Boyles Law)PV=NRT and gravity and density with height.

Then the ppm CO2 at sea level is used and an iterative solution of the diffusion equations for equilibrium at the surface is carried out. Solving for equilibrium using gravity and pressure and temperature and salinity gradients with depth and solving the ksp solubility product equations for the concentrations of ions with depth at the balance CO2 concentrations and the buffer equations is carried out.... to get the pH with depth. Very small discrete steps with depth were used, and quite a bit of effort went into finding a good and accurate step size.

The average of all the pHs over 1000 metres to get an average pH in shallow is reported.

ksp solubility product equations are actually behaving like 3D or 4D hyperbolas depending on the formula. Normally, as you start out on one section of the hyperbola, the gradient for the pH is always decreasing as CO2 increases, but as it passes the knee of the hyperbola, The concentrations of the buffer equations all start to behave differently in a nonlinear manner.

When this happens, the pH increases instead, and can increase quite dramatically over short periods of time or even decrease dramatically as the case may be.Another way to look at it is that there is a pool of ions fed from 2 or 3 reactions that cascade when the equilibrium is broken by the injection of carbonic acid ions into the solution. This cascade neutralizes the acid by introducing OH- or hydroxyl ions into solution that neutralize or balance the pH.  Each buffer has a finite buffering capacity, and it is cumulative. Once the buffering capicity limit is reached we say the buffer is spent or broken. After this, the pH can change rapidly.

Once the buffer is broken,  the pH does react very differently after the knee of the hyperbola is passed and the buffer equations solution from the ksp solubility products behave very differently too..
 The capacity of the buffer to neutralize added acid or added base is compromised at that region of the curve.







When the chemical potential of a dissolved chemical species exceeds that of the same species in solid form then the system will deposit solid(precipitate-sea snow-calcium carbonate) until equilibrium is regained and thereby the system free energy is minimised.  Of course that is only one side of the equilibrating system that we are dealing with.  This was not modeled in this system,  and precipitation is always notoriously difficult to model and involves quantum mechanics and Chaos Theory..  Its time to focus on solutions that give us real hope.  We know the oceans will have a problem with pH and off gasing, affecting the food chain, life in the ocean, and the global weather.  Only solutions that can stop CO2 emissions,  while maintaining our standard of living and mobility will work.  The engine that emits no CO2 or is CO2 neutral is our best hope.  The natural gas -solar or nuclear hybrid engine that is super fuel efficient and only emits trace amounts of carbon monoxide and nitrous oxides and is oxygen neutral offers us real hope.  Lets hope saner minds prevail and that reason amounts to something.


The following buffers exist in the ocean:
CO2(g) + 2e- -> CO2(2-)(aq)      first of all 2 electrons are stolen and there is a charge balance in the ocean
                                              so this results in the buffers producing more protons to balance the charge
Mg(2+) + CO2(2-) <-> MgCO2    the magnesium and calcium carbonate buffers steal CO2(2-) and cause sea snow which drops to deeper depths where it redissolves back into Mg(2+) and CO2(2-) under pressure.
CO2(2-)+H+ <-> HCO2(-)          a proton is stolen, resulting in more  hydroxyl radicals than protons.....
HCO2(-)+H+ <-> H2CO2            another proton is stolen resulting in more hydroxyl radicals than protons.
So the net effect of carbonic acid is to first steal 2 electrons from the ocean,  resulting in buffers that either reduce the amount of hydroxl radical in the ocean or produce more protons to balance the charge.
next protons are stolen,  resulting in buffers that either replace the protons or reduce the hydroxyl radicals or reduce other negative ions in the ocean (most likely) resulting in a net surplus of hydroxyl radicals and a net increase in pH making the ocean more basic.  which is what the following data are saying in effect.
H+ + OH- <-> H2O    OH steals an electon from H2O and yields a proton and a hydroxyl radical affecting pH or
H+ and OH- combine and form H2O with a net charge change of zero to the charge balance.
Ca(2+)+2HCO2(-) <-> Ca(HCO2)2  the formation of magnesium and calcium bicarbonate and also its sea snow.
Boron ions, Sulphates (Sulphuric acid and Phosphates (Phosphoric acid).

Question 1:  Where do the 2 electrons come from?,  currents in the oceans and lightning. creating storms and charge imbalances.....
Question 2:  which species replace the charge in the charge balance?  most likely phosphates, sulphates and boron complexes and magnesium carbonate and calcium carbonate.
If the charge is balanced by other species,  then there will be an imbalance of H+ and OH- and H2O resutling in a pH imbalance.

It appears from the following data that the net effect of introducing gaseous CO2  in the ocean past 2068 and 1301 ppm CO2 in the atmosphere,  is that the ocean becomes more basic, higher pH without bound, also killing the ocean and all marine life, affecting the weather as well and the temperature.





shallow          
water         
minimum         
pH                  
SWS scale         atm       ppm
       Year   GT-C   
8.28114   1990   557.79   389.75
8.41723   1991   561.00   391.99
8.41583   1992   564.26   394.27
8.41476   1993   565.58   395.19
8.41369   1994   568.76   397.42
8.41250   1995   571.40   399.26
8.41116   1996   574.39   401.35
8.40956   1997   578.14   403.97
8.40813   1998   581.45   406.28
8.40660   1999   584.95   408.73
8.40515   2000   588.14   410.96
8.40386   2001   590.62   412.69
8.40209   2002   595.54   416.13
8.40051   2003   598.80   418.41
8.39907   2004   602.86   421.24
8.39761   2005   606.73   423.94
8.39629   2006   610.30   426.44
8.39504   2007   615.67   430.19
8.39371   2008   618.99   432.51
8.39272   2009   624.85   436.61
8.39161   2010   629.54   439.89
8.39074   2011   633.43   442.60
8.38985   2012   639.22   446.65
8.38903   2013   644.45   450.30
8.38810   2014   651.52   455.24
8.38734   2015   657.12   459.15
8.38668   2016   665.09   464.72
8.38642   2017   670.00   468.16
8.38637   2018   676.02   472.36
8.38669   2019   684.15   478.04
8.38743   2020   691.19   482.96
8.39066   2021   699.36   488.67
8.92461   2022   706.18   493.43
8.38663   2023   719.14   502.49
7.95567   2024   727.07   508.04
7.95439   2025   736.16   514.39
7.95318   2026   744.79   520.41
7.95181   2027   754.30   527.06
7.95013   2028   765.70   535.02
7.94947   2029   771.00   538.73
7.94706   2030   785.21   548.66
7.94489   2031   797.06   556.94
7.94238   2032   810.84   566.57
7.93954   2033   825.03   576.48
7.93807   2034   832.10   581.42
7.93484   2035   847.93   592.48
7.93087   2036   866.52   605.47
7.92747   2037   882.46   616.61
7.92411   2038   897.72   627.27
7.92128   2039   910.34   636.09
7.91768   2040   926.41   647.32
7.91288   2041   948.60   662.82
7.91015   2042   960.37   671.05
7.90614   2043   978.40   683.64
7.90069   2044   1003.50   701.18
7.89613   2045   1024.57   715.91
7.89208   2046   1044.04   729.51
7.88621   2047   1075.62   751.58
7.88244   2048   1092.84   763.61
7.87847   2049   1117.89   781.11
7.87419   2050   1143.85   799.25
7.8701   2051   1169.60   817.24
7.8662   2052   1194.00   834.30
7.8610   2053   1238.15   865.15
7.7958   2054   1257.33   878.55
7.8652   2055   1294.54   904.55
7.8610   2056   1325.47   926.16
7.8595   2057   1352.48   945.03
7.8575   2058   1398.60   977.26
7.8577   2059   1441.57   1007.28
7.8590   2060   1458.30   1018.97
7.8599   2061   1512.00   1056.49
7.8618   2062   1542.74   1077.97
7.8659   2063   1609.93   1124.92
7.8686   2064   1648.84   1152.11
7.8725   2065   1696.33   1185.29
7.8770   2066   1760.19   1229.91
7.8796   2067   1810.69   1265.20
7.8815   2068   1862.07   1301.10
8.5540   2069   1917.86   1340.08
8.5373   2070   1993.44   1392.89
8.5497   2071   2027.56   1416.74
8.5892   2072   2099.68   1467.13
8.6241   2073   2146.97   1500.17
8.7016   2074   2232.48   1559.92
8.7747   2075   2300.05   1607.13
8.9042   2076   2406.21   1681.31
9.0300   2077   2491.66   1741.02
9.1241   2078   2569.70   1795.55
9.2563   2079   2666.69   1863.32
9.3294   2080   2722.65   1902.42
9.4866   2081   2849.61   1991.13
9.6033   2082   2949.76   2061.11
9.7144   2083   3045.09   2127.72
9.8736   2084   3169.80   2214.86
9.9832   2085   3245.65   2267.86
10.2264   2086   3391.43   2369.72
10.5681   2087   3563.42   2489.90
10.8298   2088   3680.03   2571.38
10.9209   2089   3718.53   2598.28
11.4988   2090   3945.63   2756.96
11.9659   2091   4113.51   2874.27
12.2321   2092   4204.49   2937.84
12.9895   2093   4448.60   3108.41
13.5114   2094   4606.17   3218.51
« Last Edit: 29/05/2016 11:54:33 by Chondrally »


 

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