seacarb (version 2.3.1)

pCa: pCa

Description

Calculates the changes in the saturation states of aragonite and calcite resulting from the manipulation of the calcium concentration

Usage

pCa(flag, var1, var2, Ca, S=35, T=20, P=0, Pt=0, Sit=0, k1k2="l", 
	kf="pf", pHscale="T")

Arguments

flag

select the couple of variables available. The flags which can be used are: flag = 1 pH and CO2 given flag = 2 CO2 and HCO3 given flag = 3 CO2 and CO3 given flag = 4 CO2 and ALK given flag = 5 CO2 and DIC given f

var1

Value of the first variable in mol/kg, except for pH and for pCO2 in $\mu$atm

var2

Value of the second variable in mol/kg, except for pH

Ca

Calcium concentration in mol/kg

S

Salinity

T

Temperature in degrees Celsius

P

Hydrostatic pressure in bar (surface = 0)

Pt

Concentration of total phosphate in mol/kg

Sit

Concentration of total silicate in mol/kg

k1k2

"l" for using K1 and K2 from Lueker et al. and "r" for using K1 and K2 from Roy et al. , default is "l"

kf

"pf" for using Kf from Perez and Fraga (1987) and "dg" for using Kf from Dickson and Riley (1979), default is "pf"

pHscale

choice of pH scale: "T" for the total scale, "F" for the free scale and "SWS" for using the seawater scale, default is "T" (total scale)

Value

• The function returns a data frame containing the following columns:
• comment
  The initial or final state water
• S
  Salinity
• T
  Temperature in degrees Celsius
• P
  Pressure in bar
• pH
  pH
• CO2
  CO2 concentration (mol/kg)
• pCO2
  pCO2, CO2 partial pressure ($\mu$atm)
• fCO2
  fCO2, CO2 fugacity ($\mu$atm)
• HCO3
  HCO3 concentration (mol/kg)
• CO3
  CO3 concentration (mol/kg)
• DIC
  DIC concentration (mol/kg)
• ALK
  ALK, total alkalinity (mol/kg)
• OmegaAragonite
  Omega aragonite, aragonite saturation state
• OmegaCalcite
  Omega calcite, calcite saturation state

encoding

latin1

Details

This function assumes that the simplified synthetic sea water recipe described by Dickson et al. (2007) was used. It is the basis of the synthetic seawater that has been used to determine a variety of equilibrium constants for use in sea water. Note that this function does not account for the effect of the changes in the calcium concentration of the dissociation constants of carbonic acid and on the solubility product of CaCO3 (Ben-Yaakov and Goldhaber, 1973). Pressure corrections and pH scale: For K1, K2, pK1, pK2, pK3, Kw, Kb, Khs and Ksi, the pressure correction was applied on the seawater scale. Hence, values were first transformed from the total scale to the seawater scale, the pressure correction applied as described by Millero (1995), and the value was transformed back to the required scale (T, F or SWS). For Kf, the pressure correction was applied on the free scale. The formulation of Dickson and Riley (1979) provides Kf on the free scale but that of Perez and Fraga (1987) provides it on the total scale. Hence, in that case, Kf was first transformed from the total scale to the free scale. With both formulations, the pressure correction was applied as described by Millero (1995), and the value was transformed back to the required scale (T, F or SWS). For Ks, the pressure correction was applied on the free scale. The pressure correction was applied as described by Millero (1995), and the value was transformed back to the required scale (T, F or SWS). For Kn, The pressure correction was applied on the seawater scale. The pressure correction was applied as described by Millero (1995), and the value was transformed back to the required scale (T, F or SWS).

References

Ben-Yaakov S. and Goldhaber M. B., 1973 The influence of sea water composition on the apparent constants of the carbonate system. Deep-Sea Research 20, 87-99. Dickson A. G., Sabine C. L. and Christian J. R., 2007 Guide to best practices for ocean CO2 measurements. PICES Special Publication 3, 1-191. Gattuso J.-P. and Lavigne H, 2009. Perturbation experiments to investigate the impact of ocean acidification: approaches and software tools. Biogeosciences 6, 4413-4439. Millero F. J., 1995. Thermodynamics of the carbon dioxide system in the oceans. Geochimica Cosmochimica Acta 59: 661-677.

Examples

pCa(flag=15, var1=2302e-6, var2=2050e-6, Ca=0.01028, S=35, T=20, P=0, 
	Pt=0, Sit=0, pHscale="T", kf="pf", k1k2="l") # with normal Ca concentration
pCa(flag=15, var1=2302e-6, var2=2050e-6, Ca=0.01028/2, S=35, T=20, P=0, 
	Pt=0, Sit=0, pHscale="T", kf="pf", k1k2="l") # with 0.5 * Ca concentration