Figure 5C

ΔTCO2  =  change in TCO2 concentration due to equilibration
ΔCO2  =  volume of CO2 exchanged between water and headspace
Cmeas  =  mole fraction of CO2 in equilibrated air
Vfill  =  volume of headspace created by displacing water in equilibrator
Vthis  =  volume of tubing & pump not swept while creating headspace
Vother  =  volume of tubing connecting equilibrator to 6-port valve (filled with air from "other" equilibrator)
Vrepl  =  volume of tubing connecting 6-port and 10-port valves & sample loop (air "replaced" with calibration gas before each analysis)
Cfill  =  mole fraction of CO2 in air used to create headspace
Cthis  =  mole fraction of CO2 in residual air in tubing & pump
Cother  =  mole fraction of CO2 in preceeding sample in "other" equilibrator
Crepl  =  mole fraction of CO2 in "replacement" air
MolarVolCO2  =  molar volume of CO2 at temperature of equilibration
VolH2O  =  volume of water sample in equilibrator
DensityH2O  =  density of water sample at temperature of equilibrator
TCO2(end)  =  concentration of TCO2 in sample after equilibrating with headspace
TCO2(meas)  =  concentration of TCO2 measured colulometrically in fresh sample
pCO2(end)  =  partial pressure of CO2 measured after equilibration
PressureEq  =  pressure of equilibration (in atmospheres)
TALK  =  total alkalinity of sample (unchanged during equilibration)
pCO2(initial)  =  partial pressure of CO2 of sample water PRIOR TO equilibration (at temperature of equilibration)

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