|
factor ß method Þ |
LiCOR Infra-red |
GC (TCD detector) |
pH electrode |
Spectropho-tometric pH |
14 C radio--activity |
|
Cost |
High |
Medium |
Low |
Medium |
Low? |
|
Already available at UEA |
No |
Yes |
Yes |
No |
Yes |
|
Ease of use |
Easy |
Medium |
Easy (but not to calibrate) |
Difficult to set up |
Easy but safety and disposal problems |
|
Continuous monitoring by computer possible? |
Yes -easy |
No. Have to keep samples |
Yes, but time-lag |
Possible but even more difficult. |
Yes |
|
Reliable and Consistent? |
Yes |
Yes? |
Poor |
Yes? |
Yes |
|
Accuracy |
Good |
Poor (FID detector OK) |
Medium -if well calibrated |
Good |
Good? |
|
pCO2 determination depends on alkalinity and equilibrium coefficients? |
No |
No |
Yes |
Yes |
Yes |
|
Needs equilibrator for water pCO2? |
Yes |
Yes |
No |
No |
No |
|
Needs extra gas phase measurement |
n.a. |
n.a. |
Yes |
Yes |
No: assume zero |
|
Can measure influx and eflux transfer velocities |
Yes |
Yes |
Yes |
Yes |
No unless very leaktight |
|
Reliable at sea |
Yes |
Yes? |
Poor |
Yes |
Can't use it |