Table 1 Parameter values of the regression lines ([x] = a[CO₂] + b), the coefficients of determination (R²) between CO₂ concentration and the concentration of the other substances measured, as well as the ratio of their standard deviations

20–23 Jan

 a [nmol µmol⁻¹]

13.83 ± 0.33

25.59 ± 0.36

0.31 ± 0.01

 b [nmol]

− 3821 ± 140

− 10,465 ± 155

202 ± 6

 R²

0.978

0.984

0.864

 SD_x/SD_CO2

14.13

25.79

0.33

26–31 Jan

 a [nmol µmol⁻¹]

6.69 ± 0.24

25.79 ± 0.59

0.15 ± 0.01

 b [nmol]

− 797 ± 105

− 10,563 ± 253

269 ± 3

 R²

0.853

0.937

0.773

 SD_x/SD_CO2

7.25

26.64

0.17

11–17 Feb

 a [nmol µmol⁻¹]

7.95 ± 0.21

14.96 ± 0.34

0.31 ± 0.01

 b [nmol]

− 1333 ± 89

− 6000 ± 143

201 ± 3

 R²

0.897

0.923

0.940

 SD_x/SD_CO2

8.39

15.57

0.32