Table 2 Seawater carbonate chemistry parameters (i.e. pH_T, A_T, pCO₂, HCO₃⁻, CO₃²⁻, CO₂), salinity and nutrient concentrations (i.e. NO₃⁻, Si, NH₄⁺, PO₄³⁻) at the start of each experimental trial (I–II).

pH_T

7.72 ± 0.003

7.73 ± 0.010

7.78 ± 0.006

7.49 ± 0.04

7.46 ± 0.007

7.54 ± 0.001

7.80 ± 0.0007

7.77 ± 0.03

7.88 ± 0.014

7.46 ± 0.008

7.47 ± 0.031

7.55 ± 0.006

Salinity (psu)

30.7

30.8

30.8

30.7

30.5

30.6

29.5

29.5

29.5

29.5

29.5

29.5

A_T (µmol kg⁻¹)

2216

2208 ± 8.46

2218 ± 0.30

2215 ± 2.33

2195 ± 10.30

2186 ± 16.57

2126 ± 2.29

2153 ± 1.61

2120 ± 7.00

2155 ± 30.90

2166 ± 3.15

2167 ± 4.99

pCO₂ (µatm)

926.28

902 ± 7.64

785 ± 15.76

1587 ± 221.71

1727 ± 24.79

1442 ± 11.08

726 ± 2.21

791 ± 64.24

583 ± 19.93

1732 ± 61.12

1689 ± 3.16

1414 ± 18.83

HCO₃⁻ (µmol/kg)

1967.72

1955 ± 7.64

1934 ± 4.17

2011 ± 78.76

2049 ± 7.29

2018 ± 15.50

1849 ± 2.61

1888 ± 18.09

1795 ± 2.87

2017 ± 31.77

2024 ± 8.39

1998 ± 2.41

CO₃²⁻ (µmol/kg)

102.45

104.17 ± 0.40

117.13 ± 1.84

63.01 ± 3.89

59.82 ± 1.28

69.42 ± 0.53

113.47 ± 0.02

108.86 ± 6.75

133.24 ± 4.12

56.63 ± 0.21

58.50 ± 2.13

68.08 ± 1.09

CO₂ (µmol/kg))

26.92

26.14 ± 0.10

22.76 ± 0.45

45.99 ± 6.42

50.04 ± 0.71

41.78 ± 0.32

21.16 ± 0.06

23.06 ± 1.87

16.99 ± 0.58

50.45 ± 1.78

49.20 ± 2.20

41.18 0.54

NO₃ (µM)

3.01 ± 0.22

5.13 ± 0.16

3.03 ± 0.97

3.50 ± 2.66

4.48 ± 1.37

3.05 ± 0.33

13.60 ± 0.10

12.86 ± 0.04

13.20 ± 0.03

13.12 ± 0.01

13.18 ± 0.64

13.06 ± 

Si (µM)

9.82 ± 0.30

8.44 ± 0.55

6.49 ± 4.16

9.13 ± 2.99

8.26 ± 0.42

4.76 ± 0.12

10.91 ± 0.12

12.71 ± 1.58

11.25 ± 0.36

11.08 ± 0.97

10.82 ± 0.49

11.98 ± 2.00

PO₄³⁻ (µM)

0.50 ± 0.02

0.06 ± 0.06

0.25 ± 0.007

0.59 ± 0.18

0.58 ± 0.12

0.45 ± 0.02

1.12 ± 0.09

1.27 ± 0.01

1.12 ± 0.12

1.11 ± 0.02

1.09 ± 0.11

1.06 ± 0.05