Table 1. Summary of seawater carbonate chemistry.
Carbonate parameters (n = 6, ±SE) were calculated from total alkalinity (AT, n = 6) and pH (n = 6) measurements of seawater corresponding to each treatment. (+) and (–) refers to % increase and decrease, respectively, in carbonate chemistry parameters after 4.4h incubation under 18 μmol photons m-2 s-1.
| Treatment | Cycle | Target pH | EXPM pH | H+ × 10−3 μmol kg-1 | pCO2 μatm | AT μmol kg-1 | DIC μmol kg-1 | H2CO3 μmol kg-1 | μmol kg-1 | μmol kg-1 | ΩA | ΩC |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Static pH 8.05 | Night | 8.05 | 8.05 (0.001) | 9.00 (0.031) | 430 (2) | 2484 (11) | 2285 (0.866) | 19.32 (0.093) | 2117 (1.313) | 149 (0.536) | 2.26 (0.008) | 3.56 (0.013) |
| Day | 8.05 | 8.05 (0.004) | 8.90 (0.084) | 425 (6) | 2484 (11) | 2283 (2.381) | 19.09 (0.250) | 2114 (3.618) | 151 (1.476) | 2.29 (0.022) | 3.59 (0.035) | |
| After 4.4h light incubation | 8.09 (0.037) | 8.08 (0.659) | 356 (44) | 2278 (55) | 2068 (60.739) | 15.98 (1.982) | 1902 (64.372) | 151 (13.295) | 2.29 (0.202) | 3.59 (0.317) | ||
| % change | (+) 0.52 | (-) 9.23 | (-) 16.26 | (-) 8.26 | (-) 9.42 | (-) 16.30 | (-) 10.04 | (+) 0.09 | (+) 0.09 | (+) 0.09 | ||
| Fluctuating, mean daily pH = 8.05 | Night | 7.65 | 7.65 (0.005) | 22.48 (0.233) | 1180 (16) | 2484 (11) | 2439 (1.817) | 52.11 (0.687) | 2323 (1.921) | 66 (0.783) | 0.99 (0.012) | 1.56 (0.019) |
| Day | 8.45 | 8.41 (0.003) | 3.92 (0.028) | 158 (2) | 2484 (11) | 2073 (2.664) | 7.11 (0.079) | 1779 (4.382) | 288 (1.792) | 4.37 (0.027) | 6.85 (0.043) | |
| After 4.4h light incubation | 8.34 (0.024) | 4.61 (0.269) | 183 (15) | 2339 (12) | 1990 (8.977) | 8.25 (0.687) | 1741 (20.598) | 241 (12.969) | 3.65 (0.197) | 5.74 (0.309) | ||
| % change | (-) 0.83 | (+) 17.52 | (+) 16.24 | (-) 5.84 | (-) 4.02 | (+) 16.09 | (-) 2.11 | (-) 13.30 | (-) 13.30 | (-) 13.30 | ||
| Static pH 7.65 | Night | 7.65 | 7.65 (0.002) | 22.39 (0.094) | 1174 (6) | 2484 (11) | 2438 (0.731) | 51.88 (0.276) | 2322 (0.774) | 66 (0.315) | 1.00 (0.005) | 1.57 (0.008) |
| Day | 7.65 | 7.65 (0.001) | 22.34 (0.039) | 1172 (3) | 2484 (11) | 2438 (0.307) | 51.78 (0.116) | 2322 (0.325) | 66 (0.132) | 1.00 (0.002) | 1.57 (0.003) | |
| After 4.4h light incubation | 7.80 (0.029) | 15.71 (1.110) | 741 (68) | 2271 (16) | 2177 (18.110) | 32.96 (2.978) | 2061 (19.338) | 84 (6.118) | 1.28 (0.093) | 2.00 (0.146) | ||
| % change | (+) 2.00 | (-) 29.71 | (-) 36.78 | (-) 8.56 | (-) 10.71 | (-) 36.35 | (-) 11.24 | (+) 27.47 | (+) 27.47 | (+) 27.47 | ||
| Fluctuating, mean daily pH = 7.65 | Night | 7.25 | 7.23 (0.002) | 59.03 (0.325) | 3227 (26) | 2484 (11) | 2584 (1.383) | 139.13 (1.090) | 2420 (0.482) | 26 (0.196) | 0.39 (0.003) | 0.62 (0.005) |
| Day | 8.05 | 8.05 (0.004) | 8.88 (0.078) | 424 (6) | 2484 (11) | 2282 (2.554) | 19.04 (0.268) | 2113 (3.881) | 151 (1.584) | 2.29 (0.024) | 3.60 (0.038) | |
| After 4.4h light incubation | 8.02 (0.036) | 9.62 (0.821) | 435 (62) | 2279 (21) | 2102 (37.684) | 19.48 (2.748) | 1954 (46.144) | 130 (12.361) | 1.98 (0.187) | 3.10 (0.294) | ||
| % change | (-) 0.43 | (+) 8.27 | (+) 2.49 | (-) 8.25 | (-) 7.89 | (+) 2.26 | (-) 7.56 | (-) 13.72 | (-) 13.72 | (-) 13.72 |