Table 2 Effects of seawater CO2 enrichment and calcite deposit on the silt’s average (± 1 SD) O2 consumption, porewater oxygenation, and H+ flux.

From: Biogeochemical feedbacks to ocean acidification in a cohesive photosynthetic sediment

 

Control (+Sand)

+Calcite

pH 8.0

pH 7.6

d ES

CI

pH 8.0

pH 7.6

d ES

CI

Light

(6)

(6)

  

(6)

(6)

  

O2-pd

8.5 ± 0.2

8.2 ± 0.7

0.56

0.28/0.83

9.0 ± 0.4

8.4 ± 0.4

1.56

1.36/1.75

DOE

489 ± 442

382 ± 277

0.32

− 190/191

478 ± 342

490 ± 337

− 0.04

− 175/175

RA

332 ± 247

315 ± 290

0.07

− 143/143

302 ± 198

377 ± 333

− 0.30

− 142/141

 

(5)

(5)

  

(5)

(6)

  

H+ fluxDBL

− 217 ± 55

− 437 ± 220

1.53

− 87.3/90.4

− 156 ± 92

− 421 ± 140

2.41

− 62.5/67.3

H+ fluxsub

96 ± 16

42 ± 19

3.42

− 6.4/13.2

121 ± 17

84 ± 3

3.51

− 2.78/9.79

Darkness

(6)

(5)

  

(6)

(6)

  

O2-pd

7.6 ± 0.5

7.0 ± 0.7

1.32

1.04/1.60

7.8 ± 0.6

7.3 ± 0.6

0.97

0.66/1.28

DOE

− 263 ± 52

− 293 ± 55

0.60

− 28.0/29.2

− 178 ± 64

− 239 ± 33

1.31

− 25.1/27.7

RA

− 229 ± 14

− 254 ± 53

0.73

− 19.0/20.4

− 219 ± 38

− 235 ± 36

0.47

− 18.5/19.4

RV

− 30 ± 2.2

− 37 ± 9.6

1.20

− 2.32/4.72

− 28 ± 7.0

− 32 ± 6.9

0.65

− 2.93/4.23

 

(4)

(4)

  

(6)

(6)

  

H+ fluxDBL

87 ± 46

152 ± 92

− 0.97

− 47.0/45.0

106 ± 90

− 155 ± 111

2.83

− 49.4/55.1

H+ fluxsub

55 ± 21

41 ± 12

0.94

− 9.2/11.1

84 ± 20

95 ± 33

− 0.44

− 14.6/13.7

  1. O2-pd, O2 penetration depth (mm); DOE, diffusive O2 exchange (μmol m−2 h−1); RA, depth-integrated O2 production (μmol m−2 h−1); RV, integrated volume-specific O2 production (= RA/O2-pd, nmol cm−3 h−1). H+ fluxDBL and H+ fluxsub (mmol m−2 h−1), diffusive H+ flux calculated from the vertical [H+] gradients in the diffusive boundary layer and at the bottom 2 mm of the oxic layer, respectively. Negative and positive DOE, R or H+ flux values indicate sediment solute uptake and release, respectively. The d Effect size (d ES) and 95% confidence intervals (CI) refer to pH 8.0 (ambient) versus pH 7.6 (CO2-enriched) comparisons. Numbers in parenthesis are number of replicate measurements (cores).
Back to article page