Table 3 Linear mixed effect models for all nitrogen uptake and metabolism variables.

From: Nitrate fertilisation does not enhance CO2 responses in two tropical seagrass species

Parameter

Source

Halodule uninervis

Thalassia hemprichii

df

F

p

df

F

p

Nitrate uptake

pCO2

1

0.157

0.698

1

1.014

0.331

Nitrate

1

0.000

0.984

1

0.156

0.698

pCO2 ×Nitrate

1

0.380

0.548

1

7.392

0.017

Nitrate reductase

pCO2

1

3.076

0.101

1

1.144

0.303

Nitrate

1

2.523

0.135

1

8.092

0.013

pCO2 ×Nitrate

1

0.526

0.480

1

4.061

0.064

Glutamine synthetase

pCO2

1

0.142

0.712

1

0.089

0.769

Nitrate

1

0.376

0.550

1

0.289

0.600

pCO2 ×Nitrate

1

3.443

0.085

1

0.466

0.506

Carbon content

pCO2

1

1.420

0.253

1

0.928

0.352

Nitrate

1

1.390

0.259

1

0.094

0.764

pCO2 ×Nitrate

1

0.330

0.576

1

0.094

0.764

Nitrogen content

pCO2

1

0.310

0.584

1

2.180

0.162

Nitrate

1

1.350

0.266

1

4.363

0.056

pCO2 ×Nitrate

1

0.510

0.487

1

3.113

0.099

C:N ratio

pCO2

1

1.571

0.231

1

1.436

0.251

Nitrate

1

3.227

0.094

1

4.846

0.045

pCO2 ×Nitrate

1

0.282

0.604

1

3.258

0.093

  1. Variables were analysed with pCO2 as a continuous predictor and nitrate as a categorical factor. Individual aquaria were included as replicates (N = 3), with two sub-replicate pots nested within aquaria. P-values < 0.05 are in bold.
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