Table 2. Regression analyses of 13C over 15N uptake for the functional groups heterocystous cyanobacteria (Aphanizomenon sp., Dolichospermum sp., Nodularia sp.), associated bacteria (Alphaproteo and Cytophaga/Bacteroidetes bacteria), and non-heterocystous cyanobacteria (Pseudanabaena sp.) for the different incubation times.
| Incubation time | 10 min | 30 min | 60 min | 6 h | 24 h |
|---|---|---|---|---|---|
| Heterocystous cyanobacteria | Y = 0.001+0.246x, R2 = 0.88, p = 0.000 |
Y = 0.004–0.024x, R2 = 0.00, p = 0.308 |
Y = 0.001+0.03x, R2 = 0.16, p = 0.000 |
Y = 0.002+0.149x, R2 = 0.82, p = 0.000 |
Y = 0.00+0.01x, R2 = 0.56, p = 0.000 |
| Associated bacteria | Y = 0.004+0.018x, R2 = 0.02, p = 0.471 |
Y = 0.003+0.105x, R2 = 0.45, p = 0.06 |
Y = -0.02+1.94x, R2 = 0.52, p = 0.000 |
Y = 0.004+0.329x, R2 = 0.4, p = 0.007 |
Y = 0.015–0.022x, R2 = 0.24, p = 0.02 |
| Non-heterocystous cyanobacteria | Y = 0.004+0.028x, R2 = 0.04, p = 0.169 |
Y = 0.003+0.105x, R2 = 0.28, p = 0.02 |
Y = 0.004+0.05x, R2 = 0.72, p = 0.001 |
Y = 0.003+0.117x, R2 = 0.82, p = 0.000 |
Y = 0.009–0.002x, R2 = 0.02, p = 0.27 |
| Anova | F = 2.77, p = 0.066 | F = 5.69, p = 0.001 | F = 12.9, p = 0.000 | F = 60.42, p = 0.000 | F = 9.79, p = 0.000 |
Anova results display comparisons of regression slopes of the different functional groups (ANCOVAs with and without interactions between the factor (functional group) and the co-variable (15N uptake) were calculated with linear models, with 13C uptake set as dependent variable. ANOVAs were then calculated between both ANCOVAs to test for differences in the regression slopes).