TABLE 3.
Percentages of isotopic labeling with 15N or 13Ca derived from SIP gradients
| Domain | Division/class | Substrate | % incorporationb |
|---|---|---|---|
| Archaea | Crenarchaeota | [15N]urea | 31 |
| Bacteria | Actinobacteria | [15N]urea | 17 |
| Bacteroidetes | [15N]urea | 22 | |
| Firmicutes | [15N]urea | 31 | |
| Planctomycetes | [15N]urea | 22 | |
| Verrucomicrobia | [15N]urea | 12 | |
| Alphaproteobacteria | [15N]urea | 20 | |
| Betaproteobacteria | [15N]urea | 33 | |
| Deltaproteobacteria | [15N]urea | 25 | |
| Gammaproteobacteria | [15N]urea | 23 | |
| Archaea | Crenarchaeota | [13C]bicarbonate | 22 |
| Bacteria | Actinobacteria | [13C]bicarbonate | 14 |
| Bacteroidetes | [13C]bicarbonate | 12 | |
| Firmicutes | [13C]bicarbonate | 17 | |
| Planctomycetes | [13C]bicarbonate | 14 | |
| Verrucomicrobia | [13C]bicarbonate | 12 | |
| Alphaproteobacteria | [13C]bicarbonate | 18 | |
| Betaproteobacteria | [13C]bicarbonate | 15 | |
| Deltaproteobacteria | [13C]bicarbonate | 18 | |
| Gammaproteobacteria | [13C]bicarbonate | 15 |
a
Percentages were calculated from 16S rRNA gene frequency data with respect to densities of fractions.
b
Percentages in boldface are at or above the 30% and 15% thresholds used as indicators that uptake of 15N- and 13C-labeled substrates had occurred, respectively.