TABLE 4.
Percentages of isotopic labeling of OTUs in winter samplesa with [15N]urea or [13C]bicarbonate
| Domain | Division/class | Family/genus | % labelingb with: |
|
|---|---|---|---|---|
| 15N | 13C | |||
| Bacteria | Proteobacteria | Unclassified | 35 | 18 |
| Alphaproteobacteria | SAR11 (Surface 1) | 30 | 14 | |
| Archaea | Crenarchaeota | Marine group I | 27 | 27 |
| Bacteria | Gammaproteobacteria | Oceanospirillales | 39 | 12 |
| Alphaproteobacteria | SAR11 (Surface 2) | 31 | 22 | |
| Verrucomicrobia | Verrucomicrobiaceae | 13 | 3 | |
| Alphaproteobacteria | Rhodobacteraceae | 19 | 15 | |
| Gammaproteobacteria | Alteromonadaceae | 28 | 17 | |
| Deltaproteobacteria | SAR324 (marine group B) | 49 | 13 | |
| Alphaproteobacteria | SAR11 (Chesapeake Delaware Bay) | 32 | 17 | |
| Verrucomicrobia | Verrucomicrobiaceae | 13 | 6 | |
| Deltaproteobacteria | Nitrospinaceae | 16 | 9 | |
| Alphaproteobacteria | Rhodobacteraceae | 13 | 7 | |
| Bacteroidetes | Cryomorphaceae | 42 | −9 | |
| Alphaproteobacteria | SAR11 (Surface 4) | 32 | 16 | |
| Alphaproteobacteria | SAR11 (Deep 1) | 37 | 14 | |
| Alphaproteobacteria | Rhodospirillaceae | 29 | 20 | |
| Actinobacteria | Acidimicrobiales (SVA0996) | 32 | 5 | |
a
Only OTUs that accounted for more than 0.5% of reads across libraries from gradient fractions are shown. OTUs are shown in rank order, with the first being the most abundant.
b
Percentages were calculated from 16S rRNA gene OTU frequencies in Illumina libraries with respect to densities of fractions. Percentages in boldface are at or above the 30% and 15% thresholds used as indicators that uptake of 15N- and 13C-labeled substrates occurred, respectively.