TABLE 1.
Nod gene and 16S rRNA gene sequence abundance in DNA extracted from various environmental sites.a
| Site description | Nod copies/g soil | 16S rRNA copies/g soil | Relative abundance | Nitrogen | Reference |
|---|---|---|---|---|---|
| Variably saturated environmental samples | |||||
| Freshwater riverbank sediments | 7.7 × 104 | 1.9 × 109 | 0.004% | 1.4 mg/l NO3-Nb | This study |
| Freshwater creek sediments | 1.4 × 106 | 1.5 × 1010 | 0.01% | ||
| Freshwater creek Site 2 sediments | 3.0 × 106 | 1.6 × 1010 | 0.016% | ||
| Farm drainage ditch soil | 1.9 × 106 | 7.6 × 109 | 0.025% | ||
| Farm tile drain soil | 4.3 × 106 | 9.7 × 109 | 0.045% | 1.8 mg/l NO3-Nb | |
| Farm bog soil | 4.5 × 106 | 8.4 × 109 | 0.054% | ||
| Farm grass waterway soil core | 2.5 × 104 – 2.3 × 106 | 2.5 × 107 – 1.0 × 1010 | 0.004% – 0.1% | ||
| BTEX-impacted aquifer sediments | 1.6 × 107 | 1 × 109 | 2% | – | (1) |
| Alpine wetland soils | 2.4 × 105 | – | – | 0.0195 mg/l NO3-N | (2) |
| Mangrove sediments | 7.7 × 107 | – | – | 0.44 mg/kg NO3-N | (3) |
| Hydrocarbon contaminated environment | 1.8 × 107 | – | – | 4.74 mg/kg NO3-N | |
| Agricultural soil | 1.5 × 107 | 1.4 × 109 | 1.1% | 1.8 g/kg TN | (4) |
| Agricultural soil with fertilizer | 1 × 107 | 9.8 × 108 | 1.0% | 1.9 g/kg TN | |
| Agricultural soil with fertilizer and straw | 1.3 × 107 | 1.1 × 109 | 1.2% | 2.6 g/kg TN | |
| Agricultural soil with fertilizer and manure | 1.5 × 107 | 1.2 × 109 | 1.3% | 2.2 g/kg TN | |
| Saturated environmental samples | |||||
| Farm grass waterway soil core | 2.7 × 105 – 1. ×106 | 2.3 × 107 – 9. ×107 | 1.2% | This study | |
| BTEX-impacted aquifer well sludge | 5 × 108 | 1 × 1011 | 2% | 2 mg/l NO3 | (1) |
| BTEX-impacted aquifer sludge | 8.3 × 102c | – | – | (5) | |
| Lake sediment (meso-oligotrophic) | 3.2 × 107 | 1 × 109 | 3.2% | 0.2 mg/l TN | (4) |
| Lake sediment (eutrophic) | 1.5 × 107 | 2 × 109 | 0.8% | 0.5 mg/l TN | |
| Lake sediment (dystrophic) | 2.2 × 106 | 4 × 108 | 0.6% | 1 mg/l TN | |
| Lake sediment (dystrophic) | 3 × 106 | 3 × 108 | 1.0% | 1.7 mg/l TN | |
a
Gene abundances were normalized to soil wet weight. Where available, the amount of nitrogen present (as nitrate-nitrogen [NO3-N] or total nitrogen [TN]) is displayed.
b
Nitrogen data retrieved from Iowa Water Quality Information System (IWQIS) sensor located in water.
c
Primer set nod840F/nod1012R used to obtain this value in the referenced study.