Table 2.
Most-probable number (MPN, L-1) estimates of heterotrophs, H2-producing heterotrophs, methanogens, and non-methanogenic hydrogenotrophs that grow at 55°C and 80°C.
| 80°C |
55°C |
|||||||
|---|---|---|---|---|---|---|---|---|
| 2012 | 2013 | 2014 | 2015 | 2012 | 2013 | 2014 | 2015 | |
| Marker 113 | ||||||||
| Heterotrophs | 2,790 | >33,000 | >33,000 | 1,140 | NDa | >33,000 | >33,000 | 1,140 |
| H2-prod. heterotrophs | 220 | 330 | 33,000 | ND | ND | 120 | 2,250 | 276 |
| Methanogens | 120 | 1,050 | 6,300 | 1,140 | ND | 330 | 13,800 | 33,000 |
| Other autotrophs | 102 | 5,220 | ND | ND | 270 | 5,610 | 1,350 | ND |
| Initial total cells (×108, L-1)b | 3.4 | 5.4 | 8.5 | 15.0 | ||||
| Marker 33 | ||||||||
| Heterotrophs | – | >33,000 | >33,000 | 33,000 | – | >33,000 | >33,000 | 1,290 |
| H2-prod. heterotrophs | – | 7,200 | 4,500 | ND | – | ND | 840 | 108 |
| Methanogens | – | 13,800 | 13,800 | 1,290 | – | 330 | 2,790 | ND |
| Other autotrophs | – | ND | ND | 33,000 | – | 32,310 | 4,224 | 13,800 |
| Initial total cells (×108, L-1) | – | 2.8 | 9.6 | 8.1 | ||||
| Anemone (ASHES) | ||||||||
| Heterotrophs | 7,200 | 13,800 | >33,000 | >33,000 | 690 | 7,200 | >33,000 | 13,800 |
| H2-prod. heterotrophs | 2,790 | 1,290 | 1,290 | 120 | ND | ND | 13,800 | 450 |
| Methanogens | ND | 276 | 1,290 | 1,290 | ND | 690 | 120 | 450 |
| Other autotrophs | 276 | 1,170 | 2,340 | 13,680 | 270 | 2,670 | 4,500 | 4,380 |
| Initial total cells (×108, L-1) | 0.8 | 4.1 | 9.4 | 10.0 | ||||
aND, not detected. bTotal cell concentration is for the hydrothermal fluid sample prior to incubation.