Table 1. Comparison of Marker 113 and seawater chemistry characteristics.
| Fluid Characteristic | Marker 113 | Seawater |
|---|---|---|
| Temperature, °C | 24.1 | 2.4 |
| Percent seawater | 96 | 100 |
| Magnesium, mmol kg−1 | 49.1 | 51.5 |
| Total CO2, mmol kg−1 | 4.6 | 2.3 |
| Hydrogen sulfide, mmol l−1 | 0.6 | 0.0 |
| Ammonia, μmol l−1 | 3.5 | <0.6 |
| Silica, μmol l−1 | 636 | 155 |
| pH | 6.2 | 7.8 |
| Hydrogen, μmol kg−1 | <1.0 | 0.0 |
| Methane, μmol kg−1 | 13.2 | 0.0 |
| Oxygen, μmol l−1 | 7.0 | 28.3 |
| Microbial cells per ml | 4.4 × 105 | 1.8 × 104 |
| Virus-like particles per ml | 1.6 × 108 | ND |
Abbreviation: ND, no data.
Percent seawater was calculated via the conservative tracer magnesium (Mg): [Mg]vent/[Mg]seawater × 100. Most seawater data are reported from Akerman et al. (2013). Seawater magnesium and total CO2 were measured from a 2013 sample, whereas oxygen data were reported from a 2015 CTD cast at 1520 m.