PPT Slide
Characteristics of subsurface ecosystems on Earth.
- Absence of phototrophy. But products of phototrophy may act as electron-donors and carbon-sources for subsurface ecosystems.
- Generally limitation of electron donors and nutrients (mineral dissolution) resulting in extremely low activity
- Electron-donors may be soil organic carbon, reduced redox species (lithotrophy) or geochemical sources (H2)
- Mostly anaerobic: iron-reducing, sulfate-reducing, methanogenic
- Low activity may change to high activity when reactive carbon sources are added externally