Ombrotrophic vs. Minerotrophic
The primary axis used to classify peatlands: what water feeds them, and therefore how acidic and mineral-rich the resulting peat is.
The Two States
| Ombrotrophic | Minerotrophic | |
|---|---|---|
| Water source | Rainfall only | Groundwater / surface water |
| pH | 3.3–4.5 (strongly acidic) | 4.5–7.0 |
| Mineral content | Low | Higher |
| Dominant vegetation | Sphagnum moss | Sedges, reeds, grasses |
| Mire type | Raised bog, blanket bog | Fen |
| Typical cosmetic peat role | Baltic/Nordic humic-acid-driven products | Central European mineral-forward Moortherapie |
“Ombrotrophic” comes from Greek ombros (rain) + trophe (nourishment); “minerotrophic” reflects nourishment by mineral-bearing water.
Why the Distinction Drives Peat Composition
Because groundwater carries dissolved minerals and buffers acidity, a minerotrophic system supports different plant communities (sedges over sphagnum) and different decomposition chemistry. This is the root cause of the compositional split seen across the graph: ombrotrophic (bog) peat trends toward high humic/fulvic acid concentration with low minerals; minerotrophic (fen) peat trends toward higher trace mineral content — notably iron — with comparatively lower humic acid concentration. A peat deposit’s position on this axis is one of the first things a geological survey establishes, alongside its degree of humification.