The nutrient load in flooding waters depends on the flux volume of water and its concentration (source). Thus, ombrotrophic bogs are nutrient-poor because the source is rainwater, whereas the water supply to minerotrophic bogs is often rich in minerals, depending on the substrate. This influences not only the loading of nutrients to the wetland but often the acidity. Waters with low dissolved solids tend to become acid in contact with peats, whereas mineral-rich waters are much less acid, especially if they percolae over a calcium carbonate rock.  Saline waters are highly buffered and even in reducing sediment seldom are much below pH 7.