and
>That's a good question. I think the reason bogs and seeps have so few
>trace elements is due to the long, slow action of the water leeching
>out the minerals. These bogs and swampy areas have had all the
>minerals washed out by repeated and prolonged flooding. Even a bog
>that seems to be land locked (for lack of a better term) may be
>repeatedly flooded during the wet season. The soils left are just very
>poor.
My understanding is that there are two reasons bog water is so low in
nutrients. The first is that as another esteemed member noted, the pH in the
water is very low so the nutrient compounds, which are positive ions, are
unavailable. This is why fertilizers designed for use in acid soils are
different from other fertilizers (i.e. Miracid). Second, many true bogs are
in the condition of having a "perched water table." This means the local
water table is much higher than the actual water table. All the available
water does not come from the surrounding terrain, but rather from straight
overhead, i.e. rain. There is little opportunity for nutrient-laden water to
enter. This is of course different from riparian CP habitats. Those who are
interested further in these matters are directed towards my fave bog-water
book, A Focus on Peatlands and Peat Mosses, by Crum.
BAMR