Posted: Tue Jan 10, 2012 3:49 pm
Kouta:
Old tropical rainforests can have mechanisms and plant species adaptations that allow them to retain and very tightly recycle nutrients, and losses to the ecosystem may be so small that atmospheric inputs can replace them, even for P (see page 512 of the article). This would allow retrogressed tropical rainforests such as in the Amazon and Australia to maintain high biomass, possibly for millions of years. However, as the paper states, clearing might push them past the maximal biomass state.
In the Pacific Northwest soils are still quite young, and ecosystem acidification, (a type of retrogression that occurs in colder climates where Sphagnum moss takes over, and over thousands of years acidifies the soil, water and entire ecosystem, forming peatlands, moors, and bogs) has not affected the vast majority of the landscape yet. It probably won't retrogress for many thousands more years, if ever, because there is substantial input of nutrients from windborn cations from the ocean, and from volcanic ash (the latter affects most areas every several hundred to a few thousand years).
Lee
Old tropical rainforests can have mechanisms and plant species adaptations that allow them to retain and very tightly recycle nutrients, and losses to the ecosystem may be so small that atmospheric inputs can replace them, even for P (see page 512 of the article). This would allow retrogressed tropical rainforests such as in the Amazon and Australia to maintain high biomass, possibly for millions of years. However, as the paper states, clearing might push them past the maximal biomass state.
In the Pacific Northwest soils are still quite young, and ecosystem acidification, (a type of retrogression that occurs in colder climates where Sphagnum moss takes over, and over thousands of years acidifies the soil, water and entire ecosystem, forming peatlands, moors, and bogs) has not affected the vast majority of the landscape yet. It probably won't retrogress for many thousands more years, if ever, because there is substantial input of nutrients from windborn cations from the ocean, and from volcanic ash (the latter affects most areas every several hundred to a few thousand years).
Lee