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We determined the rate elements are sequestered in hummock peat of an ombrotrophic bog. The peat below 65 cm was radiocarbon dated and the upper 65 cm was dated using the acid insoluble ash (AIA) content and Polytrichum strictum growth increments. Peat produced during the last 9 yrs contains roughly all the N, P, Ca, and Mg, and about twice the K, deposited during this period. However, these nutrients are depleted from older peat at rates that depends on mineralization and adsorption properties of the ions. Changes in inorganic chemistry occur mostly while peat is in the acrotelm. Therefore, only peat in the catotelm will show the true accumulation rate of elements. In peat below 65 cm, the annual accumulation rate, as a percent of the present annual input, is: N-38, K-2.5, P-18, Na-1.5, Ca-3, Mg-51 and S-3.5%. Dust fall increased 4-fold about 500 yrs ago and has remained at this level. Therefore, the annual accumulation of elements in peat below 65 cm, or older than 522 yrs, presumably underestimates present accumulation in the catotelm of soil-derived elements, especially Ca and P, and elements that have increased due to pollution such as N and S. This increased dust fall probably changed the floristic composition of the vegetation as well as production and decay.
Keywords: Accumulation, dating, element retention, input changes, nutrient dynamics
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Damman,
Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Road, Storrs, CT 06269-3042, USA
Sähköposti:
ei.tietoa@nn.oo
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Tolonen,
Sähköposti:
ei.tietoa@nn.oo
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Sallantaus,
Sähköposti:
ei.tietoa@nn.oo
