TITLE	Nutrient dynamics of two aquatic angiosperms in an alpine lake, Taiwan
AUTHOR	Yuan-Hsun Hwang Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China Chiou-Fang Liou Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China I-Szu Weng Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China
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ABSTRACT	Seasonal variations of nutrients in the lakewater, porewater in the lake sediment, and tissues of dominant aquatic angiosperms, Schoenoplectus mucronatus (L.) Pall. subsp. robustus (Miq.) T. Koyama and Sparganium fallax Graebn., in the Yuan-Yang Lake were studied. Nutrients in the lakewater were scarce and did not vary significantly between seasons. The porewater, in general, had higher concentrations of nutrients than the lakewater. The nutrient concentrations of porewaters were varied among sampling sites. Decomposition of organic matters in the lake and geographical characteristics of the watershed are the sources of differences in nutrient contents among sampling sites of porewaters in the lake. Higher contents of dissolved organic carbon and ammonium and potassium ions in the porewater were found in sites of water entrance areas. High contents of Ca and Mg ions in the lakewater and porewater were only found in the northwestern site of the lake. Nitrogen and potassium, which are concentrated in the aboveground tissues, are the major elements in tissues of dominant aquatic angiosperms. Nitrogen and potassium were consumed luxuriously before the growing season, and the contents in tissues gradually decreased during the growing period. However, no obvious seasonal change was found for Na, Ca, and Mg. The yearly budget of uptake and loss of nutrients through Sparganium fallax is estimated to be 13.8 g m-2 N, 1.1 g m-2 P, and 19.8 g m-2 K in 1997, and 9.9 g m-2 N, 0.6 g m-2 P, and 9.2 g m-2 K in 1998.
KEYWORD	Nitrogen; Nutrients; Potassium; Schoenoplectus mucronatus ssp. robustus; Sparganium fallax; Yuan-Yang Lake;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 41 Number 4 October 2000, page 275-282, 8 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China