Nutrient dynamics of two aquatic angiosperms in an alpine lake, Taiwan
Journal
Botanical Bulletin of Academia Sinica
Journal Volume
41
Journal Issue
4
Pages
275-282
Date Issued
2000-10
Author(s)
Yuan-Hsun Hwang
Chiou-Fang Liou
I-Szu Weng
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.
Subjects
nitrogen
nutrients
potassium
Schoenoplectus mucronatus ssp robustus
Sparganium fallax
Yuan-Yang Lake
Type
journal article