Sources of dissolved organic carbon of Yuan-Yang Lake
Date Issued
2011
Date
2011
Author(s)
Chou, Ming-Hsuan
Abstract
Yuan-yang Lake is a subalpine lake situated in northern Taiwan. The lake water is characterized by brown color with low pH. In order to know more about the role of dissolved organic carbon (DOC) in the lake ecosystem, this study is attempted to elucidate the sources of DOC and its effect on algae in this lake. Litters from dominant plants, rhododendron and cypress, and epiphytic liverworts were collected and used for leaching experiments. In addition, surface soil of forest was collected and extracted for comparison with lake water. The results showed that DOC in lake water was contributed mainly by the refractory, humic substances (HS). High values of SUVA254 in lake water suggested that it is in high degree of aromaticity. The acidity of leachates from epiphytic liverworts was higher than rain water. The amount of precipitates was an important factor that affected the DOC concentration, pH, and color (A440) in lake water. The results of excitation-emission matrices (EEMs) and high performance liquid chromatographic (HPLC) analysis showed that a high similarity existed between the fluorescence plots and molecular weight spectra between lake water and the leachates of rhododendron and epiphytes, suggesting that DOC in lake water should be mainly allochthonous in origin. In experiments of cultivating the algae isolated from lake with DOC, it is revealed that algae grew faster in higher concentrations of DOC. The plots of EEMs showed that algal cells produced low molecular weight molecules and high molecular weight HS. However, owing to low algal density in lake water, the role played by the algal-derived DOC in lake water was minor and could be negligible. The source of DOC and its effects on algae in this lake were discussed. This study provides data showing that the DOC in YYL is contributed mainly by the leachates from forest under-layers and epiphytes.
Subjects
Yuan-Yang Lake
dissolved organic carbon (DOC)
humic substance (HS)
SUVA254
A440
HPLC
EEMs
Type
thesis
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