| Summary: | 碩士 === 國立成功大學 === 地球科學系碩博士班 === 93 === This study was to investigate the degradation of organic matters by bacteria with temporal and spatial variations in the salt marsh wetland sediments of the Syh-Tsao Wildlife Conservation Area, with the objective of determining relationships between degradation rates of organic matters and environmental factors. Amounts（100-7560 mg kg-1） and rates（0.02-9.25 mg kg-1 hr-1） of organic matters degradation were higher（about 14.14％ in amounts and 8.82％ in rates） in pond C as compared to those of the pond A in the salt marsh. Organic matter degradation had irregular changes in different depths and were higher in surface soils and decreased with depth. Rates of organic matters degradation ranged from 0.07-8.85 mg kg-1 hr-1 in 0-10 ㎝ soil layer and decreased with depth. The degradation rates（0.17-9.25 mg kg-1 hr-1） of organic matters in August through December were significantly greater than those in other months and seasons during the study period. Degradation rates of organic matters were significantly related to the nitrate, sulfate, and temperature in pond A（0.385＜r2＜0.507, p＜0.05）, and to the chloride, pH, and sulfate in pond C（0.562＜r2＜0.648, p＜0.05）. Bacterial activity was influenced by temperature and exposure of soil to O2, as it occurred in periods of low rainfall or low water level. The increase in bacterial activity contributes to enhance the degradation rates of organic matters and cycling of nutrients in wetlands. The results showed that environmental factors play an important role in the regulation of organic matters degradation. Increased turnover of organic matters may lead to increase the supply of bioavailable nutrients to emergent macrophytes and periphyton and higher nutrient concentrations in water.
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