| Summary: | 碩士 === 國立中興大學 === 生命科學系所 === 100 === There are number of springs pits found in Jingmei river and the dissolved oxygen in them is relatively higher than in river water column. This study hypothesized that the high dissolved oxygen detected in spring pits is caused by algal photosynthesis. The maximum saturated gross primary productivity (PBm) of phytoplankton were observed outside of the spring pits in different seasons, and were higher than in the spring pits. The respiration rate observed outside of the spring pits in different season were higher than the spring pits, too. PBm and respiration rate of periphyton inside the spring pits in winter were higher than in the river. Biomass of phytoplankton in the spring pits is higher than outside river. But Biomass of periphyton in winter is outside river higher than spring pits indicating that the high dissolved oxygen in spring pits was not caused by algal photosynthesis. The pH value inside and outside the pits showed no significant difference, indicates that there is no effect of transformation of carbon dioxide to oxygen through algal photosynthesis on the observed dissolved oxygen. In addition, no significant difference was observed in temperature between inside and outside the spring pits, indicated that temperature was not the main reason affecting the dissolved oxygen in spring pits. Besides, diatom species outside the spring pits tends to tolerant heavy pollution species, and diatom diversity in spring pits is higher than outside river. Therefore, relative higher dissolved oxygen in spring pits is not caused by algal photosynthesis.
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