碩士 / 國立中央大學 / 水文與海洋科學研究所 / 104 / The Danshuei River is located in northern Taiwan, where the nitrogen concentration is higher than the most rivers in the world [Wen et al., 2008]. The eutrophication phenomena in the Danshuei River sometimes led to severe hypoxia. In order to understand the occurrence of the hypoxia, we surveyed nutrient concentration, chlorophyll a and dissolved oxygen in the Danshuei River during October 2014 to August 2015. In addition, I measured the community respiration rate (CR) and primary productivity (PP) to understand the mechanisms of the consumption and production of oxygen in the Danshuei River.
The results show hypoxic zones of the Danshui River occurred in 20-30 km away from the estuary, from the Zhongxing Bridge (D3) to the Chenglin Bridge (D7). The most serious hypoxia occurred in the fall. The averaged CR was 111.2 ± 14.3 mmol O2 m-3d-1. Higher oxygen consumption occurred at D3-D7 where the highest CR reached 266.2 mmol O2 m-3d-1. The averaged primary production was 13.2 ± 4.03 mmol O2 m-3d-1. The highest PP occurred at Ganyuan Bridge (D9) and the Sanying Bridge (D10) was 50.4 mmol O2 m-3d-1. Comparing the measured PP and CR in Danshuei River with that in other rivers around the world, we found that the measured PP in Danshuei river is relatively low, and the measured CR is much higher than that in other rivers.
Comparing to the biogeochemical modeling results, the distribution and magnitude of PP I measured were similar to previous modeling results in Danshui River [Lin, 2015]. However, the measured CR were all much higher than previous modeling results (25-120 mmol O2m-3d-1). The biogeochemical model used by Lin (2015) can not well describe the mechanism of oxygen consumption and production, and more investigations are needed for model verification.
| Identifer | oai:union.ndltd.org:TW/104NCU05761005 |
| Date | January 2016 |
| Creators | Chin-An Zhang, 詹景安 |
| Contributors | Shao-Yiu Hsu, 許少瑜 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 96 |
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