碩士 / 國立臺灣師範大學 / 生命科學研究所 / 97 / The purpose of this study is to investigate how the Asian dust storm (AD) affects organic carbon cycling in the Kuroshio Water. Samples were collected from a station (123° 10’ °E ; 25° 5’ °N) located in the Kuroshio, northeastern of Taiwan during the AD season in March, 2006. To compare, the AD event is defined as aerosol [Al] >3000 ng m-3, and the pre-AD and the after-AD periods refer to 3 days prior to and after the AD event, respectively. Results showed that the biogeochemical parameters, including nitrate (NO3- ; 0.16 ± 0.04 μM), chlorophyll a (Chl-a; 0.50 ± 0.16 mg Chl m-3), primary production (PP；9.95 ± 4.73 mg C m-3 d-1), biomass (BB; 5.61 ± 0.56 mg C m-3) and production (BP; 1.01 ± 0.12 mg C m-3 d-1) of heterotrophic bacteria increased significantly in the AD period compared to the pre-AD period. Even more, the BB reached maximum (5.93 mg C m-3) in the after-AD period. Further analyses suggest that growth of phytoplankton has been stimulated by iron elements from aerosol deposited during the AD period. This assumption can be supported by the significant relationships observed between PP and water-soluble iron concentration (r = 0.94, p < 0.05) and between phytoplankton turnover rate (Pμ) and Fe-soluble (r = 0.90, p < 0.05). In addition, a significant relationship was evident among the average values of dissolved organic carbon (DOC), Chl-a, and BB, and it can be expressed as following, IDOCavg = 1762.4 × IChl-aavg - 487.3 × IBBavg + 3302 (r2 = 0.94, p < 0.01). This result suggests that DOC concentration increased with growth of phytoplankton. In turn, the abundant DOC served as substrate for heterotrophic bacteria. As the P/R ratio, the mean ± SD value was 0.45 ± 0.40, and it suggests that the Kuroshio Water ecosystem was heterotrophic. Notably, the P/R ratio was larger than 2 in the surface water (< 25 m) during the AD period. It indicates that organic carbon produced by robust growth of phytoplankton in the surface water was more than sufficient for the consumption of plankton communities, and it can be expected that there was residual organic carbon exported into other systems.
| Identifer | oai:union.ndltd.org:TW/097NTNU5105019 |
| Date | January 2009 |
| Creators | Fu-Chun Chen, 陳富群 |
| Contributors | Chung-Chi Chen, 陳仲吉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 72 |
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