碩士 / 國立臺灣大學 / 海洋研究所 / 91 / A total of 14 vertical profiles of Th-234 were determined at the time-series station (18°N, 116°E) in the South China Sea from September 1998 to March 2003. Significant deficiencies of total Th-234 with respect to U-238 were found in the upper 300m layer, from which the Th-234 sinking fluxes of 758~2406 dpm/m2/d with an average value of 1576 dpm/m2/d at the depth of 100m and 1895~6449 dpm/m2/d with an average value of 4119 dpm/m2/d at the depth of 300 m were estimated from the irreversible scavenging model. The average residence time of total Th-234 with respect to the vertical flux at 100m was 156 day.
Assuming thorium can serve as an efficient tracer for the particulate organic carbon (POC) in the euphotic zone, the POC/PTh-234 ratios in the particles colleted by 0.45m filtration were used to convert Th-234 fluxes to the POC fluxes. Accordingly, the POC export fluxes range from 3.4 to 10.7 mmol C/m2/d at 100m. Theses values are systematically higher than the estimation based on the biogeochemical model by Liu et al. (2002).
| Identifer | oai:union.ndltd.org:TW/091NTU00279050 |
| Date | January 2003 |
| Creators | Chun-Ming Lin, 林俊銘 |
| Contributors | Ching-Ling Wei, 魏慶琳 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 0 |
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