This study used Vanadium (III) reduction- chemiluminescence method to measure the very low concentration of nitrite plus nitrate (N+N) in oligotrophic seawaters with a detection limit of 0.7nM. In addition, the high temperature catalytic oxidation (HTCO) ¡V chemiluminescence method was applied to determine the concentration of total dissolved nitrogen (TDN) with a detection limit of 0.5£gM based on a volume of 150£gL seawater. Both methods have high degree of precision and accuracy. Furthermore, the Magic method and persulfate oxidation method were conducted to measure the concentrations of soluble reactive phosphorus (SRP) and total dissolved phosphorus (TDP) with detection limits about 10 nM (original seawater) and 100 nM, respectively. All these analytical methods meet the ranges of parameters in most oligotrophic oceans.
According to the hydrology data, the Kuroshio of east Taiwan may be classified into four types: 1. Kuroshio Waters affected by the East China Seawater (ECS-KW)¡F2. typical Kuroshio Waters (KW)¡F3. Kuroshio Waters affected by the South China Seawater (SCS- KW) and 4.Kuroshio waters affected by riverplume (plume- KW). In the euphotic zone, the concentrations of N+N, SRP, DON and DOP in the plume-KW are about 0.6 ~ 4 £gM, 0.03 ~ 0.4 £gM, 2 ~ 6 £gM, and 0.05 ~ 0.2 £gM, respectively, higher than those in other type waters. The plume-KW is apparently influenced by the input of freshwater. Besides, the nitrogen and phosphorus species in the SCS-KW and ECS-KW are higher than those in the KW. Positive correlations are significant between Ch1 a and DON and DOP, indicating that biological activity controls primarily on the distributions of DON and DOP in the euphotic zone.
KW has oligotrophic characteristics, and in the euphotic zone, the concentrations of N+N and SRP are generally lower than those in other water types. The Chl a has positive correlations with DON and N+N, resulted likely from their same features of subsurface maxima. The ratio between N+N and SRP in the euphotic zone is about 0.02~0.15, and the value increases gradually in deep water, and eventually close the Redfield ratio. Judging from the distribution of the nitrate anomaly (2.5~ 1.5£gM), nitrogen fixation may prevail in the KW.
The N+N and SRP values in the euphotic zone in the SCS-KW near the southeastern coast of Taiwan are about 0.02£gM higher in spring than in summer. DON and DOP are also about 1~2.5£gM and 0.02~0.2£gM higher, respectively, in spring than in summer. This feature may be caused from getting stratification torward the summer season in the SCS-KW.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0910108-171354 |
| Date | 10 September 2008 |
| Creators | Cai, Sheng-xian |
| Contributors | Yu-chia Chung, Yhu-ling Lee, Jia-jang Hung |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0910108-171354 |
| Rights | off_campus_withheld, Copyright information available at source archive |
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