碩士 / 國立臺灣海洋大學 / 海洋環境與生態研究所 / 107 / Nanoflagellate (NF) is the major bacterial grazer in the aquatic ecosystems. Cause the carbon-nitrogen ratio of Protist (average C:N is 6.8:1) is higher than the ratio of bacteria (average C:N is 5.2:1), nanoflagellate will release excess nutrients (such as nitrogen) during the process of grazing, and these nutrients will be quickly used by bacteria afterword. These regenerative nutrients maybe an important factor in the growth of bacteria. Unfortunately, currently there isn’t much research on the amount of regenerative nutrient released during the grazing process of nanoflagellates. In this study, we executed 24-hours culture experiment with additional 15N labeled bacteria, carry out on the northeast coast of Taiwan in July 2018, in order to understand the effects of renewable nutrients excreted by nanoflagellate on the bacteria growth. The experiment was divided into two groups, one containing nanoflagellate (<20 μm), and the other one without nanoflagellate (<0.8 μm). The samples of particulate organic nitrogen (PON) is 15N content and bacterial production (BP) were taken after cultured for 0, 2, 4, 8, 12 and 24 hours. Furthermore, NanoSIMS samples were collected after 24 hours of culturing. The results of NanoSIMS shown that 15N has been widely distributed throughout the water when the experiment been terminated. Almost all bacteria and pigmented nanoflagellate (PNF) have found 15N inside their body, while only a few heterotrophic nanoflagellate (HNF) are without containing 15N inside their body. The results of the analysis showed that bacterial production of the group containing nanoflagellates (<20 μm) is significantly higher than the group without nanoflagellates (<0.8 μm) after 12 hours of culture. Therefore, regenerative nutrients produced by nanoflagellate grazing have a significant effect on bacterial growth. We consider the absorption of bacterial growth is the factor effecting the increase in particulate organic nitrogen, while the lysis and metabolism of bacteria or the emission by nanoflagellate grazing maybe the factors effecting the reduction of particulate organic nitrogen during the experiment. Comparing PO15N and bacterial production data and further analysis. Found positive correlation between regenerative nutrients (0.11-0.83 mgN m-3h-1) produced by grazer emission and bacterial production of the group containing nanoflagellates. Based on this study, it that the regenerative nutrients produced by nanoflagellate during grazing is important for the growth of bacteria in the northeastern coast of Taiwan.
| Identifer | oai:union.ndltd.org:TW/107NTOU528A005 |
| Date | January 2019 |
| Creators | Li, Yan-Min, 李言敏 |
| Contributors | Chiang, Kuo-Ping, 蔣國平 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 31 |
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