碩士 / 國立臺灣海洋大學 / 海洋環境化學與生態研究所 / 102 / Abstract
Global warming will increase the frequency of extreme weather, especially in the marine biogeochemical cycle. Therefore, global warming is definitely an important topic in the global change research field. The oligotrophic northwestern Pacific ocean appears to be a nitrogen-limited system, also typhoons occur frequently in this area. Because of hard to get the in situ data. So this study utilized two cruises to get in situ data before, and after Typhoon Soala passes (during 26 July to 6 August 2012). We conducted our research from eastern Taiwan to 124 oE. In this area, we set nine long-term observation sampling stations 15 nm apart.
Our study result shows that after typhoon, mixed layer depth deepened from 23±6 m to 45±11 m (approximately 99%), and sea surface chlorophyll a concentration increased from 0.15±0.03 mg m-3 to 0.21±0.03 mg m-3. Since the study area was an oligotrophic ocean, chlorophyll was highly concentrated in the subsurface of the ocean. Typhoon enhanced ocean vertical mixing, which increased sea surface chlorophyll a concentration. After typhoon, integrate chlorophyll a concentration significant increased form 29.6±3.4 mg m-2 to34.5±6.0 mg m-2(P<0.05). Furthermore, chlorophyll a concentration increased at subsurface and chlorophyll max depth became shallow from chlorophyll a profile. That is because of nitracline depth shallower than others stations before typhoon. Since the intense wind of typhoon can induce strong ocean mixing, deeper-ocean nutrient could be brought to the euphotic zone and increase in phytoplankton biomass(4.96±3.64 mg m-2). And the Stations are 60% controlled by cold eddy. After typhoon, primary production decreased from 265±91 mgC m-2 d-1to 229±46 mgC m-2 d-1. Since the primary productivity decreased, we speculated that phytoplankton does not suit the environment yet. So primary production cannot be increased with phytoplankton biomass. Previous studies of typhoon induced phytoplankton bloom are largely based on satellite remote sensing data. And based on our data, the increase of sea surface chlorophyll a concentration should result in a higher primary production. But in our study result, we cannot get the same outcome as other's model-based productivity calculation. It is necessary to adjust other's model-based calculation and research approach.
| Identifer | oai:union.ndltd.org:TW/102NTOU5282006 |
| Date | January 2014 |
| Creators | Kao, Kai-Jung, 高愷嶸 |
| Contributors | Gong, Gwo-Ching, 龔國慶 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 56 |
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