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Title: | 河海連續系統之有機顆粒成分變化:以卑南河系為例 Compositional changes of organic particulates along river-ocean continuum: An example of Beinan system |
Authors: | Yun-Hsuan Lee 李芸瑄 |
Advisor: | 王珮玲(Pei-Ling Wang) 王珮玲(Pei-Ling Wang | plwang@ntu.edu.tw | ), |
Keyword: | 造山帶河川,卑南溪,顆粒態有機碳,碳同位素, Small Mountainous Rivers,Beinan river,Particulate organic carbon,Carbon isotope, |
Publication Year : | 2022 |
Degree: | 碩士 |
Abstract: | 在各種調控大氣二氧化碳濃度的作用中,陸地岩石的化學風化和陸源有機物的輸出與埋藏是重要機制,尤其後者對大氣中二氧化碳而言應是重要的淨消耗,因此需要研究河川在傳輸陸源有機物時從陸地到海洋的轉變,解析其從源到匯的變化與調控機制。 本研究選擇臺灣沈積物傳輸通量最高的卑南溪流域作為研究題材,藉由分析河川與海洋沈積物之元素含量和有機碳同位素等特徵,以探討河域及海域沈積物中顆粒態有機碳的來源,檢視懸浮顆粒與底泥間以及卑南溪流域上游至下游的變化,並分析淺層海洋沈積物之地球化學特徵的空間分佈,探討陸源性有機碳經由河川進入鄰近海域之陸棚坡區域後的傳輸與轉變。結果顯示卑南溪流域主要是以岩石作為該河域之顆粒態有機碳的主要來源,在同站位點中的懸浮顆粒樣本顆粒大小應較底泥小,且較細顆粒的沈積物擁有較強的吸附有機物能力,使得懸浮顆粒樣本的有機物相較於底泥富集。在卑南溪流域處於高流量、高水位時期,較容易從周遭陸地上挾帶較多的土壤或是土壤之外的物質進入河域系統中。根據在卑南溪口外海佈放的沈積物收集器所收集的資料,可知當雨量豐沛時,距離出海口較近的沈積物收集器能收集到較多且可能顆粒較粗的沈積物,但距離出海口更遠後只剩下顆粒較細的沈積物得以懸浮在海水中進行沉降,雨量多寡並未對造成有機物特徵改變。卑南溪口外海淺層沈積物與出海口的懸浮顆粒、底泥的特徵接近,顯示此海域之顆粒態有機物來源主要是以河川傳輸的陸源物質為主,此外由海洋岩心表層沈積物的 14C 年代分析得知在該海域所接收到的有機碳中有高比例的老碳。綜合上述,本研究推測卑南溪流域以岩石作為顆粒態有機碳的主要來源,而卑南溪外海的海域沈積物也是以陸源輸出的沈積物為主。 Among the various pathways for regulating atmospheric CO2 concentration, chemical weathering of rocks on land and burial of terrestrial organic carbon from land to ocean by rivers represent the major pathways. The latter, in particular, is expected to be an important net consumption of atmospheric CO2. As a result, it is vital to investigate the transition of rivers from land to sea while conveying organic materials, as well as the change and regulating mechanisms from source to sink. The Beinan River catchment has demonstrated the highest sediment transport flux in Taiwan and is an excellent study target. This study aims to analyze the elemental content and carbon isotope composition of organic carbon in sediment to investigate the source of particulate organic carbon in the river and marine sediment and to reveal the changes between suspended particles and sediments from upstream to downstream of the Beinan River. Our observation show that rocks are the primary source of particulate organic carbon in the Beinan river system. The grain size of the suspended particle at the same station would be smaller than that of the sediment, resulting in an enrichment of organic matter in the suspended particle than that in the sediment. When the Beinan River catchment was experiencing high flow and water levels, extra soil or other material was delivered into the river system. The data from two sediment traps placed offshore of the Beinan River demonstrated that the sediment trap closer to the river mouth can receive more sediment during a heavy rainfall period with different characteristics (higher TN, TOC, and C/N ratio) from that collected during a less rainfall period. Instead, the sediment collected at the trap far from the river month shows no difference between heavy and fewer rainfall periods. The surface marine sediment offshore of the Beinan river shows similar characteristics to the suspended particle and sediment in the estuary, suggesting that the particulate organic matter in near offshore sediment is primarily from land and transmitted by the river. Furthermore, the 14C analysis of TOC in the surface sediment offshore shows a high proportion of old carbon. In conclusion, this study demonstrates that the primary source of particulate organic carbon in the Beinan river system is rock, and the marine sediment offshore of the Beinan river is also dominant with terrestrial materials. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/84122 |
DOI: | 10.6342/NTU202204038 |
Fulltext Rights: | 同意授權(限校園內公開) |
metadata.dc.date.embargo-lift: | 2022-09-29 |
Appears in Collections: | 海洋研究所 |
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U0001-2609202207495000.pdf Access limited in NTU ip range | 9.4 MB | Adobe PDF | View/Open |
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