2008-08-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/693647摘要：高屏溪每年往外海輸出49百萬噸的懸浮顆粒，大量的懸浮顆粒及陸源有機碳藉由河川向深海傳輸及埋藏將會對周圍海域沉積物之分佈及有機碳之埋藏通量有所影響。大量陸源有機碳的傳輸與埋藏亦提供了沉積物中硫酸鹽還原作用主要的有機碳來源，但有機碳的量及質對於沉積物硫酸鹽還原作用之影響仍不是非常清楚。高屏溪常年輸出大量陸源有機碳至高屏外海埋藏，“陸源”有機物之埋藏佔60%以上，有機碳的品質（陸源及海源）的差異是否對於沉積物中硫酸鹽還原作用亦有所影響，目前的研究仍不多。而硫酸鹽還原作用是沉積物中主要的有機碳分解反應。沉積物硫酸鹽還原作用之快慢將影響有機碳沉降至沉積物後是否能有效的保存及深埋。因此沉積物硫酸鹽還原作用之研究亦是探討陸源有機碳“宿命”相當重要的一環。 本年度本研究將針對陸海源有機碳之差異對於沉積物硫酸鹽還原作用的影響與有機碳之分解及深埋效率作為研究重點。本研究將於高屏峽谷以南水深1000至2500公尺以深之海域進行沉積物岩心之採集，藉由沉積物顆粒大小、有機碳含量、埋藏通量、有機碳碳-13同位素訊號、沉積物C/N比值及沉積物生地化變化（硫酸鹽還原作用）等分析，探討高屏溪輸出之陸源有機物是否被傳輸至較深的海域埋藏，並進一步比較深水海域陸源有機碳之埋藏通量與高屏陸棚陸坡海域之差異。此外，本研究將探討有機碳之來源（陸源或海源），且探討有機碳埋藏於沉積物後之生地化變化，探討沉積物硫酸鹽還原作用及有機碳於沉積物中之消耗分解速率，並進一步探討沉積物硫酸鹽還原作用利用有機碳之種類。本研究期能利用有機碳埋藏通量、有機碳來源與品質（陸源或海源、C/N比值）及硫酸鹽還原作用來探討比較高屏溪輸出之顆粒有機碳之分解及深埋效率於高屏溪外海陸棚及陸坡海域的差異，以更深入的探討高屏溪對於外海陸源物質傳輸及沉積物生地化反應的重要性。 <br> Abstract: Kaoping River exports very large amount of suspended particles, approximately 49 million tons/year, and an unknown fraction of organic carbon to the ocean. However, limited information is available concerning fate of these large amounts of inorganic particles and terrigenous organic carbon in the ocean. These large amounts of terrigeous organic carbon also provide a carbon source to bacterial sulfate reduction in the sediment. Because bacterial sulfate reduction is the major process in oxidizing organic carbon in the anoxic sediment, a lack of understanding about oxidation of terrigenous organic carbon in anoxic sediments will hinder a better evaluation of the fate of terrigenous organic carbon. In this project, we intent to study spatial and vertical (temporal) organic carbon deposition in sediments offshore southwestern Taiwan and also to examine the role of terrigenous organic carbon on sulfate reduction and subsequent burial efficiency. Our main objectives are to examine the influence of terrigeous organic carbon depositon on the sulfate reduction and to identify the relationships between the sulfate reduction rate and the quality as well as quantity of organic carbon in sediments offshore KP. In our proposed project, we like to sample a series of cores at water depth range between 1000 to 2500m on the continental slope southern Kaoping Canyon. Sulfate reduction rates, organic carbon and carbonate contents, C/N ratio as well as grain sizes will be analyzed. Spatial organic carbon deposition rate and sulfate reduction rates will be used to construct a model in understating the burial of terrigenous organic carbon in the continental margin sediments offshore a small mountainous subtropical river.