Compound-Specific Radiocarbon Analysis of Organic Compounds from Mount Fuji Proximal Lake (Lake Kawaguchi) Sediment, Central Japan
Compound-Specific Radiocarbon Analysis of Organic Compounds from Mount Fuji Proximal Lake (Lake Kawaguchi) Sediment, Central Japan
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DOI：
10.1017/rdc.2019.158
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发表时间：
2020-01
期刊：
影响因子：
8.3
通讯作者：
Shinya Yamamoto;Y. Miyairi;Y. Yokoyama;Hisami Suga;N. Ogawa;N. Ohkouchi
中科院分区：
文献类型：
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作者：
Shinya Yamamoto;Y. Miyairi;Y. Yokoyama;Hisami Suga;N. Ogawa;N. Ohkouchi
通过对日本中部富士山北方山麓川口湖表层沉积物中有机化合物的放射性碳含量（Δ 14 C）测定，揭示了火山区沉积有机化合物的不同来源。C16脂肪酸（−124‰）和叶绿素a（−133‰）的Δ 14 C值与地表水中溶解无机碳（DIC）的Δ 14 C值（−117‰）相似，表明这些化合物中有很大一部分来自现代初级生产者，其储层年龄约为1000年。另一方面，叶绿素a的Δ 14 C值（−133‰）与132，173-环脱镁叶绿酸-a-烯醇（−169‰）和脱镁叶绿素a（−179‰）的Δ 14 C值之间存在很大的偏移，表明来自较老的色素。此外，长链（C24、C26和C28）脂肪酸的Δ 14 C（−183至−75‰）与沉积物中植物叶片残留物的Δ 14 C（0‰）有很大的偏移，表明长链脂肪酸受到了来自老化前陆地物质的大量贡献的影响。总的来说，沉积有机化合物给出的14 C年龄比沉积物中的植物叶片碎片更老;然而，C16脂肪酸和DIC的Δ 14 C之间的相似性意味着在火山湖环境中应用化合物特异性放射性碳分析作为测年工具的潜力。
ABSTRACT Differential sources of sedimentary organic compounds in a volcanic region were revealed by determining radiocarbon content (Δ14C) of organic compounds in surface sediments from Lake Kawaguchi, at the northern foot of Mount Fuji, central Japan. The Δ14C values of C16 fatty acid (−124‰) and chlorophyll a (Chl a) (−133‰) were similar to the Δ14C of dissolved inorganic carbon (DIC) in surface water (−117‰), suggesting that a significant portion of these compounds originated from modern primary producers with a reservoir age of ~1000 years. On the other hand, a large offset between the Δ14C values of Chl a (−133‰) and those of 132, 173-cyclopheophorbide-a-enol (−169‰) and pheophytin a (−179‰) suggested contributions from older pigments. In addition, the Δ14C of long-chain (C24, C26, and C28) fatty acids (−183 to −75‰) showed a large offset from that of a plant leaf remain (0‰) within sediments, demonstrating that the long-chain fatty acids were affected by substantial contributions from pre-aged terrestrial materials. Overall, the sedimentary organic compounds gave 14C ages older than the plant leaf fragment within sediments; however, the similarity between Δ14C of the C16 fatty acid and DIC implies potential for applying compound-specific radiocarbon analysis as a dating tool in volcanic lake environments.