Paleoenvironmental Changes in the Eurasian Continental Interior during the Last 12 Million Years Derived from Organic Components in Sediment Cores (BDP-96 and BDP-98) from Lake Baikal

Geochemical features of biomarkers in foam substances from the Chikugo River system in the Hita City area, Oita Prefecture

“…試料 日田市地域の筑後川水系の三隅川，大山川，玖 珠川等における現地調査は，2015 年 2 月 3 日～5 日にかけて実施し，泡状物質，マット状浮遊藻類 および礫上の付着藻類試料を採取した (図 1， 表 1) ． 試料採取はステンレスパイプをつけたひしゃくや スパチュラを用い，スクリュウキャップ付ガラス 瓶(100 mL)に採取し，冷凍し大学の研究室に輸 送して冷凍保存した．気温は 4.9～9.5℃，水温は 5.5～9.3℃，電気伝導度は 10.85～15.15 mS/m， pH は 7.23～7.72 であった(表 1) ．泡状物質の分 布状況の主な写真を図 2 に示す． 2.2. 方法 バ イ オ マ ー カ ー の 分 析 は Matsumoto et al [8][9] [10] および Matsumoto and Watanuki [11] の方 法に準じて行った．泡状物質よび藻類懸濁物を含 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 …”

“…)によってはコレ ステロールを多く含むケースがある [28] ．Navicula spp., Nitzschia spp.は三隈川などに分布する珪 藻である [29] (矢野ほか，2005) ．24-エチルコレス テロールは主として維管束植物に由来する [10] …”

Paleoenvironmental changes in northwest Mongolia during the last 27 kyr inferred from organic components in the Lake Hovsgol sediment core record

“…Some natural organic components are biomarkers of biological production, aquatic (autochthonous) and terrestrial (allochthonous) sources, and paleoenvironmental changes in the drainage basin (e.g., Meyers and Ishiwatari 1993;Matsumoto et al 2000Matsumoto et al , 2003Matsumoto et al , 2006Matsumoto et al , 2010. Biomarkers are widely used to evaluate sources and sedimentary conditions of organic matter in various environments, including Lake Baikal (BDP96&98) sediment cores for 12 Ma (Matsumoto et al 2000(Matsumoto et al , 2003 and Lake Hovsgol sediment core for 1 Ma (Matsumoto et al 2008;Tani et al 2009).…”

“…Biomarkers are widely used to evaluate sources and sedimentary conditions of organic matter in various environments, including Lake Baikal (BDP96&98) sediment cores for 12 Ma (Matsumoto et al 2000(Matsumoto et al , 2003 and Lake Hovsgol sediment core for 1 Ma (Matsumoto et al 2008;Tani et al 2009). Here we report on a detailed study of organic components [TOC, total nitrogen (TN), hydrocarbons, fatty acids and sterols] in a dated X106 sediment core from Lake Hovsgol to elucidate biological production, sources of organic matter, and paleolimnological and paleoenvironmental changes during the last 27 cal kyr BP in northwest Mongolia.…”

“…High latitude areas and northeast Eurasia, including the Lake Hovsgol area, are sensitive to climatic changes (Short et al 1991) and thus the best sites for the study of paleoenvironmental changes. A large amount of information on paleoenvironmental changes of the earth has been obtained by the analyses of marine and lake sediment cores, including Lakes Baikal and Hovsgol, and ice cores (e.g., Shackleton et al 1990; Raymo and Ruddiman 1992;Horiuchi et al 2000;Kashiwaya et al 2001;Matsumoto et al 2003;Soma et al 2007;Hovsgol Drilling Project Members 2009;Tani et al 2009;Watanabe et al 2009;Murakami et al 2010).…”