Isotopic indicators of source and fate of particulate organic carbon in a karstic watershed on the Yunnan-Guizhou Plateau

Source and flux of POC in a karstic area in the Changjiang River watershed: impacts of reservoirs and extreme drought

“…6) indicated that POC contents (%) of SPM were diluted with the inorganic constituents derived from soil erosion. This was similar to other rivers (Ludwig et al, 1996;Jiang and Ji, 2013;Zhang et al, 2009). The positive correlation between TSS concentrations and POC contents (µmol L −1 , Table S2) indicated that terrestrial organic matter was an important source of POC in SPM, which confirmed the erosion process.…”

“…(Li and Ji, 2016). Kendall et al (2007) (Kendall et al, 2001;Jiang and Ji, 2013). This process was confirmed by the significant positive correlation of δ 15 N TN -SPM vs. δ 15 N-NO − 3 and δ 15 N TN -SPM vs. NO − 3 in May (Fig.…”

“…7b) and δ 15 N TN (Fig. 7c) between suspended and surface sediments indicated that an intense exchange might exist in these two carbon pools (Jiang and Ji, 2013;Sarma et al, 2012). The resuspension/deposition of suspended matter with mixing of different organic matter sources might result in the significant correlation of δ 13 C POC (Fig.…”

“…Sampling of SPM were conducted by filtration through precombusted (450 • for 6 h) and preweighted 47 mm glass fiber filters for SPM weight concentrations and stable isotopic analyses of carbon and nitrogen. Surface sediments were collected using a 0.05 m 2 Van Veen grab (Jiang and Ji, 2013). All samples were stored in a freezer (≤ 20 • ) prior to laboratory analyses.…”

The role of biological carbon pump in the carbon sink and water environment improvement in karst surface aquatic ecosystems

“…28 5 和29 5,22 被认为是来自于陆源植物的甾醇 [34,35] . [29] C/N 单同位素法 [27,28]  13 C,  15 N 双碳同位素法 [32]  13 C+ 14 C 生标法 正构烷烃 [34] C 27 , C 29 , C 31 , C 17 等 脂肪酸 [34] SCFAs, MUFAs, LCFAs, PUFAs 甾醇 [34] 29 5 , 28 5 , 29 [36] 的研究表明, 美国密西西比河的内源有机碳占总有 机碳的比例约为60%. 最新模拟实验研究也显示 [37] , [22,23] , 富营养化的控制元素是氮(N)和磷(P) [38~40] .…”