Permafrost carbon pool destabilization causes substantial fluvial export of soil carbon, yet the export patterns and magnitudes are not well understood. Here we investigated the radiocarbon ( 14 C) in dissolved organic and inorganic carbon (DOC and DIC, respectively) exported from a mid-sized river in the central Qinghai-Tibet Plateau (QTP) permafrost region. We utilized the radiocarbon dating technique to reveal the ages of riverine dissolved carbon and a statistical model to partition the riverine carbon from different age categories. DOC and DIC showed bomb-depleted 14 C signatures corresponding to millennial ages. Seasonally, 14 C-depleted DOC and DIC ages were associated with active layer thaw and flow path deepening. Spatially, older DOC and DIC were found in the valley sites correlated with warmer permafrost and higher groundwater flow. Further, isotopic mixing models suggested that 83 ± 27% of riverine DOC was derived from active layer and pe...

中文翻译：

---

变暖和季风气候导致青藏高原多年冻土流域大量出口千禧年龄的碳

多年冻土的碳库失稳导致大量的土壤碳汇流失，但其出口方式和幅度尚不清楚。在这里，我们研究了从青藏高原中部多年冻土区中型河流输出的溶解有机碳和无机碳（分别为DOC和DIC）中的放射性碳（14 ​​C）。我们利用放射性碳测年技术揭示了河流溶解碳的年龄，并利用统计模型对不同年龄类别的河流碳进行了划分。DOC和DIC显示出与千禧年时代相对应的炸弹耗尽的14 C签名。季节性地，有14个C耗尽的DOC和DIC年龄与活性层融化和流径加深有关。在空间上，在山谷地区发现了较旧的DOC和DIC，这与多年冻土层变暖和地下水流量较高有关。