永久冻土
支流
溶解有机碳
环境科学
二氧化碳
碳同位素
北极的
土壤水分
碳循环
碳酸盐
碳纤维
温室气体
放射性碳年代测定
无机碳总量
碳汇
总有机碳
环境化学
水文学(农业)
海洋学
地质学
气候变化
土壤科学
化学
生态学
生态系统
地理
复合材料
有机化学
生物
古生物学
岩土工程
材料科学
地图学
复合数
作者
Sanjeev Dasari,Mark H. Garnett,Robert Hilton
出处
期刊:PNAS nexus
[Oxford University Press]
日期:2024-03-28
卷期号:3 (4)
标识
DOI:10.1093/pnasnexus/pgae134
摘要
The Canadian Arctic is warming at an unprecedented rate. Warming-induced permafrost thaw can lead to mobilization of aged carbon from stores in soils and rocks. Tracking the carbon pools supplied to surrounding river networks provides insight on pathways and processes of greenhouse gas release. Here, we investigated the dual-carbon isotopic characteristics of the dissolved inorganic carbon (DIC) pool in the main stem and tributaries of the Mackenzie River system. The radiocarbon (14C) activity of DIC shows export of "old" carbon (2,380 ± 1,040 14C years BP on average) occurred during summer in sampling years. The stable isotope composition of river DIC implicates degassing of aged carbon as CO2 from riverine tributaries during transport to the delta; however, information on potential drivers and fluxes are still lacking. Accounting for stable isotope fractionation during CO2 loss, we show that a large proportion of this aged carbon (60 ± 10%) may have been sourced from biospheric organic carbon oxidation, with other inputs from carbonate weathering pathways and atmospheric exchange. The findings highlight hydrologically connected waters as viable pathways for mobilization of aged carbon pools from Arctic permafrost soils.
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