Arctic lakes are poised for substantial changes to their carbon (C) cycles in the near future. Autochthonous processes in lakes which consume inorganic C and create biomass that can be sequestered in sediments are accompanied by allochthonous inputs of organic matter from the surrounding watershed. Both C sources can be mineralized and degassed as CO₂, but also become recalcitrant and accumulate in pelagic waters. Using stable carbon isotope (δ¹³C) values and elemental ratios as geochemical proxies, we investigated diverse organic matter sources to lakes located across a hydro‐climatic gradient in Southwest Greenland. Particulate organic matter (POM) and sediments were clearly of autochthonous algal origin, while dissolved organic matter (DOM) was a mix between autochthonous macrophytes and allochthonous watershed sources. Our results imply that a warmer and drier Arctic will lead to decoupled C pools: a water column dominated by increasingly autochthonous, macrophytic DOM, and sediments dominated by autochthonous algal POM.

中文翻译：

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稳定的同位素揭示了北极水气候梯度上的独立碳库：对温暖和干燥条件下碳命运的影响

北极湖泊将在不久的将来对其碳（C）循环进行重大改变。在湖泊中，消耗无机碳并产生可以隔离在沉积物中的生物量的自发过程伴随着来自周围流域的有机物的异源输入。两种碳源都可以被矿化和脱气为CO ₂，但也变得顽强并在浮游水中积聚。采用稳定碳同位素（δ ¹³C）值和元素比率作为地球化学替代物，我们调查了西南格陵兰岛上跨水气候梯度的湖泊的各种有机质来源。颗粒有机物（POM）和沉积物显然是自生的藻类起源，而溶解的有机物（DOM）是自生的大型植物与异源的集水区之间的混合物。我们的结果表明，北极干热会导致C池解耦：水柱被越来越多的自生的大型植物性DOM支配，而沉积物则被自生的藻类POM支配。