Chemodiversity of dissolved organic matter in lakes driven by climate and hydrology
Chemodiversity of dissolved organic matter in lakes driven by climate and hydrology
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DOI：
10.1038/ncomms4804
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发表时间：
2014-05-01
影响因子：
16.6
通讯作者：
Tranvik, Lars J.
中科院分区：
文献类型：
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作者：
Kellerman, Anne M.;Dittmar, Thorsten;Tranvik, Lars J.
尽管湖泊的大陆覆盖范围很小，但它们是碳循环的热点，这主要是由于陆地来源的溶解有机物（DOM）的处理。由于 DOM 是包含微生物和物理化学反应性梯度的异质化合物的混合物，因此在分子水平上影响 DOM 加工的因素以及由此产生的 DOM 组成模式尚不清楚。在这里，我们使用超高分辨率质谱明确地识别了瑞典 120 个湖泊中的 4,032 个分子式，表明 DOM 的分子组成是由降水、水停留时间和温度决定的。随着停留时间的增加，来自陆地的 DOM 会选择性地损失，温度升高会增强含氮化合物的产生。利用生物多样性概念，我们表明 DOM 的分子多样性或化学多样性随着 DOM 和养分浓度的增加而增加。观察到的分子水平模式表明，随着气候变得湿润，来自陆地的 DOM 将在湖泊中变得更加普遍。
Despite the small continental coverage of lakes, they are hotspots of carbon cycling, largely due to the processing of terrestrially derived dissolved organic matter (DOM). As DOM is an amalgam of heterogeneous compounds comprising gradients of microbial and physicochemical reactivity, the factors influencing DOM processing at the molecular level and the resulting patterns in DOM composition are not well understood. Here we show, using ultrahigh-resolution mass spectrometry to unambiguously identify 4,032 molecular formulae in 120 lakes across Sweden, that the molecular composition of DOM is shaped by precipitation, water residence time and temperature. Terrestrially derived DOM is selectively lost as residence time increases, with warmer temperatures enhancing the production of nitrogen-containing compounds. Using biodiversity concepts, we show that the molecular diversity of DOM, or chemodiversity, increases with DOM and nutrient concentrations. The observed molecular-level patterns indicate that terrestrially derived DOM will become more prevalent in lakes as climate gets wetter.