Variability in organic carbon reactivity across lake residence time and trophic gradients
Variability in organic carbon reactivity across lake residence time and trophic gradients
复制标题
DOI：
10.1038/ngeo3051
复制
发表时间：
2017-11-01
影响因子：
18.3
通讯作者：
Kothawala, Dolly N.
中科院分区：
文献类型：
--
作者：
Evans, Chris D.;Futter, Martyn N.;Kothawala, Dolly N.
溶解有机碳从陆地向海洋的迁移是全球碳循环的重要动态组成部分。内陆沃茨是有机物通过生物和光化学过程周转的热点，并介导陆地、海洋和大气之间的碳转移。然而，预测溶解的有机碳反应性仍然存在问题。在这里，我们提出了原位溶解的有机碳预算数据，从82个主要是欧洲和北美水体不同的营养浓度和水的停留时间从一个星期到700年。我们发现，营养状态强烈调节水体是否作为净溶解有机碳源或汇，溶解有机碳的生产和消费率可以预测从水停留时间。我们的研究结果表明，在水体中快速光驱动的去除具有较短的水停留时间的主导作用，而在水体中具有较长的停留时间，较慢的生物生产和消费过程是占主导地位的，并相互抵消。富营养化导致湖泊从溶解有机碳的汇转变为源。我们的结论是，溶解有机碳处理和相关的CO2排放量在内陆沃茨的速度和位置可能是错误的，在全球碳预算，如果时间和空间的反应性梯度不占。
The transport of dissolved organic carbon from land to ocean is a large dynamic component of the global carbon cycle. Inland waters are hotspots for organic matter turnover, via both biological and photochemical processes, and mediate carbon transfer between land, oceans and atmosphere. However, predicting dissolved organic carbon reactivity remains problematic. Here we present in situ dissolved organic carbon budget data from 82 predominantly European and North American water bodies with varying nutrient concentrations and water residence times ranging from one week to 700 years. We find that trophic status strongly regulates whether water bodies act as net dissolved organic carbon sources or sinks, and that rates of both dissolved organic carbon production and consumption can be predicted from water residence time. Our results suggest a dominant role of rapid light-driven removal in water bodies with a short water residence time, whereas in water bodies with longer residence times, slower biotic production and consumption processes are dominant and counterbalance one another. Eutrophication caused lakes to transition from sinks to sources of dissolved organic carbon. We conclude that rates and locations of dissolved organic carbon processing and associated CO2 emissions in inland waters may be misrepresented in global carbon budgets if temporal and spatial reactivity gradients are not accounted for.