Hydrology controls dissolved organic matter export and composition in an Alpine stream and its hyporheic zone.
Hydrology controls dissolved organic matter export and composition in an Alpine stream and its hyporheic zone.
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DOI：
10.1002/lno.10232
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发表时间：
2016-03
影响因子：
4.5
通讯作者：
Battin TJ
中科院分区：
文献类型：
--
作者：
Fasching C;Ulseth AJ;Schelker J;Steniczka G;Battin TJ
溪流和河流将溶解有机物 (DOM) 从陆地环境输送到下游生态系统。鉴于气候和全球变化，了解 DOM 浓度和组成的时间动态及其从源头到更大的下游生态系统的输出通量至关重要。我们根据昼夜采样设计对阿尔卑斯山源头水流进行了 3 年的 DOM 浓度和成分监测。我们发现水文变异性可以控制 DOM 组成以及溪流和潜流区 DOM 动态的耦合。高流量事件增加了来自陆地来源的 DOM 输入（如腐殖酸和类黄腐荧光的贡献所示），而夏季基流增强了 DOM 的本土印记。 DOM 组成的昼夜和季节模式可能是由与温度和光合有效辐射 (PAR) 相关的生物过程引起的。洪水经常中断 DOM 的昼夜和季节性模式，导致河水和潜流水 DOM 组成脱钩，并将芳香族和腐殖质类 DOM 输送到河水中。因此，从光学特性可以看出，DOM 输出通量主要来自陆源。我们的研究强调了水文和季节动态与阿尔卑斯山源头溪流中 DOM 的起源、组成和通量的相关性。
Streams and rivers transport dissolved organic matter (DOM) from the terrestrial environment to downstream ecosystems. In light of climate and global change it is crucial to understand the temporal dynamics of DOM concentration and composition, and its export fluxes from headwaters to larger downstream ecosystems. We monitored DOM concentration and composition based on a diurnal sampling design for 3 years in an Alpine headwater stream. We found hydrologic variability to control DOM composition and the coupling of DOM dynamics in the streamwater and the hyporheic zone. High‐flow events increased DOM inputs from terrestrial sources (as indicated by the contributions of humic‐ and fulvic‐like fluorescence), while summer baseflow enhanced the autochthonous imprint of DOM. Diurnal and seasonal patterns of DOM composition were likely induced by biological processes linked to temperature and photosynthetic active radiation (PAR). Floods frequently interrupted diurnal and seasonal patterns of DOM, which led to a decoupling of streamwater and hyporheic water DOM composition and delivery of aromatic and humic‐like DOM to the streamwater. Accordingly, DOM export fluxes were largely of terrigenous origin as indicated by optical properties. Our study highlights the relevance of hydrologic and seasonal dynamics for the origin, composition and fluxes of DOM in an Alpine headwater stream.