New insights into the source of decadal increases of dissolved organic matter in acid-sensitive lakes of the northeastern United States.
New insights into the source of decadal increases of dissolved organic matter in acid-sensitive lakes of the northeastern United States.
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DOI：
10.1021/es204321x
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发表时间：
2012-02
影响因子：
11.4
通讯作者：
M. SanClements;G. Oelsner;D. McKnight;J. Stoddard;S. Nelson
中科院分区：
文献类型：
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作者：
M. SanClements;G. Oelsner;D. McKnight;J. Stoddard;S. Nelson
在过去的几十年里，美国东北部的SO（4）（2-）沉积量有所减少。因此，湖泊和溪流中的SO（4）（2-）浓度也有所下降，许多地表水体的酸性也有所降低。在同一时期，许多湖泊和溪流中溶解有机碳（DOC）浓度同时增加。我们使用荧光光谱来表征溶解有机物（DOM）的质量存档样本从9个酸敏感的湖泊在缅因州收集1993年至2009年，并确定增加DOM贡献湖泊主要来自凋落物和土壤。所有五个具有增加DOC趋势的湖泊都表现出显著的减少（即，荧光指数（FI）的变化趋势与SO（4）（2-）之间存在显著的正相关关系。这项研究使用陆地DOM的化学特征来支持这一假设，即湖泊和溪流中DOC浓度的增加是由大面积景观中酸沉降下降和土壤有机质溶解度增加所驱动的。
The last several decades have seen decreases in SO(4)(2-) deposition across the northeastern United States. As a result, SO(4)(2-) concentrations in lakes and streams have also decreased and many surface water bodies have become less acidic. During the same time period, there has been a concurrent increase in dissolved organic carbon (DOC) concentrations in many lakes and streams. We used fluorescence spectroscopy to characterize the dissolved organic matter (DOM) quality of archived samples from nine acid-sensitive lakes in Maine collected between 1993 and 2009, and determined that increased DOM contributions to lakes were primarily derived from litter and soil. All five lakes with increasing DOC trends demonstrated significant decreasing (i.e., more terrestrial) trends in fluorescence index (FI) and significant positive correlations between SO(4)(2-) and FI. This study used the chemical signature of terrestrial DOM to support the hypothesis that increased DOC concentrations in lakes and streams are driven by declining acid deposition and increased solubility of soil organic matter across a large area of the landscape.