Effects of upstream lakes on dissolved organic matter in streams
Effects of upstream lakes on dissolved organic matter in streams
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DOI：
10.4319/lo.2007.52.1.0060
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发表时间：
2007-01
影响因子：
4.5
通讯作者：
James H. Larson;P. Frost;Zhiyu Zheng;C. Johnston;S. Bridgham;D. Lodge;G. Lamberti
中科院分区：
文献类型：
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作者：
James H. Larson;P. Frost;Zhiyu Zheng;C. Johnston;S. Bridgham;D. Lodge;G. Lamberti
我们研究了上游湖泊对溶解有机物（DOM）的数量和紫外线（UV）辐射的吸收率在密歇根州北方的流的影响。我们评估了DOM浓度和吸收率在15个流与上游湖泊和17个流没有上游湖泊位于同一地理区域在2003年5月和8月。此外，我们估计流域土地覆盖和形态，以评估其他景观变量可以解释两种流类型之间的DOM差异的可能性。溶解有机碳的浓度，其UVB吸光度，其摩尔吸光度（每单位碳的吸光度）都显着低于在流与上游湖泊比流没有湖泊。上游流域指标和流DOM属性之间存在较强的预测关系，但因季节和上游湖泊的存在而异。DOM量和紫外线吸收能力与不同的流域指标有关，DOM量与陆地流域指标密切相关，而紫外线吸收能力与水面面积百分比密切相关。上游湖泊强烈影响下游DOM潜在的，因为它们的水停留时间长，这可能会增加DOM处理的机会。上游湖泊代表了一个强大的景观流DOM属性的预测，不直接绑定到陆地DOM的来源和处理。
We examined the effects of upstream lakes on dissolved organic matter (DOM) quantity and the absorbance of ultraviolet (UV) radiation in the streams of northern Michigan. We assessed DOM concentration and absorbance in 15 streams with upstream lakes and 17 streams without upstream lakes located in the same geographic region in May and August 2003. In addition, we estimated watershed land cover and morphology to assess the possibility that other landscape variables could account for DOM differences between the two stream types. The concentration of dissolved organic carbon, its UVB absorbance, and its molar absorbtivity (absorbance per unit carbon) were all significantly lower in streams with upstream lakes than in streams with no lakes. Strong predictive relationships existed between upstream watershed metrics and stream DOM properties, but varied by season and the presence of upstream lakes. DOM quantity and UV‐absorbing ability were related to different watershed metrics, with DOM quantity being strongly related to terrestrial watershed metrics, whereas UV‐absorbing ability was most strongly related to percent water surface area. Upstream lakes strongly influence downstream DOM potentially because of their long water residence times, which could increase opportunities for DOM processing. Upstream lakes represent a strong landscape predictor of stream DOM properties that is not directly tied to terrestrial DOM sources and processing.