Penetration of solar ultraviolet radiation into New Zealand lakes: influence of dissolved organic carbon and catchment vegetation
Penetration of solar ultraviolet radiation into New Zealand lakes: influence of dissolved organic carbon and catchment vegetation
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DOI：
10.1007/s102010170003
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发表时间：
2001-08
期刊：
影响因子：
1.6
通讯作者：
R. Rae;C. Howard-Williams;Ian Hawes;A. Schwarz;W. Vincent
中科院分区：
文献类型：
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作者：
R. Rae;C. Howard-Williams;Ian Hawes;A. Schwarz;W. Vincent
1996年夏天，对新西兰南岛的11个湖泊进行了采样。获得了4个波长的紫外线辐射(UVR)和光合作用有效辐射(PAR)的水柱剖面，并分析了溶解有机碳(DOC)浓度、总悬浮固体(TSS)和集水区植被(包括森林和天然草地)。研究了UVR向下衰减系数(Kd)和湖水透明度(1/Kd)与这些变量的关系。与世界其他地区一致，DOC浓度和与DOC相关的变量是UVR渗透率的最佳预测因子。根据我们的数据集，我们使用文献中的公式计算了UVR/PAR辐照度的水柱积分(RI)的比率。当DOC浓度低于4g m−3时，RI逐渐增加，表明湖泊对紫外线变得越来越透明。我们还对UVR在380 nm处的发色溶解有机物(CDOM)吸收与DOC浓度进行了归一化处理，发现单位DOC对UVR的吸收能力随着集水区森林比例的增加而增加。这表明，在决定湖水对UVR的透明度时，不仅DOC浓度，而且DOC类型或组成也是重要的，并且DOC的质量差异取决于湖泊集水区存在的植被类型和数量。
Eleven lakes in the South Island of New Zealand were sampled in summer 1996. Water column profiles of ultraviolet radiation (UVR) at four wavelengths and photosynthetically available radiation (PAR) were obtained, along with analyses of dissolved organic carbon (DOC) concentration, total suspended solids (TSS), and catchment vegetation, including forest and natural grassland. Downward attenuation coefficients (Kd) and lake water transparency (1/Kd) for UVR were examined in relation to these variables. Consistent with other regions of the world, DOC concentration and variables related to DOC were the best predictors of UVR penetration. With our data set, we calculated ratios of water column integrals (RI) of UVR/PAR irradiance, using equations from the literature. At DOC concentrations below 4 g m−3, a progressive increase in RI shows that lakes become increasingly transparent to UVR. We also normalized chromophoric dissolved organic matter (CDOM) absorption of UVR at 380 nm (a380) to DOC concentration and found that the UVR-absorbing capacity per unit DOC increases with increasing percentage of forest in the catchment area. This indicates that not only DOC concentration but also DOC type or composition is important in determining the transparency of lake water to UVR, and that qualitative differences in DOC are dictated by the type and amount of vegetation present in the lake's catchment area.