The attentuation of solar UV radiation in lakes and the role of dissolved organic carbon
The attentuation of solar UV radiation in lakes and the role of dissolved organic carbon
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DOI：
10.4319/lo.1995.40.8.1381
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发表时间：
1995-12-01
影响因子：
4.5
通讯作者：
Queimalinos, C
中科院分区：
文献类型：
--
作者：
Morris, DP;Zagarese, H;Queimalinos, C
在阿拉斯加、科罗拉多州、宾夕法尼亚州和阿根廷巴里洛切地区的65个湖泊混合层中测量了太阳紫外线辐射（UVR）（305、320、340、380 nm和PAR）的漫射衰减系数（K-d），同时收集了湖泊混合层水的综合样品，并采用多变量方法对K-d进行了建模，其中包括一些光学和化学变量。在湖泊之间观察到透明度有很大差异。UV-B辐射的衰减深度（z(1%)）范围从几厘米到10米。在一些典型的高海拔生态系统的浅、低DOC（溶解有机C）湖泊中，大量的UVR通量贯穿整个水柱。在较深、DOC浓度较低的湖泊中，混合层中有相当大比例的UVR通量较高。湖间K-d变化（87% -96%）主要由DOC浓度差异解释，DOC浓度对溶解吸光度有强烈影响。平均而言，溶解吸光度占原位测量K-d的33% （PAR）至68% （305 nm）。在整个太阳UV-A和UV-B范围内，K-d的最佳估算方法是仅基于DOC浓度的单变量功率模型。还提出了将吸收系数与K-d联系起来的模型。这些模型可以与档案DOC或彩色数据一起使用，以提供湖泊紫外线透明度的大致估计。
Diffuse attenuation coefficients (K-d) for solar UV radiation (UVR) (305, 320, 340, 380 nm, and PAR) were measured in the mixed layer of 65 lake sites in Alaska, Colorado, and Pennsylvania and the Bariloche region of Argentina, Integrated mixed layer samples of lake water were concurrently collected, and a multivariate approach was used to model K-d with a number of optical and chemical variables.Substantial variation in transparency was observed among lakes. Attenuation depths (z(1%)) for UV-B radiation ranged from several centimeters to >10 m. In some shallow, low DOC (dissolved organic C) lakes typical of high elevation ecosystems, substantial fluxes of UVR penetrated the entire water column. In deeper lakes with low DOC concentrations, high fluxes of UVR were found in a significant proportion of the mixed layer. Much of the among-lake variation in K-d (87-96%) was explained by differences in DOC concentration, which strongly influenced dissolved absorbance. On average, dissolved absorbance accounted for between 33% (for PAR) and 68% (for 305 nm) of K-d measured in situ, Throughout the solar UV-A and UV-B range, K-d was best estimated with a univariate power model based solely on DOC concentration. Models are also presented that relate absorption coefficients to K-d. These models can be used with archival DOC or color data to provide approximate estimates of UV transparency of lakes.