Jones M L M, Reynolds B, Brittain S A, Norris D A, Rhind P M, Jones R E
Centre for Ecology and Hydrology Bangor, Orton Building, Deiniol Road, Bangor, Gwynedd LL57 2UP, UK.
Sci Total Environ. 2006 Dec 15;372(1):266-77. doi: 10.1016/j.scitotenv.2006.08.040. Epub 2006 Oct 24.
Dune slacks are a species-rich habitat controlled largely by water chemistry and fluctuations in groundwater. Changes in water chemistry and water table level were analysed in 8 piezometers and 15 ephemeral surface water locations at a large UK dune system over a 12-month period. Total nitrogen concentrations in groundwater varied from 0.27-8.21 mg N L(-1), where dissolved organic nitrogen was dominant at the low nitrogen locations and nitrate was dominant at the high nitrogen locations. Principal components analysis of the water chemistry suggests at least four chemically distinct groundwater signatures. Water levels showed strong temporal heterogeneity. Comparisons of water levels with antecedent rainfall identified a component of year-round groundwater feed and differing seasonal responses overlain by a complex series of lags. In summer, there were lags of four, six and seven months with an additional rapid peaky response to daily rainfall with a one-day lag. In winter, water levels were strongly influenced by exogenous groundwater supply, but again exhibited multiple lags. This study shows that local variations in water chemistry and in hydrological regime can be more complicated than previously thought, with clear implications for optimum management of these high priority habitats for conservation.
沙丘洼地是一个物种丰富的栖息地，主要受水化学和地下水位波动的控制。在英国一个大型沙丘系统的8个测压管和15个季节性地表水位置，对12个月期间的水化学和地下水位变化进行了分析。地下水中的总氮浓度在0.27 - 8.21毫克氮/升之间变化，在低氮位置溶解有机氮占主导，在高氮位置硝酸盐占主导。水化学的主成分分析表明至少有四种化学性质不同的地下水特征。水位显示出强烈的时间异质性。将水位与前期降雨量进行比较，确定了全年地下水补给的一个组成部分以及不同的季节性响应，并叠加了一系列复杂的滞后现象。在夏季，存在四个、六个和七个月的滞后，对每日降雨还有一个一天滞后的额外快速尖峰响应。在冬季，水位受到外源地下水供应的强烈影响，但同样表现出多重滞后。这项研究表明，水化学和水文状况的局部变化可能比以前认为的更为复杂，这对这些高度优先保护栖息地的最佳管理具有明确的意义。
