Controls on the Stable Isotope Chemistry & Major Ion Fluxes Between Lakes & Groundwaters in a Northern Hardwood, Glaciated Terrain: Short-Term and Long-Term Conseque

要求提供资金，利用稳定同位素和主要离子化学方法进行湖泊-地下水相互作用的研究。重点将放在del O18的同位素变化和主要离子化学（Ca, Mg, Na， K, Cl, SO4，碱度和pH）在一些湖泊，它们周围的地下水，和当地大气降水。研究区域将从现有的NSF-LTER北温带湖泊研究地点扩展，该地点在过去10年中进行了广泛的生物，生态，地球化学和气候学测量，位于北部阔叶林，冰川地形，湖泊丰富，排水一体化程度低的地区。同位素数据将用于计算湖泊的水文收支，并根据NSF-LTER湖泊研究开发的方法建立地下水同位素化学的区域梯度。利用这些基于同位素的质量平衡估算，我们将：a)估算湖泊输入水的平均成分；B)了解湖泊内部循环与外部湖泊溶质（尤其是二氧化硅）负载的相对作用；c)确定受冬季道路盐严重Cl和Na污染的湖泊的自然溶质负荷；D)根据对决定输入水的化学性质的矿物学相的观察来模拟水的组成；e)预测湖泊和地下水因短期和长期气候变化而发生的化学和水文变化。我们的研究对温带地区广阔的年轻冰川地形的湖泊和地下水化学的演变和变化具有重要意义，并有助于我们区分湖泊地球化学循环与外部湖泊负荷的相对重要性。根据目前进出湖泊的水通量和相关的溶质负荷的知识，我们打算模拟湖泊/地下水化学对短期和长期气候变化的响应，并估计这一重要地区对这种变化的敏感性。

Funding is requested to conduct studies of lake-groundwater interaction using stable isotopic and major ion chemical approaches. Emphasis will be on isotopic variation in del O18 and major ion chemistry (Ca, Mg, Na, K, Cl, SO4, Alkalinity, and pH) in a number of lakes, their surrounding groundwaters, and local atmospheric precipitation. The research area will extend from the existing NSF-LTER North Temperate Lakes research site, a location where extensive biologic, ecological, geochemical, and climatological measurements have been made over the past 10 years, an area in a northern hardwood forest, glaciated terrain with abundant lakes and little drainage integration. Isotope data will be used to calculate hydrologic budgets for lakes and to establish regional gradient in groundwater isotope chemistry according to methods developed for the NSF-LTER lake study. Using these isotope based mass balance estimates we will: a) estimate the average composition of input waters to the lakes; b) understand of the relative role of in lake cycling vs. external lake loading of solutes (especially silica); c) determine natural solute loads to lakes that suffer significant Cl and Na contamination from winter road salt; d) model the composition of waters based on observation of the mineralogic phases that determine the chemistry of the input waters; and e) predict chemical and hydrologic changes that would occur in lakes and groundwaters in response to short-term and long- term climate change. Our studies have implications on the evolution and variations in lake and groundwater chemistry in a broad region of youthful glaciated terrains in temperate regions, and should help us in differentiate the relative importance in lake geochemical cycling vs. external lake loading. From the knowledge of present fluxes of waters to and from lakes and the associated solute loading we intend to model the response of the lake/groundwater chemistry to short-term and long-term variation in climate, and estimate the sensitivity of this important region to such changes.