Timescales of Geochemical and Isotopic Transport in Natural Waters

寻求9814621Criss资金，以开发和测试来自岩溶和非岩溶流域的天然水中溶质和同位素运移的新模型。这一模型有可能量化运输的时间尺度，而不需要特别假设地下水和地表水成分的混合。在这个数学模型中，基于扩散理论，风暴事件被视为引发一系列复杂的地球化学反应和物理反应的“三角洲函数”。输运方程很容易转化为线性形式，其截距准确地追溯风暴事件的时间，其斜率揭示了每一种地球化学组分的输运时间常数。我们的基本概念是研究由自然过程提供的扰动的自然系统。在某种意义上，这种方法类似于地震学中使用地震来提取地下结构的信息。我们建议研究地表溪流和泉水对风暴事件的物理、地球化学和同位素响应，目的是确定复杂自然响应的时间尺度。我们的初步数据显示，不同的参数(径流、离子浓度、营养盐、沉积物、氧同位素等)。行为在性质上相似，可以用模型来解释，但在共同定义自然系统响应的自然参数之间，时间尺度差别很大。我们建议对这一新模型进行几个严格的测试。首先，将回顾在线水文资料，以检验该模型在岩溶和非岩溶流域的应用。其次，将从密苏里州东部未蓄水的Meramec盆地收集地球化学和同位素数据。由位于Meramec河上的华盛顿大学泰森研究中心提供的通道，将允许以准确解析时间尺度所需的时间间隔进行密集采样。一旦建立了时间尺度，我们就可以开始识别反应(溶解度、离子交换、吸附、生物吸收等)的工作。控制每种成分的可获得性。我们提出的新方法似乎同时适用于不同的地球化学、物理和同位素成分，并具有利用自然事件解决自然系统复杂性的独特潜力。

9814621Criss Funds are sought to develop and test a new model of solute and isotopic transport in natural waters from karst and non-karst watersheds. This model has the potential to quantify the timescales of transport without ad hoc assumptions about mixing of groundwater and surface water components. In this mathematical model, based on diffusion theory, storm events are treated as "delta functions" that induce a complex series of geochemical and physical responses. The transport equations are readily transformed into linear versions whose intercepts accurately retrodict the timing of the storm events, and whose slopes reveal the time constants for transport of each geochemical constituent. Our basic concept is to study the natural system with perturbations provided by natural processes. In a sense this approach is analogous to the use of earthquakes in seismology to extract information about subsurface structure.We propose to examine the physical, geochemical and isotopic response of surface streams and springs to storm events with the goal of determining the timescales of complex natural responses. Our preliminary data show that different parameters (streamflow, ionic concentrations, nutrients, sediment, oxygen isotopes, etc.) behave in a qualitatively similar manner, explicable by the model, but that the timescales vary greatly among the natural parameters that collectively define the response of the natural system. We propose several rigorous tests of this new model. First, a review will be made of on-line hydrograph data to test the model in karst and non-karst watersheds. Second, geochemical and isotopic data will be collected from the unimpounded Meramec Basin in eastern Missouri. Access provided by Washington University's Tyson Research Center, located on the Meramec river, will allow intensive sampling at the time intervals required to resolve timescales accurately. Once timescales are established we can begin the work of identifying the reactions (solubility, ion exchange, adsorption, biological uptake, etc.) that control the availability of each constituent. The new approach we propose appears to be applicable simultaneously to diverse geochemical, physical, and isotopic constituents, and has the unique potential to resolve the complexity of natural systems using natural events.