Scales of Hydrologic Transients in Holocene Lake Records: Ostracodes, Groundwater Flow, and Paleochemistry Collaborative Research

这项建议解决了确定地下水补给的湖泊在全新世期间对气候变化的水化学反应的问题。我们打算确定地下水和地表水对明尼苏达州格兰特公司Elk Lake的相对重要性。我们将检查和比较从介形虫(甲壳纲)物种分布、介形虫外壳化学以及描述水化学反应和地下水流动的模型中获得的信息。拟议的研究将提供一种独立的手段来确定湖泊在过去气候变化的特定时期如何与地下水相互作用，以及洞察湖泊-地下水系统如何对未来的气候变化做出反应。我们的方法将是1)确定目前流入麋鹿湖的地下水来源(S)；2)从湖泊中恢复完整的全新世岩心；3)利用介形虫物种分布、微量元素和稳定同位素分析重建溶质历史；4)检验关于全新世地下水输入和生成的湖泊化学的两个假说。这项研究将为区域地表水文学响应气候变化提供一条新的途径，并在水文学和气候学领域具有广泛的应用。研究结果对关注地表水-地下水相互作用的水文学家和对气候模型验证和气候引起的水文变化预测感兴趣的气候学家具有实用价值。

This proposal addresses the problem of determining the hydrochemical response of a groundwater-fed lake to climate change over Holocene time. We intend to determine the relative importance of ground water and surface water input to Elk Lake, Grant Co., Minnesota. We will examine and compare information obtained from ostracode (Crustacea) species distributions, ostracode shell chemistry, and models that describe hydrochemical reactions and groundwater flow. The proposed research will provide an independent means of determining how a lake interacted with groundwater during specific times of past climate change, as well as insight into how lake-groundwater systems can react to future climate change. Our approach will be 1) define the ground water source(s) flowing into Elk Lake at present; 2) recover a complete Holocene core from the lake; 3) reconstruct the solute history using ostracode species distributions, trace-elements, and stable isotope analyses; and 4) test two hypotheses concerning the groundwater input and resultant lake chemistry through Holocene time. This study will provide a new way of reconstructing regional changes in surface hydrology as it responds to climate change and has wide application to the field of hydrology and climatology. The results should be of practical value to hydrologists concerned with surface water-groundwater interactions, and to climatologists interested in climate model validation and forecasting of climate- induced hydrologic changes.