Dissipation of Thermal and Chemical Disequilibrium in Hot Springs

温泉是以热和化学不平衡为特征的环境。本研究的目的是确定热和化学不平衡消散的非生物过程的速率和机制。这项研究的目的是通过对黄石国家公园和拉森火山国家公园的温泉进行实地研究，并辅以一些实验室实验来获得这些速率。当水从温泉孔或温泉池流出时，发生了四种相互关联的非生物过程。它们是a)流体流动b)冷却，c)气体传递（例如，气体中的O2， H2， CO2和H2S放气），以及d)水中的化学反应（例如，曲华沉积和硫化氢氧化）。研究人员已经制定了一项研究策略，通过详细测量排水系统中的流动状态（线速度和湍流测量），结合详细的温度测量来获得冷却速率，并通过化学分析来获得水在流动过程中的化学演变，从而获得这些过程的速率。化学分析包括测定溶解气体（He、H2、Ar、O2、CO2和H2S）的浓度和溶解的主要离子种类。由温度分布和浓度分布可以推导出传热系数和气体传递系数。由于气体传递系数的确定是至关重要的，因此提出了一系列的实验室实验，其中CO2的气体交换系数是通过在一个简单的人工通道中进行脱气实验得出的，该通道的流态与黄石公园研究的排水相似。为了使这些实验简单，他们将在室温下进行，但气体传递理论已经足够发达，可以外推到更高的温度。实验室实验将由本科生进行。

SchoonenEAR-0073963Hot springs are environments characterized by thermal and chemical disequilibrium. The purpose of the proposed study is to determine the rates and mechanisms of abiotic processes by which the thermal and chemical disequilibrium is dissipated. The objective of this study is to obtain these rates through field studies of hot springs in Yellowstone National Park and possibly Lassen Volcanic National Park, complemented by a few laboratory experiments. As water flows away from the orifice or pool of hot spring, four types of interrelated abiotic processes take place. These are a) fluid flow b) cooling, c) gas transfer (e.g., O2 in gassing, H2, CO2 and H2S outgassing) , and d) chemical reactions in the water (e.g., travetine deposition, and hydrogen sulfide oxidation). A research strategy has been developed to obtain rates of these processes through detailed measurements of flow regimes (linear velocity and a measure of turbulence) in the drainages coupled with detailed temperature measurements to obtain cooling rates and chemical analyses to obtain the chemical evolution of the water as it flows away. The chemical analyses involve a determination of the concentration of dissolved gases (He, H2, Ar, O2, CO2, and H2S) and dissolved major ionic species. From the temperature profiles and concentration profiles the heat transfer coefficients and gas transfer coefficients can be derived. Because the determination of the gas transfer coefficients is crucial, a series of laboratory experiments is proposed in which the gas exchange coefficient of CO2 is derived by conducting a degassing experiment in a simple artificial channel with a flow regime similar to the drainages studied in Yellowstone. To keep these experiments simple they will be conducted at room temperature, but gas transfer theory is sufficiently well developed to allow extrapolation to higher temperature. The laboratory experiments will be conducted by undergraduate students.