Collaborative Research: NSFGEO-NERC: A Thermodynamic Chemical Speciation Model for the Oceans, Seas and Estuaries

由于二氧化碳在海水中的溶解增加而导致的海洋酸化，以及累积应激源(包括酸化、污染、变暖和缺氧)的影响是海洋研究的首要任务。科学进步需要在全球范围内进行准确和一致的测量，以监测和了解目前的影响，并建立模型，以评估未来的补救方案和方法。观测科学家和模型师的工作与需要准确了解无机碳酸盐体系的化学形态、pH以及自然水域和用于仪器校准的参考材料和溶液中的营养和污染痕量金属有关。在这项由美国和英国的研究人员合作的项目中，一个科学家团队将致力于创建一种彻底更新的建模工具，以确定海水的详细化学成分或“物种形成”。研究人员建议，通过在计算溶质和水活度的匹泽方程的基础上建立物种形成模型，使海洋科学家测量、解释和预测不同组成的自然水域中的化学形态和pH值的能力发生阶段性变化。这种方法在地球化学领域有着长期的成功记录。这些方程是基于这样一个概念，即溶解溶质物种对和三态之间的相互作用控制着活性。这些相互作用的参数值是从溶液性质的广泛测量中确定的。该项目的工作将包括：测量活动和热容量，并利用最近的文献数据改进和测试该模型；对该模型进行计算机编码和验证，并制定方法以量化模型预测的物种形成中的不确定性与基本测量中的不确定性之间的关系；与国际海洋学家接触，帮助为具体应用设计实用的物种形成模拟工具和相关指导。该项目的结果将是一个经过严格评估的自然水域热力学模型，该模型包含(以任何比例)海水的主要和次要离子、与海水有关的pH缓冲液以及痕量金属铁、锌、铜和镉，将通过项目网站向更广泛的社区提供。学术受益者将是化学海洋学家、水生科学家和在以下领域工作的其他人：海洋酸化，包括极地卤水(在季节性冰中)；孔隙水化学成岩反应；古海洋学；海水等盐水溶液pH值的计量学。一名博士后研究人员将通过该项目得到支持和培训。

Ocean acidification due to increasing dissolution of carbon dioxide in seawater, and the effects of cumulative stressors (including acidification, pollution, warming, and anoxia) are among the top priorities for ocean research. Scientific progress requires accurate and consistent measurements across the globe to monitor and understand present effects, and modelling to evaluate future scenarios and methods of remediation. The work of observational scientists and modelers is linked by the need for an accurate knowledge of the chemical speciation of the inorganic carbonate system, pH, and nutrient and contaminate trace metals, in both natural waters and the reference materials and solutions used for instrument calibration. In this collaborative project between investigators in the U.S. and the United Kingdom, a team of scientists will work to create a thoroughly updated modeling tool for determining the detailed chemical composition, or "speciation," of seawater. The investigators propose to create a step change in the capability of marine scientists to measure, interpret, and predict chemical speciation and pH in natural waters of varying composition by creating a speciation model based upon the Pitzer equations for the calculation of solute and water activities. The approach has a long track record of success in geochemistry. The equations are based upon the concept that interactions between pairs and triplets of dissolved solute species control activities. The values of the parameters for these interactions are determined from a wide range of measurements of solution properties. Work in this project will include measuring activities and heat capacities, and using recent literature data, to improve and test the model; the computer coding and validation of the model and the development of methods to quantify the relationship between uncertainties in model-predicted speciation and those in the underlying measurements; and engagement with oceanographers internationally to help design practical speciation modelling tools and associated guidance for specific applications. The result of this project will be a critically-evaluated thermodynamic model of natural waters containing (in any proportion) the major and minor ions of seawater, seawater-related pH buffers, and the trace metals iron, zinc, copper, and cadmium, to be made available to the wider community through a project web site. The academic beneficiaries will be chemical oceanographers, aquatic scientists, and others working in the following areas: ocean acidification including polar brines (in seasonal ice); pore water chemistry diagenetic reactions; paleoceanography; metrology of pH in saline solutions such as seawater. A postdoctoral researcher will be supported and trained through this project.