The carbonate system at sub-zero temperatures and high ionic strength.

我们对海洋中碳的地球化学循环的理解已经发生了革命性的变化，因为我们有能力分析通过气体交换和含水酸碱热力学平衡描述碳酸盐系统的几个参数。因此，溶解无机碳（DIC），氢离子浓度（pH值），总碱度（TA）和二氧化碳分压（pCO2）的单独或更常见的组合测量为我们提供了确定初级生产，呼吸和碳酸钙沉淀和溶解对海洋化学的影响的能力。虽然自从采用技术来测量所有可直接观察到的参数以来，CO2系统的地理和时间数据覆盖面有所扩大，但海洋数据库中仍然存在着巨大的差距。特别的黑点是极地海洋，特别是在海冰覆盖下。这是一个重要的考虑因素，特别是因为极地海洋正在经历海洋酸化造成的环境变化，这种变化在内陆的北冰洋尤为迅速。此外，海冰的存在增加了极地环境的复杂性，因为它是一个由许多相互连接或孤立的微生境组成的动态环境，这些微生境在海冰形成和衰减的季节性周期中扩张和收缩。对复杂的海冰环境的研究很重要，因为它现在被认为是海洋和大气之间相互作用的活跃界面，碳物种通过它转化和迁移。有关极地海洋的生物地球化学信息有限，部分原因是其相对难以获取，特别是当有冰盖、环境复杂以及在恶劣条件下工作困难时，而且还由于缺乏适当的工作方法。在这些温度下以及对用于确定这些条件下二氧化碳系统参数的平衡常数值变化的了解。因此，与温度在零度以上的大洋沃茨相比，我们对极地近零度沃茨和海冰富盐水微生境中的CO2系统的认识是初步的，（TA、DIC、pH、pCO2）在某些极地环境中可以可靠地测量，这意味着必须计算未测量或不可测量参数的值，这一过程需要外推物理化学方程，实际上只应该在零度以上的温度和盐度小于50的情况下使用。这种类型的外推可能会导致在计算的二氧化碳分压和pH值的差异很大。因此，我们的研究的目的是提供必要的分析工具和实验数据，使二氧化碳系统在极地环境中可以进行调查，目前提供的温带和热带的温度和盐度条件相同的复杂程度。为了能够实现这一目标，我们选择了现有的测量海洋沃茨中pH值和pCO2的方法，我们可以可靠地修改这些方法，以在零度以下的温度下测量富含盐水的溶液中的相同参数。使用我们的高质量测量，我们将确定确定CO2系统所必需的系数，并随后通过测量CO2系统的任何2个（4个中的）直接可观察的物理化学参数来预测剩余的两个参数来测试这种方法的有效性。在海洋社区，使用这些常数，工具和分析方法将有助于调查正在进行的和未来的变化，在二氧化碳化学，碳基通量和饱和度方面的碳酸钙矿物在高纬度海洋，设置重要的约束模型预测过去，现在和未来的气候漂移。

Our understanding of the biogeochemical cycling of carbon in the oceans has been revolutionised through our ability to analyse several of the parameters that describe the carbonate system via gas exchange and the aqueous acid-base thermodynamic equilibria. Thus, the individual, or more commonly, combined measurement of dissolved inorganic carbon (DIC), hydrogen ion concentration (pH), total alkalinity (TA) and the partial pressure of carbon dioxide (pCO2) has provided us with the ability to determine the influence that primary production, respiration, and calcium carbonate precipitation and dissolution have on the chemistry of the oceans. Although the geographical and temporal data coverage of the CO2 system has increased since the inception of techniques to measure all its directly observable parameters, large gaps still exist in the oceanic data base. Particular black spots are the polar oceans and especially under sea ice cover. This is an important consideration, especially as the polar oceans are experiencing environmental change as a result of ocean acidification, which is particularly rapid in the land-locked Arctic Ocean. In addition, the presence of sea ice adds complexity to the polar environment as it consists of a dynamic environment of numerous inter-connected or isolated micro-habitats that expand and contract during the seasonal cycle of formation and decay of sea ice. The study of the complex, sea ice environment is important as it in now recognized as an active interface in the interaction between the ocean and the atmosphere, through which carbon species, transform and migrate. The biogeochemical information about the polar oceans is limited in part due to its relative inaccessibility, especially when there is ice cover, the complexity of the environment and the difficulty in working in harsh conditions, but also due to a lack of appropriate methods to work at these temperatures and knowledge of the change in the value of equilibrium constants used in determining parameters of the CO2 system under these conditions. Thus, our knowledge of the CO2 system at near-zero polar waters and the sub-zero temperatures in the brine enriched micro-habitats of sea ice is currently rudimentary compared with that in oceanic waters where the temperature is above-zero.As not all of the parameters that can describe the CO2 system fully (TA, DIC, pH, pCO2) can be reliably measured in some of the polar environments, this has meant that the value of the unmeasured or unmeasurable parameters must be calculated, a process that requires extrapolation of physical-chemical equations that really should only be used with above-zero temperatures and salinity less than 50. This type of extrapolation of can lead to large differences in the calculated pCO2 and pH. Thus, the aim of our research is to provide the necessary analytical tools and experimental data so that the CO2 system in polar environments can be investigated with the same degree of sophistication as that currently afforded in temperate and tropical temperature and salinity conditions. To be able to achieve this, we have chosen existing methods of measuring pH and pCO2 in ocean waters, which we can reliable modify to measure the same parameters in brine enriched solutions at sub-zero temperatures. Using our high quality measurements, we will determine the coefficients that are essential for the determination of CO2 system and subsequently test the validity of this approach by measuring any 2 (out of 4) directly observable physical-chemical parameters of the CO2 system to predict the remaining two. In the marine community, the use of these constants, tools, and analytical methodology will aid investigation of ongoing and future changes in the CO2 chemistry, carbon-based fluxes, and saturation with respect to calcium carbonate minerals in high latitude oceans, setting important constraints on model predictions of past, present, and future climate excursions.