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

碳酸盐体系在零度以下的温度和高离子强度下。

基本信息

批准号：
NE/J007129/1
负责人：
Matt Mowlem
金额：
$ 22.87万
依托单位：
NATIONAL OCEANOGRAPHY CENTRE
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2012
资助国家：
英国
起止时间：
2012 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ007129%2F1
关键词：
carbonate system sub zero temperatures

项目摘要

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.

我们对海洋中碳的生物地球化学循环的理解已经通过我们通过气体交换和水酸碱热力学平衡分析描述碳酸盐系统的几个参数的能力发生了革命性的变化。因此，对溶解无机碳（DIC）、氢离子浓度（pH）、总碱度（TA）和二氧化碳分压（pCO2）的单独或更常见的组合测量使我们能够确定初级生产、呼吸和碳酸钙沉淀和溶解对海洋化学的影响。虽然CO2系统的地理和时间数据覆盖范围自采用测量其所有直接可观测参数的技术以来有所增加，但海洋数据库仍然存在很大的差距。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的环境变化，而海洋酸化在被陆地包围的北冰洋尤其迅速。此外，海冰的存在增加了极地环境的复杂性，因为它是由许多相互联系或孤立的微栖息地组成的动态环境，这些微栖息地在海冰形成和衰减的季节性循环中扩张和收缩。复杂的海冰环境的研究是重要的，因为它现在被认为是海洋和大气相互作用的一个活跃的界面，通过它，碳物种，转化和迁移。关于极地海洋的生物地球化学信息是有限的，部分原因是相对难以获取，特别是当有冰覆盖时，环境的复杂性和在恶劣条件下工作的困难，但也由于缺乏在这些温度下工作的适当方法和在这些条件下用于确定CO2系统参数的平衡常数值变化的知识。因此，与温度在零度以上的海洋水域相比，我们目前对接近零度的极地水域和温度在零度以下的富含盐水的海冰微栖息地的二氧化碳系统的了解还很初级。由于在某些极地环境中，并非所有能够完全描述CO2系统的参数（TA， DIC, pH, pCO2）都可以可靠地测量，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，而这些方程实际上只应用于高于零度的温度和低于50的盐度。这种类型的外推可能导致计算出的二氧化碳分压和ph值的巨大差异。因此，我们研究的目的是提供必要的分析工具和实验数据，以便在极地环境中对二氧化碳系统进行研究，其复杂程度与目前在温带和热带温度和盐度条件下所提供的相同。为了实现这一目标，我们选择了现有的测量海水pH值和二氧化碳分压的方法，我们可以可靠地修改这些方法，以在零度以下的富含盐水的溶液中测量相同的参数。使用我们的高质量测量，我们将确定对确定CO2系统至关重要的系数，并随后通过测量CO2系统直接可观察到的物理化学参数中的任意2个来测试该方法的有效性，以预测剩余的两个。在海洋群落中，这些常数、工具和分析方法的使用将有助于研究高纬度海洋中二氧化碳化学、碳基通量和碳酸钙矿物饱和度的持续和未来变化，为过去、现在和未来气候变化的模式预测设定重要的约束条件。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures.

DOI：
10.1038/s41598-017-02624-0
发表时间：
2017-05-30
期刊：
Scientific reports
影响因子：
4.6
作者：
Loucaides S;Rèrolle VMC;Papadimitriou S;Kennedy H;Mowlem MC;Dickson AG;Gledhill M;Achterberg EP
通讯作者：
Achterberg EP

The measurement of pH in saline and hypersaline media at sub-zero temperatures: Characterization of Tris buffers

在零度以下温度下测量盐水和高盐介质的 pH 值：Tris 缓冲液的表征