Collaborative Research: RUI - Dissolution kinetics of biogenic calcium carbonates in the upper water column of the North Pacific

合作研究：RUI - 北太平洋上部水体中生物碳酸钙的溶解动力学

• 批准号: 0551726
• 负责人: Victoria Fabry
• 金额: $ 44.87万
• 依托单位: California State University San Marcos Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0551726&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Dissolution; kinetics

A variety of recent work suggests that biogenic calcium carbonate (CaCO3) is dissolving at shallower depths in the water column than had been conventionally thought. It has been speculated that this is occurring as a result of biologically mediated processes and/or from the dissolution of aragonite. Moreover, the oceanic uptake of anthropogenic CO2 has resulted in the shoaling of the aragonite and calcite saturation horizons compared to pre-industrial depths, implying that the dissolution of carbonate particles will increase over time. This has significant implications for our understanding of the non-steady state marine carbon cycle.In this study researchers at the California State University at San Marcos, Scripps Institution of Oceanography, and the University of South Florida will measure dissolution rates of fresh biogenic carbonates directly in natural seawater under simulated in situ conditions of temperature and pressure. They will also investigate some of the processes - both biologically-mediated ones and those simply dependent on bulk CO2 concentrations - that may influence their dissolution within the upper water column (1500 m). The experiments will use CaCO3 produced by coccolithophores (single-celled algae) that secrete calcite plates (coccoliths) that interlock to form a covering on the cell surface and by euthecosomatous pteropods (molluscs) that produce protective shells of aragonite. These groups of organisms account for nearly all of the export flux of CaCO3 in our North Pacific study area.The interdisciplinary approach will build on the team members individual knowledge of both carbonate biology and chemistry and will employ a combination of methods/measurements involving radioactive tracers, CO2 chemistry including a high-pressure pH cell constructed especially for this work, and SEM to document and quantify dissolution. In addition to a series of rigorously controlled laboratory experiments, the team will conduct field studies on the CLIVAR repeat line 16N and on three annual cruises on the Canadian Line P time-series in the subarctic Pacific, performing experiments on freshly collected samples that parallel our laboratory studies. The at-sea dissolution measurement system will have state-of-the-art capabilities with respect to precision, sample size, and a capability for observation at in situ saturation conditions.The use of fresh biogenic carbonates with no prior dissolution history or degradation of organic protective coatings coupled with two highly sensitive methods (spectrophotometric pH determinations and radioactive 45Ca) should enable these researchers to make high-quality measurements of dissolution rates at near-equilibrium conditions that occur in the upper ocean.In terms of broader impacts, the project would involve international collaboration with Canadian colleagues. It would also make provision for the training and support of graduate and undergraduate (RUI) students.

最近的各种研究表明，生物碳酸钙（CaCO 3）在水柱中溶解的深度比传统认为的要浅。据推测，这是由于生物介导的过程和/或文石的溶解而发生的。此外，海洋吸收的人为CO2导致的文石和方解石饱和层变浅相比，工业化前的深度，这意味着碳酸盐颗粒的溶解将随着时间的推移而增加。在这项研究中，加州州立大学圣马科斯分校、斯克里普斯海洋研究所和南佛罗里达大学的研究人员将在模拟的原位温度和压力条件下，直接测量新鲜生物碳酸盐在天然海水中的溶解速率。 他们还将研究一些过程-生物介导的过程和那些简单依赖于大量CO2浓度的过程-这可能会影响它们在上层水柱（1500米）内的溶解。这些实验将使用由颗石藻（单细胞藻类）产生的碳酸钙，这些颗石藻分泌方解石板（颗石），这些方解石板互锁在细胞表面上形成覆盖物，并由产生文石保护壳的真囊体翼足类动物（软体动物）产生。这些生物群几乎占了我们北太平洋研究区CaCO 3的所有输出通量。跨学科方法将建立在团队成员对碳酸盐生物学和化学的个人知识基础上，并将采用涉及放射性示踪剂的方法/测量的组合，CO2化学包括特别为此工作建造的高压pH池，以及SEM来记录和量化溶解。除了一系列严格控制的实验室实验外，该小组还将对CLIVAR重复线16 N进行实地研究，并对加拿大P线时间序列在亚北极太平洋的三次年度巡航进行实地研究，对新鲜收集的样品进行实验，与我们的实验室研究平行。海上溶解测量系统将在精度、样本量、使用新鲜的生物碳酸盐，没有先前的溶解历史或有机保护涂层的降解，再加上两种高灵敏度的方法，（分光光度法pH值测定和放射性45 Ca）应使这些研究人员能够在近就更广泛的影响而言，该项目将涉及与加拿大同事的国际合作。 它还将为研究生和本科生的培训和支助作出规定。