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: 0551790
• 负责人: Andrew Dickson
• 金额: --
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 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 2010-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0551790&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.

最近的许多工作表明，碳酸钙（CACO3）溶解在水柱中较浅的深度上，而不是通常认为。已经推测，这是由于生物学介导的过程和/或从后期的溶解而发生的。此外，与工业前深度相比，人为二氧化碳的海洋吸收导致了陆和方解石饱和度层的浅滩，这意味着碳酸盐颗粒的溶解会随时间增加。这对我们对非稳态的州海洋碳周期的理解具有重要意义。在这项研究人员的研究人员圣马科斯大学，斯克里普斯海洋学研究所，南佛罗里达大学将衡量直接在模拟的温度和压力的天然海水中，直接在天然海水中衡量新鲜生物碳酸盐的溶解速率。 他们还将研究一些过程 - 两种过程 - 生物学介导的过程以及仅取决于散装二氧化碳浓度的过程 - 可能会影响它们在上水柱中的溶解（1500 m）。该实验将使用由分泌方解石板（Coccoliths）相互锁定在细胞表面和euthecosomatos pteropods和euthecosomatous pteropods（Molluscs）中形成覆盖物的CaCo3（单细胞藻类）产生的，这些CACO3会产生覆盖层。这些有机体几乎解释了我们北太平洋研究区域中CACO3的所有出口通量。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的基础上，并将采用涉及放射性示踪剂的方法/测量的组合，包括放射性示踪剂，CO2化学，包括高压力pH细胞，包括高压力pH细胞，尤其是为该工作构建的，并记录了该工作，并记录了精液和量化和定量的量化和定量。除了进行一系列严格控制的实验室实验外，该团队还将对Clivar重复16N线进行现场研究，并在亚亚贵族太平洋地区的加拿大线P时间序列上进行三年巡航，对新鲜收集的样品进行实验，这些样本与我们的实验室研究相似。在原位饱和条件下的精确度，样本量和观察能力方面，AT-SEA溶解测量系统将具有最先进的能力。使用新鲜的生物碳酸盐，没有事先溶解病史或有机保护涂层的降解均具有高度敏感的方法（测量pH的pH photive to photive to photive to photigotive seplative photive sejeptrictial-photigotive seplative photive to hoseptive 45ca），以实现的45ca进行测量。在上海上发生的近平衡状况下的解散率。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。 这也将为研究生和本科生（RUI）学生提供培训和支持。