Collaborative Research: Biomineralization Processes and their Environmental Modulation in Marine Bivalves

合作研究：海洋双壳类生物矿化过程及其环境调节

• 批准号: 1557870
• 负责人: Adam Reitzel
• 金额: $ 38.3万
• 依托单位: University of North Carolina at Charlotte
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1557870&HistoricalAwards=false
• 关键词: Collaborative; Research; Biomineralization; Processes; their

Bivalve mollusks such as oysters and clams are ecosystem engineers and important economic resources in estuaries. Bivalves build shells from calcium carbonate (CaCO3), which protect them from predators and environmental stressors and are essential for survival. Mollusks' shells, produced from precursors abundant in the seawater, have unique mechanical properties that make them superior to geological CaCO3. However, they are energetically costly to deposit and can be eroded under corrosive conditions of low salinity, high concentrations of carbon dioxide (CO2) and low pH, characteristic of estuarine waters. Recent studies show that biomineralization of marine bivalves is impaired by prolonged exposure to the moderately elevated CO2 levels (800-2000 ppm), which appears paradoxical since thriving bivalve populations are found in estuaries with a broad range of CO2 levels (400-10,000 ppm). Another recently discovered conundrum is that some mollusks with shells made of the more soluble aragonite are less affected by elevated CO2 levels than those with the shells made of less soluble calcite. These findings challenge the current paradigm in biomineralization and indicate that interactions between the environment and biological controls of biomineralization are more complex than currently recognized. To close this gap in knowledge, the investigators will determine the molecular and cellular mechanisms of biomineralization in mollusks with shells made of different types of CaCO3, assess how these mechanisms are affected by seawater chemistry and identify physiological and energetic constraints on biomineralization in potentially corrosive estuarine waters. The project involves development of an interdisciplinary BioCADRE program for training of undergraduate students, training and mentorship of post-doctoral researchers, and fostering of interdisciplinary collaborations between the University of Pittsburgh and University of North Carolina at Charlotte.This study focuses on the biological mechanisms of mineralization in two keystone bivalve species, Crassostrea gigas and Mercenaria mercenaria with calcitic and aragonitic shells, respectively. The PIs will test the hypotheses that hemocytes and mantle cells utilize different molecular mechanisms of mineral sequestration and transport and that species-specific differences in biomineralization mechanisms contribute to different abilities of these bivalves to build shells at low CaCO3 saturation levels. The PIs will assess how salinity and CO2 levels affect sequestration, transport and deposition of the mineral as well as expression and activity of the proteins involved in matrix formation and acid-base balance. The PIs will determine whether successful biomineralization at low CaCO3 saturation levels leads to elevated costs of basal maintenance and trade-offs between biomineralization and other energy-dependent functions. These studies will elucidate how cellular, molecular and whole-organism processes are orchestrated to support active mineral deposition in a wide range of CaCO3 saturation levels, determine what mechanisms compensate for higher mineral solubility during exposure to hypercapnia and low salinity and assess whether these mechanisms are more effective in aragonite-depositing than calcite-depositing mollusks. This project builds on previous successful collaborations between a biomineralization expert and a mollusk physiologist and has the material and intellectual resources required for its success.

牡蛎和蛤lam之类的双壳类软体动物是河口中的生态系统工程师和重要的经济资源。双壳类动物从碳酸钙（CACO3）中产生壳，该壳保护它们免受捕食者和环境压力的侵害，对于生存至关重要。软体动物的贝壳是由海水丰富的前体产生的，具有独特的机械性能，使其优于地质CACO3。但是，它们的沉积在能量上是昂贵的，可以在低盐度，高浓度二氧化碳（CO2）和低pH值（河口水的特征）的腐蚀性条件下侵蚀。最近的研究表明，海洋双壳类的生物矿化会因长期暴露于中等升高的二氧化碳水平（800-2000 ppm）而受到损害，这似乎是悖论性的，因为在繁荣的双壳类人群中发现了二氧化碳水平广泛（400-10,000 ppm）。最近发现的另一个难题是，一些由壳较溶解的小软体动物比较低的可溶性方解石制成的壳的壳壳的影响较小。这些发现挑战了当前的生物矿化范式，并表明生物矿化的环境与生物控制之间的相互作用比当前认识的要复杂。为了缩小知识的差距，研究人员将确定用不同类型的CACO3制成的壳体中的软体动物中生物矿化的分子和细胞机制，评估这些机制如何受到海水化学的影响，并识别海水和能量约束对潜在腐蚀性腐蚀性雌激素水域生物内化的约束。该项目涉及开发跨学科的生物阿卡德计划，以培训本科生的培训，博士后研究人员的培训和指导，以及培育匹兹堡大学和北卡罗来纳大学在Charlotte大学的跨学科合作。分别是钙质和后壳壳。 PIS将检验血细胞和地幔细胞利用矿物隔离和转运的不同分子机制的假设，生物矿化机制中物种特异性的差异有助于这些双壳类的不同能力来在低CACO3饱和水平下建立壳。 PI将评估盐度和二氧化碳水平如何影响矿物质的隔离，运输和沉积，以及与基质形成和酸碱平衡有关的蛋白质的表达和活性。 PI将确定在低CACO3饱和水平下的成功生物矿化是否导致生物矿化和其他能源依赖性功能之间基础维护和权衡的成本升高。这些研究将阐明如何精心策划细胞，分子和全体生物过程，以支持广泛的CACO3饱和水平的主动矿物质沉积，确定哪些机制补偿了在暴露于高碳酸盐和低盐度期间较高的矿物质溶解度，并评估这些机制是否更有效地在aragonite-aragonite-depopossposspossposscess-colcosists-colcoSsss中更有效。该项目建立在生物矿化专家与软体动物生理学家之间的先前成功合作的基础上，并拥有成功所需的物质和智力资源。