Calcification by amorphous pathways: Establishing effects of acidification and interplays with Mg and biomolecule chemistry

拟议的工作将侧重于理解海洋生物的钙化，并将挑战长期以来认为沉淀是通过经典结晶过程发生的观点。过去许多研究的解释都是基于这一概念。现在看来，大多数产生碳酸盐的生物都是通过非经典的生长过程形成骨架的，这一过程包括一个无定形的阶段，随着时间的推移，这个阶段会转变为中晶的复合物。如果这是真的，那么目前通过分析方解石骨架（无论是最近形成的还是保存在海洋沉积物中的）来推断环境影响和解释古记录的方法将需要修改，因为通过非经典过程形成的骨架依赖于一组不同的化学和环境条件。拟议的研究将建立在最近的发现之上，这些发现表明酸化、镁浓度、生物分子化学和其他因素都会影响这条矿化途径。该项目将利用实验室研究和创新的分析方法来研究基于这种新范式的一些假设。动力学和热力学测量和建模将与化学和结构研究相结合，以建立生物矿化途径的完整物理图像。该研究的科学广泛影响超出了化学海洋学领域，如果提出的假设得到证实，将产生重大影响。该项目具有重要的教育意义，包括研究生和本科生参与研究，并通过美国国家科学基金会资助的“从地球到生命”系列项目发展K-12教育。

The proposed work will focus on understanding calcification by marine organisms and will challenge the long-standing view that precipitation occurs via classical crystallization processes. The interpretation of many past studies is based on this notion. It now appears that most carbonate-producing organisms form skeletons by non-classical growth processes which involve an amorphous phase that transforms to a composite of mesocrystals over time. If this is true then the current approaches to inferring environmental effects, and interpreting paleo records, from analysis of calcite skeletons, either recently formed or preserved in marine sediments, will need to be revised as skeleton formation by non-classical processes relies on a different set of chemical and environmental conditions. The proposed research will build on recent findings which suggest that acidification, magnesium concentration, biomolecule chemistry and other factors all influence this pathway to mineralization. The project will investigate a number of hypotheses based on this new paradigm using laboratory studies and innovative analytical approaches. Kinetic and thermodynamic measurements and modeling will be coupled with chemical and structural investigations to establish a complete physical picture of the biomineralization pathway. The scientific broader impacts of the research go beyond the field of Chemical Oceanography and will have substantial impact if the proposed hypotheses are confirmed. The project has significant educational aspects, with the inclusion of both graduates and undergraduates in the research, and K-12 education development through the NSF-funded Earth to Life series.