Molecular and isotopic composition of novel biomarkers in diatom frustules as indicators of past ocean conditions

这个项目由华盛顿大学的研究人员与多位同事合作进行，将继续研究在硅藻硅藻壳有机基质中发现的有机分子或有机化合物类别是否是生物体在海洋表层生长的海洋学条件的有用生物标志物。这些生物标志物是有用的，因为硅藻负责全球初级生产力的很大一部分，并在全球分布，确保其广泛的适用性。硅藻壳主要由硅质组成，但在生物矿化过程中，硅质基质中捕获了有机化合物。这种有机模板在古海洋学和相关研究中大多未被利用，但最近的工作表明，这些化合物是潜在的有用的生物标志物。此外，有机分子中碳和氮的同位素特征可能会提供额外的信息，并深入了解生长过程中的海洋条件。因此，本项目将调查硅藻细胞壳中有机化合物的组成，并采用分子同位素分析硅藻细胞壳中有机化合物，以充分发挥硅藻细胞壳作为生态系统、地球化学循环和气候变化记录器的潜力。该项目将主要涉及受控的实验室培养研究，但也将检查实地种群和表层沉积物样本，以检查影响硅藻壳有机模板的因素，特别是从这些硅藻壳中提取的类菌孢素氨基酸、长链多胺和几丁质的分子和同位素组成。该项目还将研究物种组成是否影响同位素特征。 这些结果可以提供合适的生物标志物，反映不同的重要海洋条件，如过去的营养盐利用，和环境压力（紫外线和营养盐）。该项目将提供检查海洋气候反馈的新方法，这将有助于澄清海洋对重大制度转变的反应。该项目将支持一名博士后研究员和一名研究生，并将继续与俄罗斯科学家进行国际合作。研究人员还将与华盛顿大学海洋科学教育卓越中心（COSEE）进行互动和参与，并为K-12学生开展外联活动。

This project by investigators from the University of Washington, and in collaboration with various colleagues, will continue to examine whether the organic molecules or classes of organic compounds found in the organic matrix of diatom frustules are useful biomarkers for the oceanographic conditions under which the organisms grew in the surface ocean. These biomarkers are useful as diatoms are responsible for a substantial fraction of global primary productivity and are globally distributed, ensuring their widespread applicability. Frustules are composed primarily of silica, but there are organic compounds entrapped in the siliceous matrix during biomineralization. This organic template is mostly unexploited in paleoceanographic and related studies, but recent work has suggested that these compounds are potential useful biomarkers. Additionally, it is possible that the isotopic signature of carbon and nitrogen in the organic molecules may provide additional information and insight into ocean conditions during growth. Therefore, this project will investigate the organic compound composition and employ molecular isotope analyses of organic compounds in diatom frustules to fully capture the potential of diatom frustules as recorders of the changes in ecosystems, biogeochemical cycles and climate. The project will involve mainly controlled laboratory culture studies, but will also examine field populations and surface sediment samples, to examine the factors that influence the organic template of frustules, and specifically the molecular and isotopic composition of mycosporine-like amino acids, long chain polyamines and chitin extracted from these frustules. The project will also examine whether species composition influences the isotopic signature. The results could provide suitable biomarkers reflective of different important oceanographic conditions, such as past nutrient utilization, and environmental stress (UV and nutrient). The project will provide new methods to examine ocean-climate feedbacks that will help clarify the response of oceans to major regime shifts. The project will support a post-doctoral investigator and a graduate student, and will involve continued international collaboration with Russia scientists. The investigators will also interact and be involved with the University of Washington's Center for Ocean Sciences Education Excellence (COSEE) and work on outreach activities for K-12 students.