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和不同的同事合作，将继续研究在硅藻体的有机基质中发现的有机分子或有机化合物类别是否是海洋环境中有用的生物标志物，这些生物是在海洋表面生长的。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，并且分布在全球，确保了它们的广泛适用性。结晶体主要由二氧化硅组成，但在生物矿化过程中，有机化合物被包裹在硅质基质中。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，并深入了解生长期间的海洋条件。因此，本项目将通过对硅藻体有机化合物组成的研究和有机化合物的分子同位素分析，充分挖掘硅藻体作为生态系统、生物地球化学循环和气候变化记录者的潜力。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地表沉积物样本，以检查影响菌落有机模板的因素，特别是从这些菌落中提取的类真菌菌素氨基酸、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会影响同位素特征。该结果可提供反映不同重要海洋条件的生物标志物，如过去的养分利用和环境胁迫（紫外线和养分）。该项目将提供新的方法来检查海洋-气候反馈，这将有助于澄清海洋对主要政权转变的反应。该项目将支持一名博士后研究员和一名研究生，并将涉及与俄罗斯科学家的持续国际合作。调查人员还将与华盛顿大学海洋科学卓越教育中心（COSEE）进行互动和参与，并为K-12学生开展拓展活动。

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.