Pure standards of archaeal and bacterial GDGTs for the oceanographic community

各种持续存在于环境中的化合物可以用作海洋系统中各种过程的示踪剂，既包括最近发生的那些过程，也可以用于追踪古时间尺度的变化。近年来，古生物和细菌甘油-二烷基-甘油四醚(GDGT)脂类作为古海洋学和生物地球化学的替代物引起了人们的兴趣，这类研究也是最近的一个研究领域。然而，为了验证不同研究小组正在进行的生物地球化学解释，有必要限制测量并使其属实。准确的纯化学标准对于此类验证至关重要。目前的方法包括对照已知数量的纯品、正品GDGT定期校准合成标准品。然而，由于很少有实验室能够获得真正的GDGT，在古代物研究中缺乏严格的校准。因此，哈佛大学的研究人员提议生产纯GDGT来满足这一需求。这项研究的目标是从沉积物中提取这些脂类，提纯单个化合物，并创建可用于定量和放射性碳工作的参考标准。由于GDGT作为示踪剂在科学上很受欢迎，研究人员的目标是使整个项目向社区开放访问。一旦生成，实验室可以潜在地使用这些标准来检查其制备方法和/或通过仪器校准的分析方法。此外，这些材料可以作为同位素参考材料，类似于从其他机构获得的材料。这项研究的更广泛影响涉及拟议标准将为研究界提供的服务。此外，本科生、研究生和高中生将从项目期间的培训机会中受益。

A variety of chemical compounds that persist in the environment can be used as tracers of a variety of processes in ocean systems, both those occurring in the recent past, as well as being used to trace changes over paleo timescales. There has been recent interest in using archaeal and bacterial glycerol-dialkyl-glycerol tetraether (GDGT) lipids as proxies in paleoceanography and biogeochemistry, and such studies have been an area of recent research. However, there is a need to constrain and ground-truth the measurements in order to validate the biogeochemical interpretations being made by the various research groups. Accurate pure chemical standards are critical for such validation. Current methods involve calibrating a synthetic standard regularly against a known quantity of a pure, authentic GDGT. However, as very few labs have access to the authentic GDGT's, there is a lack of strict calibration in paleoproxy studies. Therefore, researchers from Harvard University have proposed to generate pure GDGT's to meet this need. The goal of this research is to extract these lipids from sediments, purify the individual compounds, and create reference standards that can be used in quantitative and radiocarbon work. Due to the scientific popularity of GDGT's as tracers, it is the researchers' goal to make the entire project "open access" to the community. When generated, laboratories can potentially use these standards to check their preparation methods and/or analytical methods through instrument calibration. Additionally, these materials can serve as isotope reference materials, similar to those available from other institutions. The broader impacts of this research relate to the service that the proposed standards will provide to the research community. In addition, undergraduate, graduate, and high school students will benefit from training opportunities during the project.