Controls on Carbon Isotopic Fractionation in Emiliania Huxleyi

艾米利亚赫胥黎碳同位素分馏的控制

• 批准号: 0094637
• 负责人: Brian Popp
• 金额: $ 39.21万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-02-15 至 2006-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0094637&HistoricalAwards=false
• 关键词: Controls; Carbon; Isotopic; Fractionation; Emiliania; Controls; Carbon; Isotopic; Fractionation; Emiliania

Although laboratory and field studies suggest that isotopic analyses of alkenones show great potential as a CO2 proxy because cell geometry may be estimated, the relationship between specific growth rate and carbon isotopic fractionation in natural samples has not been well defined. For this reason, the principal investigators will develop and evaluate a novel method based on combining 13C labeling and isotope-ratio-monitoring gas chromatography-mass spectrometry to determine in situ growth rates of Emiliania huxleyi and Gephyrocapsa oceanica in the ocean. The objectives of this research are to define the range of growth conditions where the 13C-alkenone-labeling technique gives reliable estimates of growth rate and to identify under what conditions bias may be anticipated. In additions, the principal investigators will evaluate the effects of nutrient and light limitation on carbon isotopic fractionation and explore how culture techniques affect 13C labeling and the relationship between carbon isotopic fractionation, growth rate and aqueous CO2 concentrations using dilute batch versus continuous culturing experiments. Lastly, in a select suite of experiments, the rate of incorporation of 13C into alkenones will be compared with other lipids for E. huxleyi and G. oceanica to provide insight into the physiological function(s) and biosynthetic pathway(s) of alkenones. A field component will be carried out to compare directly the fractionation relationship in natural alkenone-producing algae with those developed in laboratory experiments. Results from this study will help calibrate and validate the use of carbon isotopes in alkenones as a CO2 proxy, essential knowledge if the paleoceanographic community is to use this proxy to better understand mechanisms of climate change.

尽管实验室和现场研究表明，由于可以估计细胞几何形状，烯烃的同位素分析表现出很大的潜力，但天然样品中特定的生长速率与碳同位素分馏之间的关系尚未得到很好的定义。 因此，主要研究人员将开发和评估一种基于13C标记和同位素比率监测气相色谱 - 质量质谱法，以确定海洋中艾米尔利亚尼亚Huxleyi和Gephyrocapsa Oceanica的原位增长率。 这项研究的目的是定义13C-烷烃标签技术可靠地估计生长速率的生长条件范围，并在哪些条件下识别可能会偏向偏见。 此外，首席研究人员将评估养分和光限制对碳同位素分馏的影响，并探索培养技术如何影响13C标记以及使用稀释批次与连续培养实验的碳同位素分馏，生长速率和二氧化碳浓度之间的关系。 最后，在一组实验套件中，将13C掺入烯酮的速率将与E. huxleyi和G. oceanica的其他脂质进行比较，以洞悉烯烃的生理功能（S）和生物合成途径。 将进行一个现场成分，以将产生天然烷酮的藻类与实验室实验中开发的藻类直接比较。 这项研究的结果将有助于校准和验证在烯烃中使用碳同位素作为二氧化碳代理，这是基本知识，如果古文学界群落使用该代理来更好地了解气候变化的机制。