Lipid Biomarker Isotopic Composition Changes during Early Diagenesis in Variable Biogeochemical Sediment Regimes - Implications for Carbon Cycling and Paleoceanography

可变生物地球化学沉积体系中早期成岩作用期间脂质生物标志物同位素组成的变化 - 对碳循环和古海洋学的影响

• 批准号: 0116786
• 负责人: Ming-Yi Sun
• 金额: $ 33.7万
• 依托单位: University of Georgia Research Foundation Inc
• 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: 2001-10-01 至 2005-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0116786&HistoricalAwards=false
• 关键词: Lipid; Biomarker; Isotopic; Composition; Changes

ABSTRACTOCE-0116786Detailed chemical composition studies of the distribution of preserved lipid molecular markers (also termed molecular 'fossils' or 'fingerprints') in the sinking particulate matter of water columns and especially subsequently in sediments provides insight to our understanding of the inputs and processing of organic matter carbon in the ocean. Interpretation of the stable carbon isotopic composition (d 13C) of specific lipid molecular markers in aged sedimentary deposits has increasingly been suggested as a means of constraining past ocean and climate conditions and even reconstructing paleo atmospheric carbon dioxide mixing ratios (pCO2). The PI will measure isotopic d 13C fractionation effects on selected lipids using controlled laboratory experiments to simulate processes reflecting those undergone during natural diagenesis. This investigation will address the otherwise default assumption that diagenetic effects are negligible. Incubation experiments using target lipid biomarkers obtained from enriched 13C labeled algal cultures will be conducted in different biogeochemical regimes including: natural oxic and anoxic seawaters; simulated oxic vs. anoxic and cycled oxic/anoxic sediment-water interfaces; and in homogenized sediment cores with and without macrofauna. Compound specific isotopic analysis of biomarker 'molecular fossils' in sediments enhances understanding of the past conditions experienced by the marine organisms producing such molecules. Use of lipid biomarker information contained in natural archives such as deep sea sediments is key in reconstructing past climate change and helps answer fundamental questions such as how fast and how much can the planet's climate change.

摘要0116786保存的脂质分子标记物（也称为分子“化石”或“指纹”）在水柱中的沉降颗粒物质，特别是随后在沉积物中的分布的详细化学成分研究，为我们了解海洋中有机物碳的输入和处理提供了见解。在古老的沉积物中的特定脂质分子标记物的稳定碳同位素组成（d 13 C）的解释越来越多地被建议作为一种手段，约束过去的海洋和气候条件，甚至重建古大气二氧化碳混合比（pCO 2）。PI将使用受控实验室实验来模拟反映天然成岩作用过程中所经历的过程，从而测量同位素d 13 C分馏对选定脂质的影响。这项研究将解决成岩作用可以忽略不计的假设。将在不同的海洋地球化学体系中进行培养实验，使用从富集13 C标记的藻类培养物中获得的目标脂质生物标志物，包括：天然好氧和缺氧海水;模拟好氧与缺氧和循环好氧/缺氧沉积物-水界面;以及在有和没有大型底栖动物的均质沉积物岩心中。沉积物中生物标志物“分子化石”的化合物特异性同位素分析增强了对产生此类分子的海洋生物所经历的过去条件的理解。使用深海沉积物等自然档案中包含的脂质生物标志物信息是重建过去气候变化的关键，并有助于回答地球气候变化的速度和程度等基本问题。