The origin of maleimides in recent sediments - Sources, formation processes and palaeoenvironmental implications

近期沉积物中马来酰亚胺的起源 - 来源、形成过程和古环境影响

• 批准号: 253132634
• 负责人: Dr. Sebastian Näher, Ph.D.
• 金额: --
• 依托单位: Centre for Applied Organic Geochemistry
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/253132634?language=en
• 关键词: origin; maleimides; recent; sediments; Sources

Chlorophylls and bacteriochlorophylls are the most abundant and most important pigments on Earth. These compounds and their transformation products (chlorins, porphyrins, metalloporphyrins and maleimides) can be preserved in recent limnic and marine sediments, sedimentary rocks and crude oils and serve as valuable palaeoenvironmental proxies. Among these, maleimides (1H-pyrrole-2,5-diones), the assumed oxidation products of tetrapyrroles (i.e. chlorophylls, bacteriochlorophylls, related derivatives, hemes, phycobilins) have so far hardly been studied in recent sediments, most studies being focused on ancient deposits. Their formation processes are still incompletely understood and precursors of many maleimides are not known. In this project, the characterisation of maleimides in aquatic systems with different biogeochemical history will expand the very limited knowledge of maleimide sources and formation pathways in recent aquatic environments, which represents an important step to accurately apply them as biomarkers. These markers might be used for instance to describe changes in productivity and carbon cycling, microbial community structure, water column properties (e.g. photic zone anoxia/euxinia (persistent versus periodic), chemocline depth) and depositional conditions during sedimentation and diagenesis. This project aims at identifying maleimide sources by analysis of their distributions and comparing these with tetrapyrroles obtained in the same samples. Existing analytical procedures to determine maleimides with apolar functional groups will be modified to include polar maleimides. It is, hence, the first attempt to analyse polar maleimides in recent sediments. Furthermore, stable carbon and nitrogen isotope signatures of maleimides will be measured in environmental samples. This approach will enhance the understanding of the metabolism and cycling of organic carbon and nitrogen and to reconstruct changes in productivity, nutrient cycling and food web relationships.

叶绿素和细菌叶绿素是地球上最丰富和最重要的色素。这些化合物及其转化产物（氯、卟啉、金属卟啉和马来酰亚胺）可保存在最近的湖泊和海洋沉积物、沉积岩和原油中，并可作为有价值的古环境指标。其中，马酰亚胺（h -吡咯-2,5-二酮），四吡咯（即叶绿素、细菌叶绿素、相关衍生物、血红素、藻胆素）的假设氧化产物，迄今为止在近代沉积物中几乎没有研究，大多数研究集中在古代沉积物中。它们的形成过程仍不完全清楚，许多马来酰亚胺的前体尚不清楚。在本项目中，具有不同生物地球化学历史的水生系统中马来酰亚胺的特征将扩展对现代水生环境中马来酰亚胺来源和形成途径的非常有限的认识，这是将其准确应用于生物标志物的重要一步。这些标记物可用于描述沉积和成岩过程中生产力和碳循环、微生物群落结构、水柱性质（如光带缺氧/缺氧（持续与周期性）、趋化斜深度）和沉积条件的变化。该项目旨在通过分析马来酰亚胺的分布，并将其与同一样品中获得的四吡啶进行比较，从而确定马来酰亚胺的来源。现有的测定具有极性官能团的马来酰亚胺的分析方法将被修改为包括极性马来酰亚胺。因此，这是首次尝试分析近期沉积物中的极性马来酰亚胺。此外，将在环境样品中测量马来酰亚胺的稳定碳和氮同位素特征。这种方法将增强对有机碳和氮的代谢和循环的理解，并重建生产力、营养循环和食物网关系的变化。