Diagenesis of Carotenoid and Chlorophyll Pigments in Lake Sediments

本研究的目的是确定成岩作用在控制湖泊沉积物中类胡萝卜素和叶绿素色素积累中的作用。研究计划包括实地数据收集和实验室实验。实地方法包括测量来自一组对比湖泊的沉积物圈闭和沉积物岩心中母色素及其衍生物的浓度。一组对比湖泊沉积物捕集器材料和表层沉积物岩心的比较。沉积物圈闭物质和地表沉积物的比较将用于评估氧状态、沉积物混合、碎屑活性和有机质含量在控制成岩速率中的重要性。实验室实验包括使用藻类培养物生产14c标记的色素，在好氧和厌氧条件下将标记的色素在沉积物中孵育，以及测量沉积物细菌（好氧和厌氧）和食腐生物（手拟虫）降解色素的速率和途径。方法将包括通过HPLC和质谱分析色素和降解产物，并使用210Pb来确定沉积速率、沉积物混合和沉积物聚焦。湖泊沉积物中色素成岩作用的信息将有助于利用沉积物色素剖面来确定有机质来源、藻类类型和初级生产的变化，并评价有机质循环在控制湖泊化学成分方面的作用。所有这些都对湖泊历史的古环境重建和理解生物分子如何发展成地质分子具有重要意义。

The objective of this investigation is to determine the role of diagenesis in controlling the accumulation of carotenoid and chlorophyll pigments in lake sediments. The research plan includes both field data collection and laboratory experiments. The field approach involves measuring the concentrations of parent pigments and their derivatives in sediment traps and sediment cores from a group of contrasting lakes. Comparisons of sediment trap material and surface sediment cores from a group of contrasting lakes. Comparisons of sediment trap material and surface sediments will be used to evaluate the importance of oxygen status, sediment mixing, detritivore activity, and organic matter content in controlling diagenesis rates. Laboratory experiments involve production of 14C-labelled pigments using algal cultures, incubation of labelled pigments in sediments under aerobic and anaerobic conditions, and measurement of the rates and pathways of pigment degradation by sediment bacteria (aerobic and anaerobic) and a detritivore (chironomids). Methodology will include analysis of pigments and degradation products by HPLC and mass spectrometry and use of 210Pb to determine sedimentation rates, sediment mixing, and sediment focusing. Information on pigment diagenesis in lake sediments will facilitate using sediment pigment profiles to determine organic matter sources, changes in algal types and primary production, and to evaluate the role of organic matter cycling in controlling the chemical composition of lakes, all of primary importance to paleoenvironmental reconstruction of lake history and to understanding of how biomolecules develop into geomolecules.