Applications of organic geochemistry to paleolimnological reconstructions: a summary of examples from the Laurentian Great Lakes
Applications of organic geochemistry to paleolimnological reconstructions: a summary of examples from the Laurentian Great Lakes
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DOI：
10.1016/s0146-6380(02)00168-7
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发表时间：
2003-01-01
影响因子：
3
通讯作者：
Meyers, PA
中科院分区：
文献类型：
--
作者：
Meyers, PA
湖泊沉积物的有机质含量包含的信息有助于重建过去的环境条件，评估气候变化的历史，并评估人类对当地生态系统的影响。沉积物中埋藏的有机物的元素、同位素和分子组成为湖泊及其集水区的生物群提供了证据，并作为有机物输送和积累的替代物。北美五大湖的沉积记录提供了有机地球化学在古湖泊重建中的应用实例。这些湖泊的记录可以追溯到大约12万年前劳伦泰德冰盖的退缩，包括全新世中期的高温，并显示了最近人类变化的后果。低C-org/N-总的比例表明，大部分的沉积物有机质在五大湖是从藻类生产，但生物标志物分子组成的变化也表明，不同量的陆地植物有机质已交付给湖泊。藻类生产力的提高，伴随着营养丰富的湖泊沃茨被记录为游览较少的负三角洲（13）C值的沉积物中的有机物沉积。在20世纪60年代和70年代。有机碳质量积累率的增加反映了五大湖大部分地区的同位素漂移。石油残留物和热解多环芳烃的积累;在沉积物中，确定有机物质成分向五大湖不同部分的河流和风成输送。新兴的应用程序的多个和新的有机地球化学代理古湖泊重建是有前途的，但一些潜在的重要测量仍然没有得到充分利用。(C)2002爱思唯尔科技有限公司版权所有。
The organic matter content of lake sediments contains information that helps to reconstruct past environmental conditions, evaluate histories of climate change, and assess impacts of humans on local ecosystems. The elemental, isotopic, and molecular compositions of organic matter buried in sediment provide evidence of the biota that have lived in a lake and its catchment area, and they serve as proxies of organic matter delivery and accumulation. Sedimentary records from the North American Great Lakes provide examples of applications of organic geochemistry to paleolimnological reconstructions. The records of these lakes date from retreat of the Laurentide ice sheet around 12 ka, include the mid-Holocene Hypsithermal, and show consequences of recent human changes. Low C-org/N-total ratios indicate that most of the sediment organic matter in the Great Lakes is from algal production, yet changes in biomarker molecule compositions also show that varying amounts of land-plant organic matter have been delivered to the lakes. Elevated algal productivity that accompanies nutrient enrichments of lake waters is recorded as excursions to less negative delta(13)C values in the organic matter of sediments that were deposited. in the 1960s and 1970s. Increased organic carbon mass accumulation rates mirror the isotopic excursions in most parts of the Great Lakes. Accumulations of petroleum residues and pyrogenic polycyclic aromatic hydrocarbons; in sediments identify fluvial and eolian delivery of organic matter components to different parts of the Great Lakes. Emerging applications of multiple and novel organic geochemical proxies to paleolimnological reconstructions are promising, yet some potentially important measurements remain underutilized. (C) 2002 Elsevier Science Ltd. All rights reserved.