Linking Archaeal Membrane Lipids and Ecology in Great Lakes: Understanding the TEX86 Paleotemperature Proxy

将古细菌膜脂质与五大湖生态联系起来：了解 TEX86 古温度代理

• 批准号: 0452927
• 负责人: Josef Werne
• 金额: --
• 依托单位: University of Minnesota Duluth
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0452927&HistoricalAwards=false
• 关键词: Linking; Archaeal; Membrane; Lipids; Ecology

ABSTRACTOCE-0452927Paleotemperature is difficult to measure in great lakes systems. The recent establishment of the relationship between crenarchaeotal membrane lipids (GDGTs) and mean annual lake surface temperature provides a powerful and much needed lake temperature reconstruction tool. Unfortunately, very little is known about the ecology of the Crenarchaeota from which these GDGT compounds are derived. Many questions remain before we can understand why the membrane lipids derived from the Crenarchaeota seem to reflect sea or lake surface temperatures. Presently, the potential for the membrane lipids from these archaea to be used for paleotemperature reconstruction is based solely on core-top calibrations from a diverse suite of marine and large lake environments.In this project, researchers at the University of Minnesota at Duluth will attempt to link the production of GDGTs in the water column of Lake Superior with specific aspects of the ecology of the Crenarchaeota in order to improve our understanding of the Crenarchaeota themselves as well as to determine whether the GDGT distribution identified in sediments reflects lake surface temperature and whether other factors are influencing the apparent temperature signal preserved by these crenarchaeotal membrane lipids.The research team will study the GDGT membrane lipids and nucleic acids of Crenarchaeota in the water columns and sediments of Lake Superior (North America) and Lake Malawi (East Africa). In Lake Superior, they will identify the time of the year when these compounds are most abundance in settling particulate organic matter and their fluxes to the sediment using sediment traps. They will also intend to identify specific depths where these crenarchaeotal compounds are dominant by analyzing them in suspended particulate matter (SPM) at various depths in the water column. Finally, the diversity of GDGT membrane lipids will be compared with the diversity of archaeal communities in both SPM and sediments from Lakes Superior and Malawi to examine whether variations in archaeal diversity are reflected in GDGT distributions. The project outlined in this proposal is expected to lay the groundwork for understanding the mechanistic link between the TEX86 paleotemperature index and water temperature in great lakes. Ultimately, results from this study should lead to the confident application of the TEX86 index by other scientists to address continental paleoclimate questions in lake systems worldwide.Broader Impacts: The broader impacts of this project include training of graduate and undergraduate students, both in field methods as well as state-of-the-art analytical methods and enhancement of national and international scientific collaborations. This study will also greatly increase our understanding of the mechanistic links between the TEX86 paleotemperature proxy and archaeal communities in great lakes, giving us a useful tool to help understand past, present, and future global climate and environmental change.

摘要大湖区的古地温是难以测量的。新建立的膜脂（GDGTs）与年平均湖表面温度之间的关系为湖泊温度重建提供了一个强有力的工具。不幸的是，我们对产生这些GDGT化合物的绿原藻的生态学知之甚少。在我们能够理解为什么从绿藻中提取的膜脂似乎反映了海洋或湖泊表面温度之前，还有许多问题有待解决。目前，这些古细菌的膜脂用于古温度重建的潜力仅基于来自不同海洋和大型湖泊环境的岩心顶部校准。在这个项目中，明尼苏达大学德卢斯分校的研究人员将尝试将苏伯利尔湖水柱中GDGT的产生与绿原藻生态的特定方面联系起来，以提高我们对绿原藻本身的了解，并确定沉积物中发现的GDGT分布是否反映了湖表面温度，以及是否有其他因素影响这些绿原藻膜脂保存的表观温度信号。研究小组将对北美苏必利尔湖和东非马拉维湖水柱和沉积物中绿古藻的GDGT膜脂和核酸进行研究。在苏必利尔湖，他们将利用沉积物捕集器确定一年中这些化合物沉降颗粒有机物质最丰富的时间，以及它们向沉积物的通量。他们还打算通过分析水柱中不同深度的悬浮颗粒物（SPM）来确定这些crenarchaeotal化合物占主导地位的特定深度。最后，将GDGT膜脂的多样性与SPM和苏必利尔湖和马拉维湖沉积物中古菌群落的多样性进行比较，以检验古菌多样性的变化是否反映在GDGT分布中。本项目将为了解TEX86古温度指数与五大湖水温之间的机制联系奠定基础。最终，这项研究的结果将导致其他科学家对TEX86指数的自信应用，以解决全球湖泊系统的大陆古气候问题。更广泛的影响：该项目的更广泛的影响包括培训研究生和本科生，在实地方法和最先进的分析方法方面，以及加强国家和国际科学合作。该研究还将大大增加我们对TEX86古温标与五大湖古细菌群落之间的机制联系的认识，为我们了解过去、现在和未来的全球气候和环境变化提供有用的工具。