Isotopic Records in Post-Glacial Lake Sediments: Implications for Biota and Landscape Evolution

冰河后湖泊沉积物中的同位素记录：对生物群和景观演化的影响

• 批准号: 0087364
• 负责人: Andrea Lini
• 金额: $ 8.82万
• 依托单位: University of Vermont & State Agricultural College
• 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: 2001-02-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0087364&HistoricalAwards=false
• 关键词: Isotopic; Records; Post; Glacial; Lake

Lake sediments provide a temporal record of surface and lacustrine processes influenced by environmental and climatic changes. Since environmental changes affect the biological communities in and around lakes, evidence of local and regional environmental histories can be found in the chemical composition of organic material preserved in their sediments. The extreme climatic changes associated with glacial-interglacial transitions had profound ecological impacts, which are recorded in lake sediments. The objectives of this project are to understand how and at what rates lacustrine ecosystems were established in newly created post-glacial lakes, and to investigate the relationship between lake ecosystem and watershed evolution. In order to meet these objectives, sediment cores spanning the whole late Pleistocene-Holocene time interval will be collected from post-glacial lakes in New England. Analyses that will be performed to characterize the sedimentary organic matter include: carbon and nitrogen stable isotopes, organic carbon and nitrogen content, C/N ratios, and hydrogen and oxygen indices. Samples of present-day watershed and lake plants will also be collected for each of the cored lakes. This modern dataset will provide a base for the interpretation of the sedimentary records. The proposed study has significant potential impacts. If, as hypothesized, geochemical records such as those provided by carbon isotopes reflect the individualistic response of the developing lake systems to the local geology, hydrology, and biota, these factors must be considered before attempting correlation of environmental climate proxies on a local, regional, and global scale. Results will also provide constraints on how much time is needed for lake ecosystems to recover from extreme natural or anthropogenic disturbances.

湖泊沉积物提供了受环境和气候变化影响的表面和湖泊过程的时间记录。由于环境变化会影响湖泊和周围周围的生物群落，因此可以在保存在沉积物中的有机材料的化学成分中找到局部和区域环境历史的证据。与冰川间 - 冰川过渡相关的极端气候变化具有深远的生态影响，这些影响记录在湖泊沉积物中。该项目的目的是了解在新创建的冰川后湖泊中建立了湖泊生态系统的方式，以及研究湖泊生态系统与流域演化之间的关系。为了实现这些目标，将从新英格兰的冰川后湖中收集跨越整个更新世的半新世时间间隔的沉积物核心。将进行表征沉积有机物的分析包括：碳和氮稳定的同位素，有机碳和氮含量，C/N比以及氢和氧指数。当今的分水岭和湖泊植物的样品还将为每个核心湖泊收集。该现代数据集将为沉积记录的解释提供基础。拟议的研究具有重大的潜在影响。如果据称，诸如碳同位素提供的地球化学记录反映了发展中的湖泊系统对当地地质，水文学和生物群的个人主义反应，则必须在尝试将环境气候代理在当地，区域和全球规模上进行环境气候代理之前进行考虑。结果还将为湖泊生态系统从极端自然或人为的干扰中恢复需要多少时间提供限制。