SGER: Environmental History of the White Nile Headwaters

该奖项由探索性研究小额赠款（SGER）项目赞助，将使用资金从东非的阿尔伯特湖收集一系列岩心。研究者和一名本科生将前往艾伯特湖，从艾伯特湖最深的水域收集一套Kullenberg活塞岩心，将这些岩心运送到明尼苏达大学的国家湖沼学研究中心，为这些岩心制定年表，对这些岩心中烧焦的草的表面进行完整的同位素和形态学分析，以评估该地区C3和C4草物种的相对贡献。并结合各种气候和环境条件的代理来研究草物种的变化。阿尔伯特湖位于西部裂谷内，在记录大西洋和印度洋的水汽源对非洲季风的相对贡献的变化，以及为尼罗河提供水源的各种赤道非洲湖泊之间的水文输入变化方面处于有利位置。以前的研究表明，东非湖泊对气候和环境条件的十年尺度突变和这种变化的独特记录非常敏感。阿尔伯特湖新的、年代确定的沉积物岩心可以提供这种气候行为的关键但缺失的细节。在之前的一个奖项（即ATM-9912052/0196564）中，Beuning得到了古气候计划的资助，分析东非湖泊的化石草角质层，以更好地了解热带非洲C3和C4草分布的相对范围随时间的变化。该奖项是在减少预算和工作范围的情况下颁发的，以允许Beuning磨练她对角质层同位素分析的分析技术。结果，伯宁把艾伯特湖从研究地点名单上除名了。然而，在这中间的几年里，博宁成功地证明了她的同位素技术。机缘巧合，2003年春天，在阿尔伯特湖进行了一次商业地震考察。贝宁已经获得了在RV Kilindi上停留几天的时间，以便在湖中取样。湖上没有足够的当地船只进行取芯，因此，商业考察是一个机会，可以经济有效地利用私人和公共资金，为国际社会的古气候研究人员带来可观的回报。通过少量的财政投资，更广泛的科学界可以从一个新的、可公开访问的古气候档案中受益。

This award, under the auspices of the Small Grants for Exploratory Research (SGER) program, will use funds to collect a series of cores from Lake Albert in East Africa. The investigator and an undergraduate student will travel to Lake Albert and collect a suite of Kullenberg piston cores from the deepest waters of Lake Albert, ship the cores to the publicly accessible National Limnological Research Center at the University of Minnesota, develop a chronology for the cores, complete isotopic and morphological analyses of charred grass epidermis in these cores to assess the relative contribution of C3 and C4 grass species in the region, and examine shifts in grass species in conjunction with various proxies of climatic and environmental conditions.Lake Albert is located within the western Rift and is well sited to record shifts in the relative contributions of Atlantic and Indian Ocean moisture sources to the African monsoon as well as changes in the hydrologic input among the various equatorial African lakes that feed the Nile River. Previous research has shown East African lakes to be sensitive to abrupt decadal-scale variability in climate and environmental conditions and unique recorders of such change. New and well-dated sediment cores from Lake Albert could provide critical, yet missing, details of this climatic behavior. In a previous award (i.e., ATM-9912052/0196564), Beuning was funded by the Paleoclimate Program to analyze fossil grass cuticles from East African lakes to better understand changes in the relative extent of C3 and C4 grass distribution in tropical Africa over time. The award was made at a reduced budget and scope of work to allow Beuning to hone her analytical techniques for the isotopic analyses of cuticles. As a result, Beuning left Lake Albert off the list of research sites. In the intervening years, however, Beuning has successfully proved her isotopic techniques. As chance would have it, a commercial seismic expedition is being conducted on Lake Albert in the spring of 2003. Beuning has been offered several days of ship time on the RV Kilindi to core the lake. No local vessels on the lake are sufficient for coring so, the commercial expedition is an opportunity to cost-effectively leverage private and public funds to achieve a significant payoff for the international community of paleoclimtic researchers. With a small financial investment, the wider scientific community could benefit from a new and publicly accessible paleoclimatic archive.