Collaborative Research: Investigation of Paleoenvironment, Geomorphic Processes, and Carbon Stocks of Drained Thaw-Lake Basins, Arctic Coastal Plain, Alaska

这是威斯康星大学麦迪逊分校和辛辛那提大学的首席研究人员共同提出的建议。北冰洋沿岸平原约20%被融化的湖泊覆盖，这些湖泊在富含冰的永久冻土上发育，而这一景观的更大比例也被融化的湖盆所留下的伤痕，这些盆地成为有机碳作为泥炭沉积物积累的场所。首席调查员将根据2000-2002年在巴罗半岛所做的工作，研究融化湖盆地的起源和相关的地貌、生物和土壤学过程。高分辨率多光谱卫星数据将量化大小、频率分布，并得出沿海平原上湖泊和排水融化湖盆的形态特征。此外，巴罗和阿特卡苏克之间将选择排水的湖盆进行密集的地面分析。PI将使用植被来选择相同数量的年轻、中等、古老和古老的排水解冻湖盆。将使用探地雷达和广泛的冬季土壤取心来绘制下伏湖泊沉积物和排水后有机沉积物之间的不整合图。结合卫星图像确定面积维度，将估计40个盆地内的有机物体积，以确定有机层和上游湖泊沉积物中储存的土壤碳的数量。这些结果将估计碳在排水盆地中的封存数量。对碎屑湖盆沉积之上的泥炭进行原位放射性测年，将可以估计湖泊排水和盆地形成的日期。有证据表明，这些事件可能与气候变化有关，而其他湖泊则因海岸侵蚀而枯竭。这项研究将使用古生态指标来重建全新世期间沿海平原植被和土壤对气候的时空响应。将使用高频岩心测年来得出碳累积速率和有机土壤化学以及分解状态，以确定碳累积速率是否响应区域气候变化，或者它们是否在更大程度上受当地植物演替速率的影响。对融化湖流域的广泛时空分析将1)增加我们对阿拉斯加北部这些重要景观要素的基本过程的了解，2)提供关于景观尺度对气候变化反应的新信息，3)有助于开发和验证环境变化和碳封存的因果模型。更广泛的影响包括1)获取巴罗当地长老的传统知识，他们拥有关于最近湖泊排水和洪水事件的主要和次要信息；2)通过最近由NASA资助的阿拉斯加土著遥感教育项目，加强巴罗高中学生的教育；3)加强与其他美国机构的联系；以及4)继续通过几个NSF项目为本科生提供科学培训。所有卫星图像、岩心地层学、全球定位系统断面和花粉/微化石数据将通过网站、国家冰雪数据中心档案和北极古环境科学网站公开提供。

This is a collaborative proposal by Principal Investigators at the Universities of Wisconsin-Madison and Cincinnati. About 20% of the Arctic Coastal Plain is covered by thaw lakes developed over ice- rich permafrost and a larger proportion of this landscape is also scarred by drained thaw-lake basins, which become sites for the accumulation of organic carbon as peat deposits. The Principal Investigators will study of the origin of thaw-lake basins and associated geomorphological, biological, and pedological processes, building on work done on the Barrow Peninsula during 2000-2002. High-resolution multispectral satellite data will quantify the size frequency distribution and derive morphometric characteristics for lakes and drained thaw-lake basins across the Coastal Plain. In addition, drained lake basins will be selected for intensive ground-based analysis between Barrow and Atqasuk. The PIs will use the vegetation to select an equal number of young, medium, old and ancient drained thaw-lake basins. Ground-penetrating radar and extensive winter soil coring will be used to map unconformities between underlying lake sediments and the post-drainage organic deposit. Combined with satellite imagery to determine the areal dimensions, the volume of organics within the 40 basins will be estimated to determine the amount of soil carbon stored in the organic layer and upper lacustrine deposits. These results will estimate the amount of carbon sequestered in drained basins. Radiometric dating of the in situ peat above the clastic lake basin sediments will estimate of the date of lake drainage and basin inception. There is evidence to suggest that these events may be related to climatic change, while other lakes have drained in response to coastal erosion. The research will use paleoecological indicators to reconstruct the spatial and temporal response of vegetation and soil to climate on the Coastal Plain during the Holocene. High-frequency core dating will be used to derive carbon accumulation rates and organic soil chemistry and state of decomposition to determine whether carbon accumulation rates respond to regional changes in climate or if they are influenced to a greater degree by local rates of plant succession. Extensive spatial and temporal analysis of thaw-lake basins will 1) add to our understanding of the basic processes responsible for these important elements of the northern Alaskan landscape, 2) provide new information on landscape-scale response to climate change, and 3) help develop and validate causative models of environmental change and carbon sequestering. Broader impacts include 1) accessing traditional knowledge of local elders in Barrow, who have primary and secondary information on recent lake drainage and flooding events; 2) enhancing education of students at the Barrow High School through the recently established NASA-funded Alaskan Native Remote Sensing Education Project; 3) strengthening links with other U.S. agencies; and 4) continuing to provide scientific training to undergraduate students through several NSF programs. All satellite imagery, core stratigraphy, Global Positioning System transects, and pollen/microfossil data will be made publicly available through web sites, archives at the National Snow and Ice Data Center, and the Paleoenvironmental Arctic Sciences web site.