Doctoral Dissertation Research: Temporal and Spatial Patterns of Holocene Peatland Carbon Dynamics, West Siberian Lowland, Russia

泥炭地生态系统是全球碳循环的重要组成部分，因为在全新世（过去11 000年），泥炭地作为有机土壤从大气中吸收了最大的单一陆地碳储存。 泥炭地生态系统也是当代大气甲烷最重要的来源之一。 使用各种方法对一系列高纬度地区进行的研究表明，北方泥炭地对气候变化高度敏感，以至于它们可以每年从净大气碳汇转换为净碳源。 然而，这些巨大的碳储存在受人为温室气体影响越来越大的气候中将发挥的未来作用仍然不确定。 这些系统的长期碳交换行为需要多年的观察，泥炭地碳循环对气候的响应在十年或更长的时间内仍然缺乏基本的了解。 本博士论文研究项目将应用古生态学工具来研究西伯利亚泥炭地生态系统对过去气候变化的响应。 西西伯利亚低地含有世界上最高密度的泥炭碳，但相对于芬诺斯堪的纳维亚、欧洲和北美的泥炭沉积物，研究得很少。 本研究将使用可识别的植物遗骸，土壤碳特征，和14-C AMS年龄测定的泥炭从广泛收集的核心，调查在西西伯利亚泥炭地的碳动态的时空格局的信息。 具体而言，该项目将（1）确定泥炭地历史上对全新世泥炭地-大气甲烷交换重要的主要生态变化的时空性质，（2）确定全新世泥炭积累率如何受到这些变化的影响，以及（3）评估最近WSL中C积累的模式，以增加对其对现代变暖敏感性的理解。陆地北方生态系统已被然而，这一重要汇的年与年之间的强度是可变的。 陆地上最大的固存碳集中在北美和欧亚大陆内部的泥炭中。 对西西伯利亚低地的研究对于评估北方高纬度环境在全球碳循环中的作用至关重要，因为该地区历史上的碳积累研究相对较少，这里存在大量的碳储存，而且它位于最近北极每十年升温1摄氏度至2摄氏度的焦点。 之前由NSF资助的俄美合作研究已经产生了迄今为止最高质量的泥炭碳清单，以及前所未有的从偏远的西西伯利亚低地难以获得的泥炭记录。 这些初步研究发现，记录覆盖面存在很大的空间缺口，这与该区域南部泥炭碳的最大纬度储存量相吻合。 这个博士论文研究改进奖将允许西伯利亚的最后一场战役，并完成实验室分析。 只有当这一空白被填补时，西西伯利亚低地碳积累历史的全貌才能得到最终的发展。 该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

Peatland ecosystems are significant components in the global carbon cycle, as they have sequestered from the atmosphere the largest single terrestrial carbon stock as organic soils over the course of the Holocene (the last 11,000 years). Peatland ecosystems also are one of the most important contemporary sources of atmospheric methane. Research from a range of high-latitude locations using a variety of methods has revealed that northern peatlands are highly sensitive to climatic variation, to the extent that they can switch interannually from net atmospheric carbon sinks to net carbon sources. The future role that these massive carbon stocks will play in a climate increasingly perturbed by anthropogenic greenhouse gases remains uncertain, however. Long-term carbon exchange behavior of these systems requires many years of observation, and basic understanding of peatland carbon cycling response to climate over decadal or longer periods remains poor. This doctoral dissertation research project will apply paleoecological tools to investigate Siberian peatland ecosystem response to past climatic changes. The West Siberian Lowland contains the world's highest density of peat carbon, yet is poorly studied relative to Fennoscandian, European, and North American peat deposits. This research will use information in identifiable plant remains, soil carbon characteristics, and 14-C AMS age determinations of peat from a wide collection of cores to investigate spatiotemporal patterns of carbon dynamics in West Siberian peatlands. Specifically, the project will (1) determine the spatiotemporal nature of major ecological changes in peatland history important to Holocene peatland-atmosphere methane exchange, (2) determine how Holocene peat accumulation rates have been affected by these changes, and (3) assess recent patterns of C accumulation in the WSL towards increased understanding of their sensitivity to modern warming.Terrestrial Northern Hemisphere ecosystems have been identified as globally critical carbon sinks for excess anthropogenic carbon dioxide, however, the year-to-year strength of this important sink is variable. The greatest terrestrial concentration of sequestered carbon is stored in peats within the continental interiors of North America and Eurasia. Study of the West Siberian Lowland is crucial to the assessment of the role of northern high-latitude environments in the global carbon cycle owing to the relative paucity of historical carbon accumulation studies in the region, the massive carbon stocks present here, and its location at the focus of recent 1-degree Celsius to 2-degrees Celsius per decade Arctic warming. Previous NSF-funded Russian-American collaborative research has resulted in the highest quality peat carbon inventory to date as well as an unprecedented collection of hard-to-get peat records from the remote West Siberian Lowland. These initial studies have identified a large spatial gap in record coverage that is coincident with the maximum latitudinal storage of peat carbon in the south of the region. This Doctoral Dissertation Research Improvement award will allow a final field campaign to Siberia, and completion of laboratory analyses. A complete picture of West Siberian Lowland carbon accumulation history can only be conclusively developed when this gap is filled. This award also will provide support to enable a promising student to establish a strong independent research career.