Collaborative Research: Long-term carbon storage shifts in high-latitude peatlands with paleoclimate change: Linking peatland modeling with paleoecology and paleohydrology

这是从阿拉斯加北极泥炭地档案中对古气候和长期碳积累之间关系的迭代数据模型研究。假设是气候通过与生产和分解相关的温度和湿度的变化来控制泥炭地的碳储存。利用从冰川晚期到全新世的两个北极地区现有的一套泥炭地岩心，提供了各种气候情景来研究碳封存。例如，该研究小组假设，温暖、干燥的间歇期会导致泥炭地碳储量下降，而凉爽、潮湿的气候会导致碳固存增加。使用新的工具，包括化合物特定的同位素和生物标记物分析，以及现有的传统古气候指标，如花粉、大型化石和苔藓植物，研究人员将产生详细的气候和水文重建，高分辨率的AMS-14C测年、碳和体积密度测量将提供从晚冰川到现在的碳积累速率，并使研究小组能够使用新开发的机械泥炭地积累模型来测试他们的碳固存-气候假说。由于高纬度温暖的北极和亚北极泥炭地为气候系统提供了正向和负向碳反馈，重要的是增加古视角来理解大小和时间和空间尺度。这项研究将结合对高纬度泥炭地上一次冰期-间冰期周期中古生态/古气候变化的详细分析(通过苔藓、化合物特定同位素分析、花粉和大型化石分析)，并对不同环境(即潮湿与干燥的麝香)下的碳固存进行量化。这些古泥炭地历史将提供长期的碳封存记录，可用于与从相同沉积物中重建的古气候以及冰芯、海洋记录和湖泊地层学进行比较。新的全新世泥炭地模型将利用独立的古气候数据来模拟北部泥炭地在几十年到几千年的年度时间步长上的碳和水耦合动力学。然后，可以将模型模拟的碳积累记录与泥炭地的历史进行比较，并从植物组成、生产力和分解的角度评估差异。这种迭代的模型数据研究将提供必要的长期经验信息，以评估未来湿地碳循环中水文循环的作用，以及过去气候和植被在数千年来固碳中的重要性。新采样的选择地点包括阿拉斯加的泥炭地？S北坡图利克湖，那里有广泛的生态数据库，以及台地西部的北极丘陵。AMS 14C年龄以及铅-210和铯-137将与碳和容重结合使用，以确定每个地点的碳积累。苔藓植物和同位素/生物标志物的分析将提供明确的水分状况，以及这些地点火山灰沉积可能造成的水化学变化。特别令人感兴趣的是气候间隔，如博林-阿勒罗德/年轻仙女木期、全新世早期、前北冰纪和8200年事件、全新世中期、新冰期、小冰期和最近50年。该项目将包括至少4篇本科生论文和1篇博士后论文。PI在指导本科生和为基于现场和实验室的项目的研究生提供建议方面有着良好的记录，她以前的许多顾问在同行评议的期刊上发表了他们的结果。学生将有机会展示地方、州和国家层面的成果。该组织将继续其在科学项目中的长期领导地位，培训高中生和教师，美国国家航空航天局/地理信息系统少数民族暑期项目和哥伦比亚大学S地球与环境科学系研究生和本科生，以及当地博物馆和公共项目的外展。他们打算聘请一名K-12教师在拉蒙特·多尔蒂地球观测站(北极/亚北极夏季客座教师)项目中进行实地和实验室研究，以产生深远的影响。此外，他们的分析还可用于国际和平协会教授的哥伦比亚大学关于湿地和气候变化、陆地古气候的课程，以及植物生态学和古生态学的研讨会，以及北卡罗来纳大学国际和平组织教授的课程(生物地球化学和环境建模)。这项工作的结果和结论将对北极气候政策、生态系统管理和教育产生影响。

This is an iterative data-model investigation of the relationship between paleoclimate and long-term carbon accumulation from Alaskan arctic peatland archives. The hypothesis is that climate controls carbon storage in peatlands through shifts in temperature and moisture related processes of production and decomposition. Use of an existing set of peatland cores from two arctic regions from the late-glacial to the Holocene offers a variety of climate scenarios to examine carbon sequestration. For example, the group hypothesizes that warm, dry intervals result in peatland carbon storage decline, while cool, wet climates result in increased carbon sequestration. Using new tools, including compound-specific isotope and biomarker analysis, and existing traditional paleoclimate proxies such as pollen, macrofossils, and bryophytes, the researchers will produce detailed climate and hydrological reconstructions, and high resolution AMS-14C dating, C and bulk density measurements will provide carbon accumulation rates from the late-glacial to the present and enable the team to test their carbon sequestration-climate hypotheses using a newly-developed mechanistic peatland accumulation model. As high latitudes warm and arctic and subarctic peatlands provide positive and negative carbon feedbacks to the climate system, it is important to add the paleo-perspective to our understanding of magnitude and temporal and spatial scales. This research will couple detailed analysis of changes in paleoecology/paleoclimate (through bryophyte, compound-specific isotope analysis, pollen, and macrofossil analysis) in high latitude peatlands over the last glacial-interglacial cycle with quantification of carbon sequestration in different environments (i.e., wet vs. drier muskegs). These paleo-peatland histories will provide long-term carbon sequestration records, which can be used for comparisons with paleoclimate reconstructions from the same sediments, as well as ice cores, marine records, and lake stratigraphy. The independent paleoclimate data will be utilized by the new Holocene Peatland Model to simulate coupled carbon and water dynamics of northern peatlands at an annual time step over time scales of decades to millennia. The model-simulated carbon accumulation record can be then compared with the peatland histories, and differences evaluated in terms of plant composition, productivity, and decomposition. This iterative model-data research will provide long-term empirical information necessary to evaluate the role of the hydrological cycle in future wetland carbon cycling, and the past importance of climate and vegetation in sequestering carbon over millennia.The selected sites for new sampling include peatlands of Alaska?s North Slope at Toolik Lake where an extensive ecological database exists as well as the arctic foothills of the western Mesa site. AMS 14C ages, as well as Pb-210 and Cs-137, will be used in conjunction with C and bulk density to determine carbon accumulation for each site. Analysis of bryophyte and isotopes/biomarkers will provide defined moisture regimes as well as possible water chemistry changes due to volcanic ash deposition in these sites. Of particular interest are climatic intervals such as the Bolling-Allerod/Younger Dryas, the early Holocene, the Preboreal and 8200-yr events, mid-Holocene, the Neoglacial, Little Ice Age, and the last 50 years. This project will involve at least 4 undergraduate theses and one postdoc. The PI has a well-documented record of mentoring undergraduates and advising graduate students in field and lab-based programs, with many of her former advisees publishing their results in peer-reviewed journals. Students will have an opportunity to present results at the local, state, and national levels. The group will continue its long leadership in science programs training high school students and teachers at NASA/GISS summer program for minorities and Columbia University?s Department of Earth and Environmental Science graduate and undergraduate students, as well as local outreach to museums and public programs. They intend to engage a K-12 teacher in their field and lab research in the Lamont Doherty Earth Observatory VAST (Visiting Arctic/subarctic Summer Teacher) program for far-ranging impact. Additionally, their analyses can be utilized for the Columbia University courses the PI teaches on Wetlands and Climate Change, Terrestrial Paleoclimate, as well as seminars in Plant Ecology and Paleoecology, and in courses the UNH PI teaches (Biogeochemistry and Environmental Modeling). The results and conclusions of this work will have implications for arctic climate policy, ecosystem management, and education.