EAR-PF: Plant Wax Transport and Integration Through the Late Holocene in Guatemala

韦斯利帕克博士已被授予NSF博士后奖学金，在麦吉尔大学彼得道格拉斯博士的指导下开展研究和教育计划。中美洲雨林正在以惊人的速度消失，这对区域降水量、自然资源可用性和全球碳循环产生了重大影响。预计这些环境变化今后将继续下去，对中美洲各地的人类和生态社区产生不利影响。因此，调查不断变化的植被和降水情况将补充和扩大有关热带森林自然变异的知识，并限制人类活动对这些濒危森林的影响。拟议的研究将分析保存在危地马拉湖盆沉积物岩心中的现代植物蜡（丰富且持久的碳氢化合物分子），以调查中美洲现代热带森林中植物蜡的地理空间运输和整合。研究结果将建立一个9,000年的碳和氢同位素变化概况，这将有助于了解植被和降水的长期变化。这项假设驱动的研究将测试中美洲植被类型变化可以通过植物蜡分析进行评估的想法，并且植物蜡将准确跟踪西半球的气候扰动。该项目将与危地马拉当地的保护团体合作进行，以帮助他们的活动，并将与美国，加拿大和危地马拉的社区教育计划相结合。研究分两个阶段进行。首先，氢和碳同位素的长链植物蜡（正烷基脂质）从现代叶材料和沉积物进行了分析，使用化合物特定的同位素分析，以表征植物蜡的运输途径和植被平衡（C3/C4植物比）在伊萨瓦尔湖和佩滕盆地的危地马拉。然后，植物蜡从沉积物芯覆盖9,000年的分析，重建植被和降水的变化，通过中，晚全新世在两个盆地。这些植物蜡衍生的同位素配置文件，然后比较独立的代理数据，以确定已知的全新世气候事件（如8.2 kyr事件）的信号，并跟踪这些信号在热带中美洲的幅度。这项研究通过生成焦点盆地的第一个全新世中晚期氢和碳同位素剖面，提高了中美洲正在进行的古气候研究的整体质量和适用性。这项研究可以为负责制定和实施区域保护和气候适应战略的政策制定者提供信息，这些战略将有利于中美洲的人口，生态系统和金融投资。这项研究的其他更广泛的影响包括在美国，加拿大和危地马拉的推广教育活动。该项目获得了古气候变化展望项目地球科学部分的共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Dr. Wesley Parker has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans under the mentorship of Dr. Peter Douglas at McGill University. The rainforests of Central America are being lost at an alarming rate, and this has significant impacts on regional precipitation, natural resource availability, and the global carbon cycle. These environmental changes are expected to continue in the future, adversely impacting both human and ecological communities across Central America. Therefore, investigation of changing vegetation and precipitation regimes will complement and expand knowledge surrounding natural variability in tropical forests and constrain the impacts of human activities on these endangered forests. The proposed research will analyze modern plant waxes (abundant and long-lasting hydrocarbon molecules) preserved in sediment cores from lake basins in Guatemala to investigate geospatial transport and integration of plant waxes in the modern tropical forests of Central America. The results will establish a 9,000 year profile of carbon and hydrogen isotope variability that will develop knowledge surrounding long-term changes in vegetation and precipitation. This hypothesis driven research will test the ideas that changing vegetation types in Central America can be assessed through plant wax analysis, and that plant waxes will accurately track climate perturbations in the Western Hemisphere. This project will be conducted in collaboration with local conservation groups in Guatemala to help inform their activities and will be coupled with community education programs in the USA, Canada, and Guatemala. The research is accomplished in two phases. First, the hydrogen and carbon isotopes in long-chained plant waxes (n-alkyl lipids) from modern leaf material and sediments are analyzed using compound specific isotope analyses to characterize plant wax transportation pathways and vegetation balance (C3/C4 plant ratio) in the Lake Izabal and Petén Basins of Guatemala. Then, plant waxes retrieved from sediment cores covering 9,000 years are analyzed to reconstruct changes in vegetation and precipitation through the middle and late Holocene in both basins. These plant wax-derived isotope profiles are then compared to independent proxy data to identify signals of known Holocene climate events (e.g. 8.2 kyr event) and track the magnitude of these signals in tropical Central America. This research enhances the overall quality and applicability of ongoing paleoclimatic research in Central America by generating the first middle and late Holocene hydrogen and carbon isotope profiles for the focal basins. This research can inform policymakers responsible for the generation and implementation of regional conservation and climate adaptation strategies that will benefit human populations, ecological systems, and financial investments in Central America. Additional broader impacts of this research include outreach educational activities in the USA, Canada, and Guatemala. This project received co-funding from the Earth Science section of the Paleo Perspectives on Climate Change program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.