CAREER: Past, Present, and Future of the Peatlands of the Caribbean: Implications for the Carbon Cycle in a Changing Climate

热带生态系统是全球土地利用变化和退化速度最快的地区之一。这些生态系统也受到气候变化和气候变暖的影响。土地利用的变化有可能对我们的气候产生重要的反馈，特别是通过碳循环。然而，这些对生态系统的反馈的幅度是不确定的。热带地区的土壤碳尤其如此。对热带土壤中储存的碳的范围和位置以及控制净碳平衡的过程的实地测量仍然很少。这项研究特别关注热带泥炭地，这是一种碳含量非常高的栖息地。目前的地图被认为严重低估了热带湿地(和泥炭地)的面积，导致了不可靠的碳储量估计。同样，整个热带泥炭地复合体的起源、时间和发展历史也鲜为人知，这使得识别和量化泥炭形成的主要控制因素具有挑战性。这些数据和知识差距使得很难预测泥炭地在目前和未来条件下的演变及其相关的碳含量。因此，生态学家不太清楚泥炭在热带条件下形成的地点或原因，以及是什么控制了堆积率。该项目是第一个旨在全面了解加勒比泥炭地起源和发展的项目，将使用广泛的实地调查、详细的泥炭核心数据和综合以及基于过程的计算机模拟。这一职业项目将有助于美国在地球系统科学方面的世界领先专业知识，促进泥炭社区的研究需求，并指导政策和土地管理决策。该研究项目将新的实地工作与古生态和模型研究相结合，并对加勒比海泥炭地的陆地碳平衡进行广泛的学生培训。PI和她的团队将整合1)从尼加拉瓜和哥斯达黎加加勒比海沿岸多个地点收集的新数据，2)来自其他加勒比海泥炭地的现有数据的综合，以及3)基于处理的生态模拟。这个项目解决的首要问题是：什么条件能够启动泥炭地，促进泥炭的发展，并控制泥炭地在十年到千年的时间尺度上的碳平衡？整个研究区域的泥炭矿藏的存在将通过广泛的实地调查来绘制和确认。加勒比泥炭地是如何以及何时形成的，将通过使用详细的泥炭核心数据和综合已公布的记录来确定。将估计碳储量，并研究泥炭形成率与古环境变化之间的关系。利用基于过程的泥炭地模型，将模拟和量化碳固存速率，以阐明加勒比海泥炭地目前的功能，并预测它们未来可能如何响应自然和人为的强迫。总体而言，该项目将对加勒比泥炭地的位置、范围、成因和发展进行首次全面评估。这项工作对于评估热带生态系统过去、现在和未来的弹性是必要的，并有助于为土地管理决策提供信息；它还将允许生态学家对地球系统模型进行基准测试，并测试关于热带泥炭地在全新世全球C周期中的作用的假设。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Tropical ecosystems are subject to some of the highest rates of land-use change and degradation globally. These ecosystems are also being affected by climate variability and warming. Changes in land-use have the potential for important feedbacks on our climate, especially via the carbon cycle. However, the magnitude of these feedbacks on ecosystems are uncertain. This is particularly the case for soil carbon in the tropics. Field measurements of the extent and location of carbon stored in tropical soils, and the processes that control net carbon balance remain sparse. This study specifically looks at tropical peatlands, a very carbon-rich type of habitat. Current maps are believed to significantly underestimate tropical wetland (and peatland) areas resulting in unreliable carbon stock estimates. Likewise, the origin, timing, and developmental history of peatland complexes across the tropics are poorly known, making it challenging to identify and quantify the main controls on peat formation. These data and knowledge gaps make it difficult to predict peatland evolution and their associated carbon content under present and future conditions. As such, ecologists don’t quite understand where or why peat forms under tropical conditions, and what controls accumulation rates. This project is the first to aim at gaining an integrated understanding of the origin and development of Caribbean peatlands, and will use extensive field surveys, detailed peat-core data and synthesis, as well as process-based computer modeling. This CAREER project will contribute to the US world-leading expertise in Earth System Science, advance the peatland community’s research needs, and guide policy and land management decisions.This research project combines new field work with paleoecological and modeling studies as well as extensive student training on the terrestrial carbon balance of Caribbean peatlands. The PI and her team will be integrating 1) new data collection from multiple sites along the Caribbean coast of Nicaragua and Costa Rica, 2) a synthesis of existing data from other Caribbean peatlands, and 3) processed-based ecological simulations. The overarching question this project addresses is: what are the conditions that enable peatland initiation, facilitate peat development, and control peatland C balance over decadal to millennial timescales? The existence of peat deposits across the study region will be mapped and confirmed using extensive field surveys. How and when Caribbean peatlands became established will be determined by using detailed peat-core data and synthesis of published records. C stocks will be estimated, and the relationships between the rate of peat formation and paleoenvironmental change will be examined. Using process-based peatland models, C sequestration rates will be simulated and quantified to elucidate the current function of Carribean peatlands, and forecast how they might respond to natural and anthropogenic forcings in the future. Overall, this project will produce the first comprehensive assessment of the location, extent, genesis, and development of Caribbean peatlands. This work is necessary to assess the past, present, and future resilience of tropical ecosystems and to help inform land management decisions; it will also allow ecologists to benchmark Earth System Models and test hypotheses about the role of tropical peatlands in the Holocene global C cycle.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.