Postdoctoral Fellowship: EAR-PF: Assessing the net climate impact of tropical peatland restoration: the role of methane

泥炭地是全球重要的碳库，其碳储量是全球森林碳库的两倍。排干泥炭地用于农业和林业会鼓励微生物分解泥炭碳，将储存的碳以二氧化碳(CO2)的形式释放到大气中。泥炭地排水在东南亚尤其普遍，那里90%以上的泥炭沼泽受到干扰，导致泥炭地二氧化碳排放量与区域化石燃料排放量相当。堵塞排水渠以提高水位，应该会通过阻止微生物分解来减少二氧化碳排放。因此，通过堵塞运河来实现泥炭地再湿化被认为是一种低成本的自然气候解决方案，包括印度尼西亚在内的许多国家都承诺对大面积退化的泥炭地进行再湿化，以应对气候变化。然而，泥炭地重新湿地会增加甲烷(CH4)的排放，因为产生甲烷的微生物在淹水的条件下茁壮成长。由于甲烷具有很高的全球变暖潜力，增加的甲烷排放可能会部分抵消泥炭地重新湿地的气候好处。对热带泥炭地重新湿润后的二氧化碳和甲烷排放量的测量极其稀少，这是政策和规划的一个主要限制。这项研究旨在量化印度尼西亚湿地泥炭地的甲烷和二氧化碳排放量。Clarice Perryman博士将收集新的排放数据，以评估未来不同热带泥炭湿地湿地情况下温室气体排放的变化，并确定控制湿地湿地排放的重要变量。这项研究的结果将通过确定泥炭地再湿的空间规模和时机来指导泥炭地管理，这将提供最大的温室气体减排。研究成果将通过公开介绍和研究出版物向当地社区、伙伴非政府组织和研究界广泛传播。Perryman博士还致力于通过在印度尼西亚和她所在的机构指导本科生和研究生的相关研究，促进地球科学的归属感、可获得性、正义、公平、多样性和包容性(BAJEDI)。泥炭湿地重新湿地作为一种有效和低成本的自然气候解决方案越来越受欢迎，因为重新湿地可以减少用于农业和伐木的泥炭地的高二氧化碳排放。尽管复湿减少了二氧化碳排放，但复湿后CH4排放量的增加可能会导致重新湿化的泥炭地在几十年内仍然是净温室气体源，具有净正(变暖)辐射强迫。尽管泥炭湿地具有巨大的潜力和广泛的热情，但对泥炭湿地温室气体排放的实地测量极其稀少。东南亚的热带泥炭地尤其如此，包括印度尼西亚的那些国家，印尼最近承诺对大片退化的泥炭地进行重新湿化，以减少野火风险和二氧化碳排放。这项研究将量化印度尼西亚湿地泥炭地的甲烷和二氧化碳排放量。Clarice Perryman博士将利用这一新数据将排放量从地块提升到景观水平，以评估未来温室气体排放和净气候影响在不同的热带泥炭湿地重新湿化情景中的差异。这位研究员将测量印度尼西亚泥炭地在安装排水渠堵塞之前和之后的二氧化碳和甲烷排放量，以评估从每天到每年的排放。Perryman博士将利用现有的地理空间数据集，在与将排放扩大到地貌水平相关的地块尺度上，确定控制CH4排放的非生物(例如水文学、地球化学)和生物(例如植被、微生物群落组成)因素。最后，这位研究员将应用这些新数据和过程级别的见解来评估热带泥炭地重新湿化在十年到世纪尺度上的净气候影响。使用各种方法，包括直接排放测量、稳定同位素测量和微生物组分析，这项研究将改进对介导CH4循环的微生物系统将如何响应热带泥炭地土地利用变化的预测。这项研究将提供来自湿地的热带泥炭地CH4和CO2排放及其非生物和生物控制的关键数据集。Perryman博士将与印度尼西亚的社区和合作伙伴非政府组织一起参与知识的联合生产和转移，并通过在印度尼西亚和她所在的学院指导本科生和研究生进行相关研究来推广BAJEDI。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。

Peatlands are globally important carbon stores, containing double the amount of carbon stored in forests worldwide. Draining peatlands for agriculture and forestry encourages microbial decomposition of peat carbon, releasing this stored carbon into the atmosphere as carbon dioxide (CO2). Peatland drainage is particularly widespread in Southeast Asia, where over 90% of peat swamps have been disturbed, resulting in peatland CO2 emissions on par with regional fossil fuel emissions. Blocking drainage canals to raise water levels should reduce CO2 emissions by discouraging microbial decomposition. As such, “peatland rewetting” through canal blocking has been proposed as a low-cost natural climate solution and many countries including Indonesia have committed to rewetting vast areas of degraded peatlands to combat climate change. However, peatland rewetting stands to increase methane (CH4) emissions, as microbes that produce CH4 thrive under water-logged conditions. Increased CH4 emissions may partially offset the climate benefits of peatland rewetting due to the high global warming potential of CH4. Measurements of CO2 and CH4 emissions after rewetting tropical peatlands are extremely scarce, which is a major limitation for policy and planning. This research aims to quantify CH4 and CO2 emissions from rewetted peatlands in Indonesia. Dr. Clarice Perryman will collect new emissions data to assess how future greenhouse gas emissions vary across different tropical peatland rewetting scenarios and identify important variables controlling emissions from rewetted peatlands. The results of this research will help guide peatland management through determining the spatial scale and timing of peatland rewetting that will provide greatest greenhouse gas emissions reductions. Research findings will be broadly disseminated to local communities, partner NGOs, and the research community via public presentations and research publications. Dr. Perryman also aims to promote belonging, accessibility, justice, equity, diversity, and inclusion (BAJEDI) in the geosciences through mentoring undergraduate and graduate students on related research in Indonesia and at her host institution. Peatland rewetting is gaining popularity as an effective and low-cost natural climate solution as rewetting stands to reduce high CO2 emissions from peatlands drained for agriculture and logging. Even though rewetting reduces CO2 emissions, increased CH4 emissions post-rewetting can cause rewetted peatlands to remain a net greenhouse gas source with a net positive (warming) radiative forcing for several decades. Despite the great potential and widespread enthusiasm for peatland rewetting, field measurements of greenhouse gas emissions from rewetted peatlands are extremely sparse. This is particularly true for tropical peatlands in Southeast Asia, including those in Indonesia which has recently committed to rewetting vast areas of degraded peatlands to mitigate wildfire risks and CO2 emissions. This research will quantify CH4 and CO2 emissions from rewetted peatlands in Indonesia. Dr. Clarice Perryman will use this new data to upscale emissions from plot to landscape level to assess how future greenhouse gas emissions and net climate impact vary across different tropical peatland rewetting scenarios. The fellow will measure CO2 and CH4 emissions at peatland sites in Indonesia before and after drainage canal blocks are installed to assess emissions at sub-daily to annual timescales. Dr. Perryman will determine abiotic (e.g. hydrology, geochemistry) and biotic (e.g. vegetation, microbial community composition) factors controlling CH4 emissions at the plot scale relevant to upscaling emissions to landscape-level using existing geospatial datasets. Finally, the fellow will apply these new data and process-level insights to assess the net climate impact of tropical peatland rewetting at decadal to century scales. Using a variety of methods, including direct emissions measurements, stable isotope measurements, and microbiome analyses, this research will improve predictions of how microbial systems mediating CH4 cycling will respond to land use change in tropical peatlands. The research will provide critical datasets of CH4 and CO2 emissions and their abiotic and biotic controls from rewetted tropical peatlands. Dr. Perryman will engage in knowledge co-production and transfer with communities and partner NGOs in Indonesia and promote BAJEDI through mentoring undergraduate and graduate students on related research in Indonesia and at her host institution.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.