CAREER: Detecting warming impacts on carbon accumulation across a climate transect of Michigan peatlands

职业：检测变暖对密歇根泥炭地气候断面碳积累的影响

• 批准号: 2338357
• 负责人: Michael Philben
• 金额: $ 50.78万
• 依托单位: Hope College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-01 至 2029-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2338357&HistoricalAwards=false
• 关键词: CAREER; Detecting; warming; impacts; carbon

This CAREER project will investigate how increases in temperature will affect the carbon (C) cycle in peatlands. Peatlands are wetland ecosystems that naturally store C due to very slow decomposition of plant material, and thus now store a massive amount of C as organic matter. How the C cycle in these peatlands will change as climate warms is unknown. Michigan is positioned at the southern end of the range of boreal (northern) peatlands, which means that Michigan peatlands will be among the first to be affected by warming. This project will establish a climate transect of peatlands to help predict how future warming will affect the C stored in these ecosystems. The transect contains seven sites, from Portage in the south to Newberry in Michigan’s Upper Peninsula. The sites span 5°C in average temperature, which is approximately equivalent to the warming expected over the next century. The project will exploit these natural differences in temperature to determine how C cycle processes in peatlands will change with warming. In addition, a new course for first-year undergraduate students will be developed, centered around a field trip to sites on the peatland transect in the week before the start of classes, to train and inspire the next generation of environmental scientists.The net C balance of the peatland ecosystem is determined by the net balance of C inputs (from plant growth) and C losses (through microbial decomposition of organic matter). Predicting future changes in the C balance has proved difficult because both of these fluxes are expected to increase with warming. C losses will be evaluated by measuring carbon dioxide and methane emissions from the soil, as well as litter bag decomposition experiments. Changes in C inputs via plant growth will be mediated by nitrogen (N) availability, due to the strong N limitation of peatland ecosystems. Therefore, the temperature sensitivity of N mineralization will be assessed in field measurements across the transect. Finally, the effects of warming on net C accumulation will be assessed using a geochemical approach, taking advantage of the 1°C of warming that Michigan has already experienced. The long-term accumulation rate will be compared to the recent accumulation rate, using computer modeling to account for organic matter included in the recent rate that is still undergoing aerobic decomposition. This will allow direct testing of the hypothesis that warming has already begun to slow down peat accumulation in marginal peatlands at the southern edge of their climate window. Together, these approaches will provide a complete picture of how C inputs and losses from peatlands will change in response to the warming expected over the coming decades.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.

该职业项目将研究温度升高如何影响泥炭地的碳 (C) 循环。泥炭地是一种湿地生态系统，由于植物材料的分解非常缓慢，因此可以自然储存碳，因此现在可以以有机物的形式储存大量的碳。随着气候变暖，这些泥炭地的碳循环将如何变化尚不清楚，密歇根州位于北方（北部）泥炭地范围的南端，这意味着密歇根州泥炭地将是最先受到影响的地区之一。该项目将建立泥炭地气候横断面，以帮助预测未来变暖将如何影响这些生态系统中储存的碳。该横断面包含七个地点，从南部的波蒂奇到密歇根州上半岛的纽伯里。这些地点的跨度为 5°C。该项目将利用这些自然温度差异来确定泥炭地的碳循环过程将如何随着变暖而变化。学生将得到发展、集中课程开始前一周，围绕泥炭地样带地点进行实地考察，以培训和激励下一代环境科学家。泥炭地生态系统的净碳平衡由碳输入的净平衡（来自植物预测碳平衡的未来变化已被证明是困难的，因为这两种通量预计都会随着变暖而增加，而碳损失将通过测量二氧化碳和甲烷排放来评估。土壤，如由于泥炭地生态系统对氮的强烈限制，植物生长引起的碳输入变化将受到氮（N）可用性的调节，因此，将在整个区域的现场测量中评估氮矿化的温度敏感性。最后，将利用地球化学方法评估变暖对净碳积累的影响，利用密歇根州已经经历的 1°C 变暖，将长期积累率与近期积累率进行比较。使用计算机建模来解释包括在近期速率中的仍在进行有氧分解的有机物，这将允许直接检验这样的假设：变暖已经开始减缓气候窗口南缘边缘泥炭地的泥炭积累。未来几十年泥炭地的碳输入和损失将如何变化以应对未来几十年预期的变暖，这反映了 NSF 的法定使命，并且通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。