Carbon in Permafrost Experimental Heating Research (CIPEHR) project: Foliar mineral element concentrations, stocks, and annual litterfall fluxes in July 2009 and 2017

In this study, we are asking the question: how permafrost degradation may influence foliar mineral element cycling with changing subarctic tundra vegeatation? We are answering this question by using a combination of field measurements (aboveground biomass, foliar biomass, foliar net primary productivity (NPP)) and laboratory measurements (mineral element foliar concentration: Al, Ca, Fe, K, Mn, P, S, Si, and Zn) to evaluate the mineral element foliar stocks and the mineral element foliar fluxes upon annual litterfall. We covered 5 vascular plant species from an established tundra field site near Healy, Alaska in the foothills of the Alaska Range. Field measurements center on at a warming experiment located in an upland tundra field site near Healy, Alaska in the foothills of the Alaska Range. Elemental analyses of plant species typical from the moist acidic tundra (in 2009 and 2017), combined with relative aboveground biomass and NPP measurements, brought key information on the influence of permafrost degradation and the vegetation composition on the litter elemental composition, and thereby the plant nutrient cycling across the subarctic tundra.

本研究提出核心科学问题：随着亚北极冻原植被发生变化，多年冻土退化会如何影响叶片矿质元素循环？为解答该问题，本研究结合野外测量与实验室分析开展研究：野外测量指标涵盖地上生物量、叶片生物量、叶片净初级生产力（NPP）；实验室分析则测定叶片矿质元素浓度，包括铝（Al）、钙（Ca）、铁（Fe）、钾（K）、锰（Mn）、磷（P）、硫（S）、硅（Si）与锌（Zn），以此评估年凋落物输入过程中的叶片矿质元素库与叶片矿质元素通量。本研究在阿拉斯加山脉山麓希利附近一处已建成的冻原野外站点，选取了5种维管植物物种开展研究，野外测量工作聚焦于该站点内高地冻原区域的增温实验。通过对湿润酸性冻原典型植物物种（2009年与2017年采样）的元素分析，结合相对地上生物量与NPP测量结果，本研究获取了多年冻土退化与植被组成对凋落物元素组成的影响相关关键信息，进而阐明了亚北极冻原全域的植物养分循环过程。