PostDoctoral Research Fellowship

近地表富含冰的永久冻土的退化可能会向北极和亚北极生态系统释放大量的水，植物将在多大程度上通过新的根生长到前永久冻土层中来利用和蒸腾水，目前尚不清楚。确定植物的作用，影响水的命运，从退化的冻土是重要的限制土壤水分和能量平衡模型中的蒸散量的估计。初步数据显示，植物物种利用永冻层水分的能力各不相同。本次调查的目的是量化新的根生长到前永冻土层和量化使用的永冻土来源的水不同的植物物种通过比较有和没有永冻土的网站。将测量从阿拉斯加针叶林生态系统中收集的活动层、永久冻土和植物茎中的水的氢和氧同位素。贝叶斯逆模型将用于确定不同物种使用的水源，以及它们如何随活动层厚度的季节变化而变化。这项研究将有助于了解永久冻土退化的后果，以及亚北极水循环、能量平衡和对气候的潜在反馈的植物用水变化。拟议的工作得到博士后奖学金的支持，该奖学金将促进多个合作，并将使首席研究员（PI）能够启动她在北极生态系统生态学方面的第一个全面研究计划。PI将接受贝叶斯统计、亚北极生态系统生态学、永久冻土和水文科学以及科学教育和宣传方面的培训。将在阿拉斯加费尔班克斯大学北方博物馆为高中教师举办一个讲习班，旨在将北极地区生态纳入课程。

Degradation of near surface ice-rich permafrost may release a large amount of water to arctic and subarctic ecosystems, and the degree to which plants will use and transpire the water via new root growth into former permafrost horizons is not known. Determining the role of plants in affecting the fate of water from degrading permafrost is important for constraining estimates of evapotranspiration in models of soil moisture and energy balance. Preliminary data show that plant species vary in their ability to use permafrost-derived water. The objective of this investigation is to quantify new root growth into former permafrost horizons and quantify the use of permafrost-derived water by different plant species by comparing sites with and without permafrost. Hydrogen and oxygen isotopes of water from the active layer, permafrost, and plant stems collected in taiga ecosystems in Alaska will be measured. Bayesian inverse modeling will be applied to determine water sources used by different species and how they vary with seasonal changes in active layer thickness. The study will contribute to understanding the consequences of permafrost degradation and changes in plant water use for subarctic water cycling, energy balance, and potential feedbacks to climate. The proposed work is supported by a Post-doctoral Fellowship that will foster multiple collaborations and will enable the principal investigator (PI) to initiate her first full-scale research program in arctic ecosystem ecology. The PI will be trained in Bayesian statistics, ecology of subarctic ecosystems, permafrost and hydrological science, and science education and outreach. A workshop for high school teachers aimed at integrating sub-Arctic ecology into the curriculum will be held at the Museum of the North, University of Alaska Fairbanks.