Eight Mile Lake (EML)_AK_Thaw gradient soil temeprature

In this larger study, we are asking the question: Is old carbon that comprises the bulk of the soil organic matter pool released in response to thawing of permafrost? We are answering this question by using a combination of field and laboratory experiments to measure net carbon exchange, radiocarbon isotope ratios in soil organic matter, soil respiration, and dissolved organic carbon, in tundra ecosystems. The objective of these proposed measurements is to develop a mechanistic understanding of the SOM sources contributing to C losses following permafrost thawing. We are making these measurements at an established tundra field site near Healy, Alaska in the foothills of the Alaska Range. Field measurements center on a natural experiment where permafrost has been observed to warm and thaw over the past several decades. This area represents a gradient of sites, each with a different degree of change due to permafrost thawing. In this area, we eatablished three sites with different degrees of disturbance from the permafrost thaw: 1) a relatively undisturbed tussock tundra (Minimal Thaw site), 2) a site adjacent to to the borehole which is monitoring permafrost thaw since 1985 with intermediate degree of disturbance (Moderate thaw site) and 3) a site where permafrost thaw apeared to have started more than three decades ago (Extensive thaw site) As such, this area is unique for addressing questions at the time and spatial scales relevant for change in arctic ecosystems. This data set includes soil temperature at multiple depths in the profile at three different locations within each one of the three sites described.

在本大型研究中，我们提出核心科学问题：占土壤有机质（Soil Organic Matter）库主体的古老碳，是否会因永久冻土融化而被释放？本研究结合野外实验与室内实验，通过测定苔原生态系统的净碳交换量、土壤有机质中的放射性碳同位素比值、土壤呼吸速率以及溶解性有机碳，解答上述问题。本次拟开展的测量工作，目标是深入理解永久冻土融化后，土壤有机质来源对碳流失的贡献机制。我们将在阿拉斯加山脉山麓、阿拉斯加州希利附近一处已建成的苔原野外站点开展上述测量工作。野外实验以一项天然实验为核心：该区域内永久冻土在过去数十年间持续增温并发生融化。该区域包含一系列梯度分布的样地，各样地因永久冻土融化产生的变化程度各不相同。在该区域内，我们设置了3处受永久冻土融化干扰程度各异的样地：1）相对未受干扰的草丘苔原样地（轻度融化样地）；2）毗邻自1985年起开展永久冻土融化监测的钻孔、受干扰程度中等的样地（中度融化样地）；3）永久冻土融化于三十余年前便已启动的样地（重度融化样地）。因此，该区域具备独特的研究条件，可在与北极生态系统变化相关的时间与空间尺度上解答相关科学问题。本数据集涵盖上述3处样地中，每处样地内3个不同点位的土壤剖面多深度温度数据。