Microbial respiration in laboratory soil incubations, Agashashok River, Alaska, 2019

The position of the Arctic treeline is an important regulator of surface energy budgets, carbon cycling and subsistence resources in high latitude environments. It has long been thought that temperature exerts a direct control on growth of treeline trees and the position of the treeline. However, our recent work on white spruce in the Arctic suggests that indirect effects of temperature on tree access to soil nutrients may be of equal or greater importance. Our recent results provide correlative evidence of the importance of winter snow depth as a driver of tree growth. The aim of this project was to experimentally isolate the importance of snow depth and soil nutrient availability and examine the consequences for microbial processes, tree growth and treeline advance. This dataset contains measurements of microbial respiration made over time during a 3-month laboratory incubation in which soils were held at a range of temperatures (-10, -6, -2, 2 and 6 degrees Celsius (deg C)) crossed with a range of labile carbon additions (0, 0.2, 0.4 and 2 milligrams of carbon per gram of dry soil (mg C per g dry soil)).

北极林线（Arctic treeline）的位置是高纬度环境中调控地表能量收支、碳循环与生存资源的关键因子。长期以来，学界普遍认为温度对林线树木的生长及林线位置具有直接调控作用。然而，我们近期针对北极白云杉（white spruce）的研究表明，温度对树木获取土壤养分的间接影响，其重要性或可与温度的直接作用相当，甚至更为显著。我们的近期研究结果提供了相关性证据，表明冬季积雪深度是驱动树木生长的重要因素。本项目旨在通过实验厘清积雪深度与土壤养分有效性的相对重要性，并探究二者对微生物过程、树木生长及林线扩张的影响。本数据集包含了为期3个月的实验室培养过程中，随时间序列获取的微生物呼吸（microbial respiration）测量数据。实验设置了-10、-6、-2、2和6摄氏度（℃）的温度梯度处理，并搭配了每克干土0、0.2、0.4和2毫克碳（mg C per g dry soil）的易变碳（labile carbon）添加梯度，二者采用交叉实验设计。