Role of fine roots in nutrient uptake and turnover for boreal ecosystems

森林生态系统中四分之一的生物量可以在地下找到，但新根的动态生产可以占到给定年份森林中碳分配的75%。 因此，根的周转是对全球碳循环的重要贡献，但相对较少的是知道这是如何发生在土壤剖面。该项目将调查位于南北600公里的三个短叶松生态系统内细根的寿命和周转率，以提供温度梯度。细根动态将观察一个minirrectron系统，它利用一个小的视频摄像机，被放置在透明管插入地面。通过每月观察根系图像，我们将能够确定根系产量和死亡率，并估计根系寿命。更重要的是，这个拟议的项目将研究不同直径的根类在土壤剖面不同深度的碳周转的作用，以了解这些非常小的直径类的根功能。 为了进一步了解牙根功能，将对选定的牙根进行X射线微探针分析，以跟踪牙根表面的金属轮廓。

A quarter of the biomass in a forest ecosystem can be found belowground but the dynamic production of new roots can account for up to 75% of the carbon allocation in a forest stand in a given year.  Thus the turnover of roots is an important contribution to the global carbon cycle, yet relatively little is know how this occurs within the soil profile. This project will investigate the longevity and turnover of fine roots within three jack pine ecosystems located across a 600 km N-S to provide a temperature gradient. Fine root dynamics will be observed with a minirhizotron system which utilizes a small video camera that is placed into clear tubes inserted in the ground. By observing root images on a monthly basis we will be able to determine root production and mortality and estimate root longevity. More importantly, this proposed project will examine the role of different diameter root classes to carbon turnover at different depths in the soil profile in order to understand root functionality for these very small diameter classes.  To further understand root functionality, selected roots will be subjected to x-ray microprobe analysis to follow metal profiles on the root surfaces.