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，但在给定的一年中，新根的动态生产可以占森林林分碳分配的75%。因此，根系的周转量是全球碳循环的重要贡献，但相对而言，人们对土壤剖面中这一过程是如何发生的知之甚少。该项目将调查位于600公里南北向的三个刺松生态系统中细根的寿命和周转，以提供温度梯度。细小的根系动态将被观察到用微型电子控制系统，该系统利用一个小型摄像机，将其放置在插入地面的透明管中。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，本项目将研究不同直径的根类对土壤剖面中不同深度的碳周转的作用，以了解这些非常小直径的根类的功能。为了进一步了解根的功能，将对选定的根进行x射线微探针分析，以跟踪根表面的金属轮廓。

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.