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Effect of disturbed and undisturbed soils on the carbon assimilation capacity of autotrophic microbes.

WU Hao1,2, JIAN Yan2, GE Ti-da2, WANG Jiu-rong2, YUAN Hong-zhao2, TAN Li-min1, LI Ke-lin1**, WU Jin-shui2   

  1. (1 College of Forestry, Central South University of Forestry and Technology, Changsha 410004, China; 2 Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China)
  • Online:2014-06-10 Published:2014-06-10

Abstract:

Assimilation of atmospheric carbon dioxide (CO2) by autotrophic microbes is an integral process in the soil environment. However, the influence of disturbed and undisturbed soils on CO2assimilation capacity remains poorly understood. In this study, we incubated four types of disturbed and undisturbed soil samples for 110 days in a closed, continuously 14Clabeled CO2 atmosphere and measured the amount of 14Clabeled carbon (C) incorporated in the microbial biomass during this period. The allocation of 14Clabeledassimilated C in labile soil C pools such as dissolved organic C (DOC) and microbial biomass C (MBC) was analyzed over the 14Clabeling span. Significant amounts of 14C-SOC were detected in both disturbed and undisturbed soils. The assimilative rate ranged from 0.015 to 0.148 g·m-2·d-1 in the disturbed soils and from 0.007 to 0.050 g·m-2·d-1 in the undisturbed soils. A significant positive linear relationship was detected between the concentrations of 14C-SOC and 14C-MBC (R2=0.955, P<0.01). The proportions of 14C-DOC, 14C-MBC, and 14C-SOC to the total DOC, MBC, and SOC were 0.9%-4.5%, 2.2%-9.7%, and 0.09%-0.43% in the undisturbed soils, and 0.26%-1.09%, 3.6%-20%, and 2.9%-5.7% in the disturbed soils, respectively. Furthermore, the distribution and transformation of microbeassimilated C had much greater influence on the dynamics of DOC and MBC than on those of SOC. These results offer new insights into the importance of microbes in the assimilation of atmospheric CO2 and of the potentially significant contributions made by microbial autotrophy to terrestrial C cycling.
 

Key words: bamboo forest, habitat, correlation analysis, potential habitat, population