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Pedosphere 20(4): 427--435, 2010
ISSN 1002-0160/CN 32-1315/P
©2010 Soil Science Society of China
Published by Elsevier B.V. and Science Press

Microbial activity in a temperate forest soil as affected by elevated atmospheric CO₂

ZHENG Jun-Qiang, HAN Shi-Jie

, ZHOU Yu-Mei, REN Fei-Rong, XIN Li-Hua and ZHANG Yan

Forestry Center, Institute of Applied Ecology, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

ABSTRACT

Microorganisms play a key role in the response of soil ecosystems to the rising atmospheric carbon dioxide (CO₂) as they mineralize organic matter and drive nutrient cycling. To assess the effects of elevated CO₂ on soil microbial C and N immobilization and on soil enzyme activities, in years 8 (2006) and 9 (2007) of an open-top chamber experiment that begun in spring of 1999, soil was sampled in summer, and microbial biomass and enzyme activity related to the carbon (C), nitrogen (N) and phosphorus (P) cycling were measured. Although no effects on microbial biomass C were detected, changes in microbial biomass N and metabolic activity involving C, N and P were observed under elevated CO₂. Invertase and dehydrogenase activities were significantly enhanced by different degrees of elevated CO₂. Nitrifying enzyme activity was significantly (P < 0.01) increased in the August 2006 samples that received the elevated CO₂ treatment, as compared to the samples that received the ambient treatment. Denitrifying enzyme activity was significantly (P < 0.04) decreased by elevated CO₂ treatments in the August 2006 and June 2007 (P < 0.09) samples. β-N-acetylglucosaminidase activity was increased under elevated CO₂ by 7% and 25% in June and August 2006, respectively, compared to those under ambient CO₂. The results of June 2006 samples showed that acid phosphatase activity was significantly enhanced under elevated CO₂. Overall, these results suggested that elevated CO₂ might cause changes in the belowground C, N and P cycling in temperate forest soils.

Key Words: CO₂ enrichment, microbial biomass, soil carbon cycling, soil nitrogen cycling

Citation: Zheng, J. Q., Han, S. J., Zhou, Y. M., Ren, F. R., Xin, L. H. and Zhang, Y. 2010. Microbial activity in a temperate forest soil as affected by elevated atmospheric CO₂. Pedosphere. 20(4): 427-435.

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