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Volume 39, Number 3, June 2006

Seasonal variation of microbial ecology in hemlock soil of Tatachia Mountain, Taiwan


Shang-Shyng Yang, Shu-Hsien Tsai, Hsiao-Yun Fan, Chiun-Kai Yang, Wei-Lan Hung, Shine-Tsern Cho
Department of Biochemical Science and Technology and Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan

Received: September 13, 2005    Revised: October 26, 2005    Accepted: November 13, 2005   

 

Corresponding author:

Professor Shang-Shyng Yang, Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan. E-mail: ssyang@ntu.edu.tw This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

 



 

Background and purpose: 

Forest soil microorganisms and fauna decompose the organic materials, and thus strongly influence the nutrient cycling of the ecosystem. Soil microorganisms also contribute to soil structure and soil fertility. In Taiwan, the microbial distributions of soils have only been determined in acidic soil, inorganic acidic soil, upland soil, alkaline soil and power plant areas. There are few data on the microbial populations of forest soils. Tatachia Mountain is located in the central part of Taiwan and is a typical high altitude protected ecosystem area, designated as a National Park. This study investigated the role of microorganisms in the ecology and nutrient transformation of forest soil in Taiwan.

 



 

Methods:

As part of long-term ecological research in Taiwan, the environmental conditions, seasons, microbial populations, biomass and organic acid contents of hemlock soil were investigated. We also studied the effect of depth on microbial populations and biomass.

 



 

Results:

The soil temperatures were between 5.5 and 15.6º C and the soil pH ranged from 3.3 to 4.4. Total organic carbon and total nitrogen contents ranged from 2.3 to 37.1% and from 0.3 to 1.7%, respectively. The carbon/nitrogen ratio was between 8.2 and 24.4. In topsoil, each gram of soil contained 105-107 colony-forming units (CFU) culturable bacteria, 102-105 CFU actinomycetes, 103-105 CFU fungi, 104-106 CFU cellulolytic microbes, 104-106 CFU phosphate-solubilizing microbes, and 103-106 CFU nitrogen-fixing microbes. Microbial populations were higher in topsoil compared with subsoil, but lower in topsoil than in organic layer. Microbial populations also decreased with the depth of soil. Microbial populations at 1E horizon were 0.6% to 9.4% of those at O horizon. The microbial biomass evaluated contained carbon 391-1013 μg, nitrogen 51-146 μg, malic acid 76-557 nM and succinic acid 37-527 nM per gram of soil. Summer season had higher microbial populations, biomass and organic content than winter season, but the differences were not significant.

 



 

Conclusion:

Heavy coverage of organic matter was found in hemlock and spruce soils and was associated with acidic pH. Microbial populations decreased with increasing soil depth. Microbes play a very important role in organic matter decomposition and nutrition transformation in hemlock soil.

 



 

Key words:

Biomass, ecosystems, seasons, soil microbiology, trees



 



 

J Microbiol Immunol Infect 2006;39:195-205.