Changes in soil-microbe-exoenzyme C:N:P stoichiometry along an altitudinal gradient in Mt. Datudingzi,Northeast China |
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| Affiliation: | Center for Ecological Research, Northeast Forestry University, Harbin 150040, China; and Key Laboratory of Sustainable Forest Ecosystem Management—Ministry of Education, Northeast Forestry University, Harbin 150040, China |
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| Abstract: | Aims Altitude-induced changes in temperature, moisture, vegetation types and other conditions would significantly affect soil carbon (Csoil), nitrogen (Nsoil), phosphorus (Psoil) concentrations and their stoichiometry. How soil microorganisms adapt to the variability of soil resource stoichiometry by regulating their biomass and extracellular enzymatic stoichiometry remains uncertain. The objective of this study was to quantify the altitudinal trends of soil-microbe-exoenzyme C:N:P stoichiometry and to explore the correlations among soil-microbe- exoenzyme stoichiometry.Methods In the present study, we investigated the Csoil, Nsoil, Psoil concentrations, microbial biomass C (Cmic), N (Nmic), P (Pmic) concentrations, and the activities of C (β-1,4-glucosidase, BG), N (N-acetyl-β-glucosaminidase, NAG), and P (acid phosphatase) acquiring extracellular enzymes for microorganisms in four ecosystems along an altitudinal gradient on Mt. Datudingzi, Northeast China. These four ecosystems are a mixed broadleaf-coniferous forest at 800 m, a coniferous forest at 1 100 m, a Betula ermanii forest at 1 600 m and a grassland at 1 700 m.Important findings The results showed that: (1) altitude had no significant effect on Csoil and Cmic concentrations but had significant effects on soil and microbial biomass N and P concentrations. (2) The activities of BG and NAG decreased significantly with increasing altitude, likely due to the high elevation induced low temperature that inhibits microbial activities. (3) Altitude had significant effects on soil C:N, microbe C:N:P, and exoenzyme C:N:P; exoenzyme C:N:P decreased with the increasing stoichiometric imbalances between microorganisms and soils (ratios of soil C:N:P to microbe C:N:P, respectively). Overall, these results suggested that microorganisms can adapt to the variability of soil C:N:P by regulating their biomass C:N:P and exoenzyme C:N:P, and supported the microbial resource allocation theory. |
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| Keywords: | stoichiometry microbial activity C:N:P altitude extracellular enzyme |
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