泥炭沼泽土壤酶活性对水热条件变化的响应及其与CO_2释放通量的关系——以小兴安岭地区为例

采用实验室培养的方法,研究了小兴安岭地区两类典型的泥炭沼泽:苔草型泥炭沼泽和泥炭藓型泥炭沼泽中几种水解酶活性(β-葡萄糖苷酶、酚氧化酶)对不同温度和水位变化的响应,以及与CO_2释放通量的相瓦关系.结果表明:β-葡萄糖苷酶活性在两类泥炭沼泽中受多种因素制约,在一定湿度范围内受水位控制较明显,当土壤湿度降低到一定程度时,温度对土壤酶活性影响增强.酚氧化酶活性与温度密切相关,但对温度变化的响应存在明显的季节性差异.相对而言,苔草型泥炭沼泽中β-葡萄糖苷酶和酚氧化酶活性显著高于相同培养条件下泥炭藓型泥炭沼泽.总体上,苔草型泥炭沼泽中水解酶活性较泥炭藓型泥炭沼泽中高,但是其CO_2释放通量却低于泥炭鲜型泥炭沼泽,表明与有机碳分解有关的水解酶的活性高低不能作为解释泥炭沼泽CO_2释放通量大小的唯一指标.

The responses of enzyme activities to temperature and water level changes and the relationship between enzyme activity and CO_2 emission flux in peatlands: A case study in Xiao'Xing'An'Ling mountain area.

The responses of two enzyme activities, p-glucosidase and phenol oxidase, to temperature and water level changes, and the relationship between the enzyme activity and CO_2 emission flux in two typical peatlands, marsh and bog, which located in Xiao'Xing'An'Ling mountain area, were investigated with laboratory incubation experiments. The results indicated that soil enzyme activities were affected by confounding factors. The activities of p-glucosidase were regulated mainly by water level within limits. Further more, the activities of p-glucosidase were regulated more by temperature in peatlands with soil moisture decreasing. The effect of temperature on the activity of phenol oxidase was remarkable, but exhibited obviously seasonal variations. In comparison, the activities of P-glucosidase and phenol oxidase were higher in marsh than in bog under the same incubation conditions. However, The CO_2 emission fluxes were lower in marsh than in bog, implying that soil enzyme activities can not independently be used as a parameter indicating CO_2 fluxes.