Taylor Anne E, Giguere Andrew T, Zoebelein Conor M, Myrold David D, Bottomley Peter J
Department of Crop and Soil Science, Oregon State University, Corvallis, OR, USA.
Department of Environmental Engineering, Oregon State University, Corvallis, OR, USA.
ISME J. 2017 Apr;11(4):896-908. doi: 10.1038/ismej.2016.179. Epub 2016 Dec 20.
Soil nitrification potential (NP) activities of ammonia-oxidizing archaea and bacteria (AOA and AOB, respectively) were evaluated across a temperature gradient (4-42 °C) imposed upon eight soils from four different sites in Oregon and modeled with both the macromolecular rate theory and the square root growth models to quantify the thermodynamic responses. There were significant differences in response by the dominant AOA and AOB contributing to the NPs. The optimal temperatures (T) for AOA- and AOB-supported NPs were significantly different (P<0.001), with AOA having T>12 °C greater than AOB. The change in heat capacity associated with the temperature dependence of nitrification (ΔC) was correlated with T across the eight soils, and the ΔC of AOB activity was significantly more negative than that of AOA activity (P<0.01). Model results predicted, and confirmatory experiments showed, a significantly lower minimum temperature (T) and different, albeit very similar, maximum temperature (T) values for AOB than for AOA activity. The results also suggested that there may be different forms of AOA AMO that are active over different temperature ranges with different T, but no evidence of multiple T values within the AOB. Fundamental differences in temperature-influenced properties of nitrification driven by AOA and AOB provides support for the idea that the biochemical processes associated with NH oxidation in AOA and AOB differ thermodynamically from each other, and that also might account for the difficulties encountered in attempting to model the response of nitrification to temperature change in soil environments.
在俄勒冈州四个不同地点采集的八种土壤上，施加了一个温度梯度（4-42°C），评估了氨氧化古菌和细菌（分别为AOA和AOB）的土壤硝化潜力（NP）活性，并用大分子速率理论和平方根生长模型进行建模，以量化热力学响应。对NP有贡献的主要AOA和AOB的响应存在显著差异。AOA和AOB支持的NP的最佳温度（T）显著不同（P<0.001），AOA的T>12°C大于AOB。与硝化作用温度依赖性相关的热容变化（ΔC）与八种土壤的T相关，AOB活性的ΔC显著比AOA活性的更负（P<0.01）。模型结果预测并经验证实验表明，AOB的最低温度（T）显著低于AOA活性，最高温度（T）值不同，尽管非常相似。结果还表明，可能存在不同形式的AOA AMO，它们在不同温度范围内具有不同的T值时具有活性，但在AOB内没有多个T值的证据。由AOA和AOB驱动的硝化作用受温度影响的特性存在根本差异，这支持了以下观点：与AOA和AOB中NH氧化相关的生化过程在热力学上彼此不同，这也可能解释了在尝试模拟土壤环境中硝化作用对温度变化的响应时遇到的困难。
