The effects of amoebal bacterivory on carbon and nitrogen dynamics depend on temperature and soil structure interactions
The effects of amoebal bacterivory on carbon and nitrogen dynamics depend on temperature and soil structure interactions
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DOI：
10.1016/j.soilbio.2015.11.021
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发表时间：
2016-03
影响因子：
9.7
通讯作者：
Geoffrey L. Zahn;Rota Wagai;S. Yonemura
中科院分区：
文献类型：
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作者：
Geoffrey L. Zahn;Rota Wagai;S. Yonemura
关于食菌原生生物在调节土壤碳（C）和氮（N）循环中的作用，包括原生生物与物理和化学因素相互作用以影响土壤分解者对温度升高的反应的方式，仍然存在一些基本问题。变形虫作为最丰富的土壤原生动物之一，尤其值得关注。使用简化的土壤群落的缩影，我们调查了净和互动的影响，阿米巴细菌，土壤团聚体结构，农业管理（耕作与免耕），温度对C和N动态在24天的孵化。呼吸温度的敏感性（Q10）是更易变的简化社区比自然社区，说明了使用低多样性系统来预测这样一个复杂的和紧急的属性的挑战。除了预期的积极影响，阿米巴捕食C和N矿化在所有治疗中，我们发现，这种效果的大小是显着影响聚集体结构和温度。在25 °C下观察到破碎聚集体中相对于完整聚集体具有统计学上更高（P < 0.01）的捕食诱导的C矿化，但在15 °C下未观察到，这意味着（i）在较高温度下，变形虫的捕食效率受到物理可达性的更多限制和/或（ii）具有不同营养生态位的捕食者物种的温度诱导的转变。我们的研究结果表明，更好地了解土壤食物网，团聚体结构和温度的相互作用时，预测土壤C和N动态变暖的情况下的重要性。
Fundamental questions remain about the role of bacterivorous protists in regulating soil carbon (C) and nitrogen (N) cycling, including the ways in which protists interact with physical and chemical factors to influence soil decomposer responses to increased temperature. Amoebae in particular deserve attention given their status as one of the most abundant soil protozoans. Using microcosms of simplified soil communities, we investigated the net and interactive effects of amoebal bacterivory, soil aggregate structure, agricultural management (till vs. no-till), and temperature on C and N dynamics during a 24 day-incubation. The respiration temperature sensitivity (Q10) was much more variable for the simplified communities than natural communities, illustrating the challenge in using low-diversity systems to predict such a complex and emergent property. In addition to the expected positive effect of amoebal predation on C and N mineralization in all treatments, we found that the magnitude of this effect was significantly influenced by aggregate structure and temperature. Statistically higher (P < 0.01) predation-induced C mineralization in crushed aggregates relative to intact aggregates was observed at 25 °C but not at 15 °C, implying that (i) amoebal predation efficiency is more limited by physical accessibility under higher temperature and/or (ii) a temperature-induced shift in predator species with differing trophic niches. Our results show the importance of better understanding the interactions of the soil food web, aggregate structure, and temperature when predicting soil C and N dynamics under warming scenarios.