Trophic level mediates soil microbial community composition and function
Trophic level mediates soil microbial community composition and function
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DOI：
10.1016/j.soilbio.2020.107756
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发表时间：
2020-04-01
影响因子：
9.7
通讯作者：
Strickland, Michael S.
中科院分区：
文献类型：
--
作者：
Lucas, Jane M.;McBride, Steven G.;Strickland, Michael S.
土壤微生物群落驱动生态系统过程，技术进步使人们对这些群落有了前所未有的了解。然而，微生物只是土壤群落的一个组成部分。了解土壤微生物如何对土壤食物网营养水平的变化做出反应，特别是结合不稳定碳资源的输入，对于全面了解地下动态至关重要。在这里，我们操纵土壤群落的营养水平，创造了一种微生物处理，一种微生物食性处理和两种捕食者处理，以测试消耗和非消耗效应。然后，我们将这些群落暴露于模拟根际或散装土壤的葡萄糖添加物中。我们发现，添加和不添加葡萄糖的营养水平会导致微生物群落组成和功能的变化。具体来说，我们观察到，与只含有微生物的处理相比，增加营养水平的存在导致了不同的细菌群落，而与微生物处理相比，捕食者的存在导致了最明显的变化。毫不奇怪，与散装土壤相比，根际土壤呼吸作用更大，微生物处理的根际土壤呼吸作用分别比其他处理的根际土壤呼吸作用更大和更小。然而，不同处理之间呼吸的相似性是由不同的潜在过程驱动的，其中捕食者的存在导致微生物生物量和微生物效率的增加。事实上，与可利用的不稳定碳相比，营养水平对微生物效率的影响更大。这表明，在试图了解土壤微生物群落对生态系统过程的影响时，应考虑土壤群落的营养水平。
Soil microbial communities drive ecosystem processes, and technological advances have led to an unprecedented understanding of these communities. Yet microbes are only one constituent of soil communities. Understanding how soil microbes will respond to changes in the trophic levels of soil food webs, particularly in combination with inputs of labile carbon resources, is vital for a complete picture of belowground dynamics. Here we manipulate the trophic levels of soil communities, creating a microbe treatment, a microbivore treatment, and two predator treatments that test between consumptive and non-consumptive effects. We then exposed these communities to glucose additions that simulate either the rhizosphere or bulk soil. We found that trophic levels, with and without glucose addition, lead to shifts in microbial community composition and function. Specifically, we observed that the presence of increasing trophic levels led to distinct bacterial communities compared to treatments containing only microbes, and the presence of the predator led to the most distinct shifts compared to the microbe treatment. Not surprisingly, soil respiration was greater in the rhizosphere compared to the bulk soil with the microbe treatment exhibiting greater and lesser respiration compared to the other treatments in the rhizosphere versus the bulk soil, respectively. However, the similarity in respiration between treatments was driven by different underlying processes where the presence of the predator leads to increased microbial biomass and microbial efficiency. In fact, trophic levels, compared to the availability of labile carbon, had a greater influence on microbial efficiency. This suggests that trophic levels of soil communities should be considered when attempting to understand the effect of soil microbial communities on ecosystem processes.