Viruses are abundant and diverse members of soil communities, but their influences on soil biogeochemical cycling are poorly understood. To assess the potential for viruses to influence soil carbon (C) cycling in varying environmental contexts, we sampled soils from four contrasting ecosystem types across the continental United States: conifer forest, broadleaf deciduous forest, tallgrass prairie, and agricultural cropland. We then experimentally increased virus abundance in the soils by inoculating microcosms with virus concentrates isolated from the same original soils and incubated the soils for 14 days. The virus-treated conifer forest and prairie soils respired significantly less C (14 μg and 10 μg less C per gram of soil, respectively) over the course of the 14-day incubation compared with control soils, though the effects were proportionally small in magnitude (3% and 6% reductions in cumulative respiration, respectively). Following the initial 14-day incubation, we conducted aC-glucose tracer incubation. In contrast to the initial incubation, after glucose addition we observed effects on respiration only in the agricultural soil, where respiration of soil organic matter-derived C nearly doubled in the virus-treated soils compared with control soils. We also observed overall reduced incorporation of C into microbial biomass (, lower growth yield) and lower carbon use efficiency on average in all virus-treated soils. These results demonstrate that viruses can influence overall microbial metabolism but with different aggregate effects on soil C balance across soil types depending on soil physicochemical properties. Overall, our study demonstrates that viral influences on soil microorganisms can manifest in altered fates of soil C, with either increased or decreased respiratory C loss depending on ecosystem type.

中文翻译：

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实验性升高的病毒丰度对不同生态系统类型土壤碳循环的影响


病毒是土壤群落中丰富多样的成员，但它们对土壤生物地球化学循环的影响却知之甚少。为了评估病毒在不同环境背景下影响土壤碳 (C) 循环的潜力，我们对美国大陆四种不同生态系统类型的土壤进行了采样：针叶林、阔叶落叶林、高草草原和农田。然后，我们通过用从相同的原始土壤中分离出的病毒浓缩物接种微观世界并将土壤培养 14 天来实验性地增加了土壤中的病毒丰度。在 14 天的培养过程中，与对照土壤相比，经过病毒处理的针叶林和草原土壤呼吸的碳显着减少（每克土壤分别减少 14 微克和 10 微克碳），但影响程度较小（累积呼吸分别减少 3% 和 6%）。在最初的 14 天孵化后，我们进行了 aC-葡萄糖示踪孵化。与初始培养相反，添加葡萄糖后，我们仅在农业土壤中观察到对呼吸的影响，其中与对照土壤相比，经过病毒处理的土壤中源自土壤有机质的碳的呼吸几乎增加了一倍。我们还观察到，在所有经过病毒处理的土壤中，微生物生物量中碳的掺入量总体减少（生长产量降低），碳利用效率平均降低。这些结果表明，病毒可以影响整体微生物代谢，但根据土壤理化性质，对不同类型土壤的土壤碳平衡具有不同的总体影响。 总体而言，我们的研究表明，病毒对土壤微生物的影响可以表现为土壤碳命运的改变，根据生态系统类型，呼吸性碳损失的增加或减少。