Soil dwelling microorganisms are key players in the terrestrial carbon cycle, driving both the degradation and stabilization of soil organic matter. Bacterial community structure and function vary with respect to land use; yet the ecological drivers of this variation remain poorly described and difficult to predict. We conducted a multi-substrate DNA-stable isotope probing experiment across cropland, old-field, and forest habitats to link carbon mineralization dynamics with the dynamics of bacterial growth and carbon assimilation. We tracked the movement of ¹³C derived from five distinct carbon sources as it was assimilated into bacterial DNA over time. We show that carbon mineralization, community composition, and carbon assimilation dynamics all differed with respect to land use. We also show that microbial community dynamics affect carbon assimilation dynamics and are associated with soil DNA content. Soil DNA yield is easy to measure and may be useful in predicting microbial community dynamics linked to soil carbon cycling. Soil dwelling microorganisms are key players in the terrestrial carbon cycle, driving both the degradation and stabilization of soil organic matter. Microbial communities vary with respect to land use, but we still have an incomplete understanding of how variation in community structure links to variation in community function. DNA stable isotope probing (DNA-SIP) is a high-resolution method that can identify specific microbial taxa that assimilate carbon in situ. We conducted a large-scale multi-substrate DNA-SIP experiment to explore differences in bacterial activity across land-use regimes. We show that microbial community dynamics vary with land use, that these dynamics are linked to soil carbon cycling, and that they are associated with easily measured soil properties.

中文翻译：

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细菌群落动力学解释了不同土地利用历史土壤中的碳矿化和同化

土壤微生物是陆地碳循环的关键参与者，推动土壤有机质的降解和稳定。细菌群落结构和功能因土地利用而异；然而，这种变化的生态驱动因素仍未得到很好的描述，也难以预测。我们在农田、旧田和森林栖息地进行了多底物 DNA 稳定同位素探测实验，以将碳矿化动态与细菌生长和碳同化动态联系起来。我们跟踪了^{13人的动向}C 源自五种不同的碳源，因为它随着时间的推移被同化到细菌 DNA 中。我们表明，碳矿化、群落组成和碳同化动力学都因土地利用而异。我们还表明，微生物群落动态影响碳同化动态，并与土壤 DNA 含量相关。土壤 DNA 产量易于测量，可用于预测与土壤碳循环相关的微生物群落动态。土壤微生物是陆地碳循环的关键参与者，推动土壤有机质的降解和稳定。微生物群落在土地利用方面各不相同，但我们对群落结构的变化如何与群落功能的变化相关联仍不完全了解。DNA 稳定同位素探测 (DNA-SIP) 是一种高分辨率方法，可以识别原位同化碳的特定微生物类群。我们进行了大规模多底物 DNA-SIP 实验，以探索不同土地利用制度下细菌活动的差异。我们表明微生物群落动态随土地利用而变化，这些动态与土壤碳循环有关，并且它们与易于测量的土壤特性有关。