Historical precipitation regimes structure the growth of soil microorganisms in three California annual grasslands

摘要: Earth system models project altered precipitation regimes across much of the globe. Soil microorganisms in Mediterranean climates must withstand both direct physiological stress during prolonged periods of low soil moisture and be able to compete for resources when seasonal rains return and plant growth resumes5. However, we do not have a mechanistic understanding of how altered soil moisture regimes affect microbial population dynamics and in turn how this will affect soil carbon (C) persistence. We used quantitative stable isotope probing (qSIP) to compare total and growing soil microbial communities across three California annual grassland ecosystems with Mediterranean climates that span a rainfall gradient and have developed from similar parent material. Sampling was conducted during the wet season, when environmental conditions were most similar across the sites. We assessed multiple …