Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA.
ISME J. 2011 Oct;5(10):1692-700. doi: 10.1038/ismej.2011.32. Epub 2011 Mar 31.
The soil microbiome is responsible for mediating key ecological processes; however, little is known about its sensitivity to climate change. Observed increases in global temperatures and alteration to rainfall patterns, due to anthropogenic release of greenhouse gases, will likely have a strong influence on soil microbial communities and ultimately the ecosystem services they provide. Therefore, it is vital to understand how soil microbial communities will respond to future climate change scenarios. To this end, we surveyed the abundance, diversity and structure of microbial communities over a 2-year period from a long-term in situ warming experiment that experienced a moderate natural drought. We found the warming treatment and soil water budgets strongly influence bacterial population size and diversity. In normal precipitation years, the warming treatment significantly increased microbial population size 40-150% but decreased diversity and significantly changed the composition of the community when compared with the unwarmed controls. However during drought conditions, the warming treatment significantly reduced soil moisture thereby creating unfavorable growth conditions that led to a 50-80% reduction in the microbial population size when compared with the control. Warmed plots also saw an increase in species richness, diversity and evenness; however, community composition was unaffected suggesting that few phylotypes may be active under these stressful conditions. Our results indicate that under warmed conditions, ecosystem water budget regulates the abundance and diversity of microbial populations and that rainfall timing is critical at the onset of drought for sustaining microbial populations.
土壤微生物组负责调节关键的生态过程；然而，人们对其对气候变化的敏感性知之甚少。由于人为释放温室气体导致全球气温升高和降雨模式改变，很可能对土壤微生物群落产生强烈影响，并最终影响它们提供的生态系统服务。因此，了解土壤微生物群落将如何应对未来的气候变化情景至关重要。为此，我们在经历中度自然干旱的长期原位增温实验中，对微生物群落的丰度、多样性和结构进行了为期两年的调查。我们发现，增温处理和土壤水分收支强烈影响细菌种群规模和多样性。在正常降水年份，与未增温对照相比，增温处理显著增加了微生物种群规模 40-150%，但降低了多样性，并显著改变了群落组成。然而，在干旱条件下，增温处理显著降低了土壤水分，从而创造了不利于生长的条件，与对照相比，微生物种群规模减少了 50-80%。增温处理还增加了物种丰富度、多样性和均匀度；然而，群落组成不受影响，这表明在这些胁迫条件下，少数分类群可能是活跃的。我们的结果表明，在增温条件下，生态系统水分预算调节微生物种群的丰度和多样性，降雨时间在干旱开始时对维持微生物种群至关重要。
