Section of Microbial Ecology, Department of Biology, Lund University, Ecology Building, 223 62, Lund, Sweden.
Glob Chang Biol. 2013 Dec;19(12):3872-84. doi: 10.1111/gcb.12338. Epub 2013 Oct 10.
We investigated how the legacy of warming and summer drought affected microbial communities in five different replicated long-term (>10 years) field experiments across Europe (EU-FP7 INCREASE infrastructure). To focus explicitly on legacy effects (i.e., indirect rather than direct effects of the environmental factors), we measured microbial variables under the same moisture and temperature in a brief screening, and following a pre-incubation at stable conditions. Specifically, we investigated the size and composition of the soil microbial community (PLFA) alongside measurements of bacterial (leucine incorporation) and fungal (acetate in ergosterol incorporation) growth rates, previously shown to be highly responsive to changes in environmental factors, and microbial respiration. We found no legacy effects on the microbial community size, composition, growth rates, or basal respiration rates at the effect sizes used in our experimental setup (0.6 °C, about 30% precipitation reduction). Our findings support previous reports from single short-term ecosystem studies thereby providing a clear evidence base to allow long-term, broad-scale generalizations to be made. The implication of our study is that warming and summer drought will not result in legacy effects on the microbial community and their processes within the effect sizes here studied. While legacy effects on microbial processes during perturbation cycles, such as drying-rewetting, and on tolerance to drought and warming remain to be studied, our results suggest that any effects on overall ecosystem processes will be rather limited. Thus, the legacies of warming and drought should not be prioritized factors to consider when modeling contemporary rates of biogeochemical processes in soil.
我们研究了变暖和夏季干旱的遗留影响如何影响欧洲五个不同复制的长期（> 10 年）野外实验中的微生物群落（欧盟 FP7 INCREASE 基础设施）。为了明确关注遗留效应（即环境因素的间接而非直接影响），我们在简短的筛选下在相同的水分和温度下测量了微生物变量，并在稳定条件下进行了预孵育。具体来说，我们研究了土壤微生物群落的大小和组成（PLFA），以及细菌（亮氨酸掺入）和真菌（麦角固醇中乙酸盐掺入）生长率的测量，这些生长率先前被证明对环境因素的变化高度敏感，以及微生物呼吸。我们在实验设置中使用的效应大小（0.6°C，约 30%的降水量减少）上没有发现微生物群落大小、组成、生长率或基础呼吸率的遗留效应。我们的研究结果支持了来自单个短期生态系统研究的先前报告，从而为允许进行长期、广泛的概括提供了明确的证据基础。我们研究的意义是，在研究中所研究的效应大小内，变暖和夏季干旱不会导致微生物群落及其过程的遗留效应。虽然在干扰循环（如干湿交替）期间以及对干旱和变暖的耐受性方面的微生物过程的遗留效应仍有待研究，但我们的结果表明，对整个生态系统过程的任何影响都将相当有限。因此，在对土壤中生物地球化学过程的当代速率进行建模时，变暖和干旱的遗留影响不应优先考虑因素。
