Lipson David A, Blair Michelle, Barron-Gafford Greg, Grieve Kathrine, Murthy Ramesh
Department of Biology, San Diego State University, San Diego, CA 92182-4614, USA.
Microb Ecol. 2006 Apr;51(3):302-14. doi: 10.1007/s00248-006-9032-1. Epub 2006 Apr 6.
There is little current understanding of the relationship between soil microbial community composition and soil processes rates, nor of the effect climate change and elevated CO(2) will have on microbial communities and their functioning. Using the eastern cottonwood (Populus deltoides) plantation at the Biosphere 2 Laboratory, we studied the relationships between microbial community structure and process rates, and the effects of elevated atmospheric CO(2) on microbial biomass, activity, and community structure. Soils were sampled from three treatments (400, 800, and 1200 ppm CO(2)), a variety of microbial biomass and activity parameters were measured, and the bacterial community was described by 16S rRNA libraries. Glucose substrate-induced respiration (SIR) was significantly higher in the 1200 ppm CO(2) treatment. There were also a variety of complex, nonlinear responses to elevated CO(2). There was no consistent effect of elevated CO(2) on bacterial diversity; however, there was extensive variation in microbial community structure within the plantation. The southern ends of the 800 and 1200 ppm CO(2) bays were dominated by beta-Proteobacteria, and had higher fungal biomass, whereas the other areas contained more alpha-Proteobacteria and Acidobacteria. A number of soil process rates, including salicylate, glutamate, and glycine substrate-induced respiration and proteolysis, were significantly related to the relative abundance of the three most frequent bacterial taxa, and to fungal biomass. Overall, variation in microbial activity was better explained by microbial community composition than by CO(2) treatment. However, the altered diversity and activity in the southern bays of the two high CO(2) treatments could indicate an interaction between CO(2) and light.
目前对于土壤微生物群落组成与土壤过程速率之间的关系，以及气候变化和二氧化碳浓度升高对微生物群落及其功能的影响了解甚少。我们利用生物圈2实验室的东部杨树林（Populus deltoides）种植园，研究了微生物群落结构与过程速率之间的关系，以及大气二氧化碳浓度升高对微生物生物量、活性和群落结构的影响。从三种处理（400、800和1200 ppm二氧化碳）中采集土壤，测量了各种微生物生物量和活性参数，并通过16S rRNA文库描述了细菌群落。在1200 ppm二氧化碳处理中，葡萄糖底物诱导呼吸（SIR）显著更高。对于二氧化碳浓度升高也存在各种复杂的非线性响应。二氧化碳浓度升高对细菌多样性没有一致的影响；然而，种植园内微生物群落结构存在广泛差异。800和1200 ppm二氧化碳区域的南端以β-变形菌为主，真菌生物量较高，而其他区域含有更多的α-变形菌和酸杆菌。一些土壤过程速率，包括水杨酸盐、谷氨酸和甘氨酸底物诱导呼吸以及蛋白水解，与三种最常见细菌类群的相对丰度以及真菌生物量显著相关。总体而言，微生物群落组成比二氧化碳处理能更好地解释微生物活性的变化。然而，两种高二氧化碳处理区域南端多样性和活性的改变可能表明二氧化碳与光照之间存在相互作用。
