Fierer Noah, Jackson Robert B
Department of Biology and Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, USA.
Proc Natl Acad Sci U S A. 2006 Jan 17;103(3):626-31. doi: 10.1073/pnas.0507535103. Epub 2006 Jan 9.
For centuries, biologists have studied patterns of plant and animal diversity at continental scales. Until recently, similar studies were impossible for microorganisms, arguably the most diverse and abundant group of organisms on Earth. Here, we present a continental-scale description of soil bacterial communities and the environmental factors influencing their biodiversity. We collected 98 soil samples from across North and South America and used a ribosomal DNA-fingerprinting method to compare bacterial community composition and diversity quantitatively across sites. Bacterial diversity was unrelated to site temperature, latitude, and other variables that typically predict plant and animal diversity, and community composition was largely independent of geographic distance. The diversity and richness of soil bacterial communities differed by ecosystem type, and these differences could largely be explained by soil pH (r(2) = 0.70 and r(2) = 0.58, respectively; P < 0.0001 in both cases). Bacterial diversity was highest in neutral soils and lower in acidic soils, with soils from the Peruvian Amazon the most acidic and least diverse in our study. Our results suggest that microbial biogeography is controlled primarily by edaphic variables and differs fundamentally from the biogeography of "macro" organisms.
几个世纪以来，生物学家一直在大陆尺度上研究动植物的多样性模式。直到最近，对于微生物（可以说是地球上最多样化、数量最丰富的生物群体）来说，类似的研究仍无法开展。在此，我们展示了一份关于土壤细菌群落以及影响其生物多样性的环境因素的大陆尺度描述。我们从南北美洲各地收集了98份土壤样本，并使用核糖体DNA指纹图谱法对各采样点的细菌群落组成和多样性进行定量比较。细菌多样性与采样点温度、纬度以及其他通常用于预测动植物多样性的变量无关，并且群落组成在很大程度上与地理距离无关。土壤细菌群落的多样性和丰富度因生态系统类型而异，并且这些差异在很大程度上可以用土壤pH值来解释（分别为r(2) = 0.70和r(2) = 0.58；两种情况下P均< 0.0001）。细菌多样性在中性土壤中最高，在酸性土壤中较低，在我们的研究中，秘鲁亚马逊地区的土壤酸性最强且多样性最低。我们的研究结果表明，微生物生物地理学主要受土壤变量控制，并且与“宏观”生物的生物地理学有着根本区别。
