Department of Microbiology, Stocking Hall, Cornell University, 14853, Ithaca, New York, USA.
Microb Ecol. 1988 Jul;16(1):85-97. doi: 10.1007/BF02097407.
Distribution and activity of microorganisms in surface soil and subsurface sediments were studied in depth profiles of six different microbial biomass and activity indicators (total direct counts, number of cells capable of electron transport system activity, viable cell plate counts, most Probable numbers of protozoa, and 4-hydroxybenzoate-degrading microorganisms, and ATP content). The profiles showed the same general trends on two different dates (January and June 1985). Seasonal variations were noted, but they were not extreme. Biomass and activity values declined sharply with depth in the unsaturated zone, reaching minima in a clay confining layer in the interface zone between 3 and 4 m. Contiguous 10-cm samples from the interface zone showed significant textural and microbiological variability. Higher and more stable biomass and activity values were detected in the saturated zone, the highest being a very permeable gravelly loamy sand layer at approximately 7.5 m. In this layer, viable counts were nearly equal to total counts and they approached the viable counts in surface soil. Surface-type protozoa and cyanobacteria also were detected in this layer, suggesting that it was connected hydrologically to a nearby river. Lowest values were detected in an underlying bedrock clay layer at 8 m, which, despite its impermeability and low viable counts, did contain measurable total counts, 4-hydroxybenzoate-degrading microorganisms, and ATP. Correlations were noted between sediment texture and microbial activity (i.e., sandy texture=high activity, clayey texture=low activity), but other hydrogeological and geochemical factors probably also influenced microbial distribution and activity in the profile.
在六个不同的微生物生物量和活性指标（总直接计数、具有电子传递系统活性的细胞数、活菌平板计数、原生动物最可能数、4-羟基苯甲酸降解微生物和 ATP 含量）的深度剖面中，研究了表层土壤和地下沉积物中微生物的分布和活性。这些剖面在两个不同的日期（1985 年 1 月和 6 月）表现出相同的总体趋势。注意到季节性变化，但并不极端。生物量和活性值在非饱和带中随深度急剧下降，在 3 至 4 米之间的界面区的粘土层中达到最小值。来自界面区的相邻 10-cm 样本显示出显著的质地和微生物变异性。在饱和带中检测到更高和更稳定的生物量和活性值，最高值是在大约 7.5 米处的非常透水的砾质壤土砂层。在该层中，活菌计数几乎等于总计数，并且接近表层土壤中的活菌计数。在该层中还检测到表面型原生动物和蓝细菌，表明它在水文学上与附近的河流相连。在 8 米处的下部基岩粘土层中检测到最低值，尽管其不透水性和活菌计数低，但仍含有可测量的总计数、4-羟基苯甲酸降解微生物和 ATP。注意到沉积物质地和微生物活性之间的相关性（即，砂质质地=高活性，粘质质地=低活性），但其他水文地质和地球化学因素也可能影响剖面中微生物的分布和活性。
