Pacific Northwest Laboratory, Richland, Washington 99352, and Department of Biological Science, Florida State University, Tallahassee, Florida 32306.
Appl Environ Microbiol. 1991 Feb;57(2):402-11. doi: 10.1128/aem.57.2.402-411.1991.
A series of 23 intact core segments was obtained from two distinct deep subsurface geological formations, the Middendorf and the Cape Fear formations, underlying the southeastern coastal plain of South Carolina. The Middendorf formation in this region consists of permeable, saturated, sandy sediments; the Cape Fear formation consists mainly of less permeable sediments. The core segments were separated by vertical distances ranging from several centimeters to 48 m. Aerobic chemoheterotrophic bacteria were enumerated on a dilute medium, and populations ranged from 3.1 to 6.4 log CFU g of sediment in the Middendorf cores and from below detection to 4.3 log CFU g in the Cape Fear cores. A total of 198 morphologically distinct colony types were isolated, purified, and subjected to 108 different physiological measurements. The isolates from the two formations were distinct (i.e., they produced substantially different response patterns to the various physiological measurements), as were those in different core samples from the same formation. Cluster analysis revealed 21 different biotypes based on similarities of 75% or higher in response patterns to 21 physiological assays. One biotype contained 57 (29%) of the subsurface isolates, 10 biotypes contained 5 or more isolates, and the remainder had 4 or fewer. The organic compounds that were most commonly metabolized by the subsurface bacteria included Tween 40 (85%) and beta-hydroxybutyric acid (60%). Organic acids, in general, were also commonly metabolized by the subsurface bacteria. Isolates from the Cape Fear core segments were capable of metabolizing a higher percentage of the substrates than were bacteria isolated from the Middendorf formation. Although the heterogeneous distributions of bacteria in deep subsurface sediments may make it difficult to use aquifer microcosms to predict in situ biotransformation rates, the diversity of the physiological properties of these organisms offers promise for in situ remediation of contaminants.
从南卡罗来纳州东南沿海平原下方两个不同的深部地下地质构造——米登多夫和海角恐惧地层中，获得了一系列 23 个完整的核心段。该地区的米登多夫地层由可渗透、饱和的砂质沉积物组成；海角恐惧地层主要由渗透性较差的沉积物组成。核心段之间的垂直距离从几厘米到 48 米不等。在稀培养基上对好氧化感异养菌进行计数，米登多夫核心中的种群数量范围为 3.1 至 6.4 对数 CFU/g 沉积物，而在海角恐惧核心中的种群数量则低于检测下限至 4.3 对数 CFU/g。总共分离出 198 种形态不同的菌落类型，并对其进行了 108 种不同的生理测量。来自两个地层的分离物是不同的（即，它们对各种生理测量的反应模式有很大的不同），来自同一地层的不同核心样本中的分离物也是不同的。聚类分析根据对 21 种生理测定的反应模式相似性为 75%或更高，揭示了 21 种不同的生物型。一种生物型包含 57 个（29%）地下分离物，10 种生物型包含 5 个或更多分离物，其余的则包含 4 个或更少的分离物。地下细菌最常代谢的有机化合物包括吐温 40（85%）和β-羟基丁酸（60%）。一般来说，有机酸也被地下细菌广泛代谢。来自海角恐惧核心段的分离物能够代谢更高比例的底物，比从米登多夫地层中分离的细菌。尽管深部地下沉积物中的细菌分布不均可能使利用含水层微宇宙预测原位生物转化率变得困难，但这些生物的生理特性的多样性为原位修复污染物提供了希望。
