Microbial growth within the water-saturated subsurface environment was investigated by exposing sandy sediments to groundwater for 12 weeks at a depth of 10 or 20 m in a stainless-steel groundwater well. Washing and heating the sediment to 600 degrees C (removal of organic carbon) prior to the exposure did not prevent the natural microbial community from colonizing the sterilized sediment samples. Total cell counts of more than 10(7) or 10(8) per g of dried sediment were obtained. Viable cell counts of 10(5) cells per g on oligotrophic media indicated the presence, within the exposed sediment, of a highly active and multiplying biota. Microscopic analysis of enrichments inoculated with exposed sediment samples revealed a total of 45 different morphotypes, approximately 42% of the microbial community observed in previous studies of this site. The interstitial water running off of the retrieved sediment contained only 17 morphotypes and had up to 6 x 10(5) viable cells per ml.
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机译：通过在不锈钢地下水井中的10或20 m深度将砂质沉积物暴露于地下水中12周，研究了水饱和的地下环境中的微生物生长。在暴露之前将沉淀物洗涤并加热到600摄氏度（除去有机碳）并不能防止天然微生物群落定殖在无菌沉淀物中。每克干燥沉淀物获得的总细胞数超过10（7）或10（8）。在贫营养培养基上每克10（5）个细胞的活细胞计数表明，在暴露的沉积物中存在高度活跃且繁殖中的生物群。接种暴露的沉积物样品的富集的显微镜分析显示，共有45种不同的形态型，约占该站点先前研究中微生物群落的42％。从回收的沉积物中流出的间隙水仅含有17种形态型，每毫升最多有6 x 10（5）个活细胞。
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