Oak Ridge National Laboratory, Environmental Sciences Division, 37831-6036, Oak Ridge, Tennessee, USA.
Microb Ecol. 1994 Jan;28(3):351-64. doi: 10.1007/BF00662028.
The abundance and metabolic capacities of microorganisms residing in 49 sediment samples from 4 boreholes in Atlantic Coastal Plain sediments were examined. Radiolabeled time-course experiments assessing in situ mirobial capacities were initiated within 30 min of core recovery. Acetate (1-(14)C- and(3)H-) incorporation into lipids, microbial colony forming units, and nutrient limitations were examined in aliquots of subsurface sediments. Water-saturated sands exhibited activity and numbers of viable microorganisms that were orders of magnitude greater than those of the low permeability dense clays. Increased radioisotope utilization rates were observed after 6-24-h incubation times when sediments were amended with additional water and/or nutrients. Supplements of water, phosphate, nitrate, sulfate, glucose, or minerals resulted in the stimulation of microbial activities, as evidenced by the rate of acetate incorporation into microbial lipids. Additions of water or phosphate resulted in the greatest stimulation of microbial activities. Regardless of depth, sediments that contained >20% clay particles exhibited lower activities and biomass densities, and greater stimulation with abundant water supplementation than did sediments containing >66% sands and hydraulic conductivities > 200 μm sec.(-1).
对取自大西洋沿海平原沉积物 4 个钻孔的 49 个沉积物样本中的微生物的丰度和代谢能力进行了研究。在岩芯回收后 30 分钟内启动了放射性标记时程实验，以评估原位微生物的能力。在亚表层沉积物的等分试样中，研究了乙酸（1-（14）C-和（3）H-）掺入脂质、微生物菌落形成单位和营养限制的情况。水饱和砂的活性和可培养微生物数量比低渗透率致密粘土高几个数量级。在 6-24 小时的孵育时间后，当用额外的水和/或养分处理沉积物时，观察到放射性同位素利用率增加。水、磷酸盐、硝酸盐、硫酸盐、葡萄糖或矿物质的添加导致微生物活性的刺激，这可以通过乙酸掺入微生物脂质的速率来证明。水或磷酸盐的添加导致微生物活性的最大刺激。无论深度如何，含有>20%粘土颗粒的沉积物的活性和生物量密度较低，并且与含有>66%砂和水力传导率>200 μm sec.（-1）的沉积物相比，需要大量水补充才能得到更大的刺激。
