Sigler W V, Zeyer J
Soil Biology, Institute for Terrestrial Ecology, Swiss Federal Institute of Technology (ETH), 8952 Schlieren, Switzerland.
Microb Ecol. 2002 May;43(4):397-407. doi: 10.1007/s00248-001-0045-5. Epub 2002 Apr 15.
Forefields of two receding glaciers were sampled along either a 150 or 200 m long transect at identical spatial intervals for assessment of soil microbial activity and community diversity trends. The forefields belonged to the Dammaglacier (forefield area is 157 ha, 2000 m above sea level) and Rotfirnglacier (100 ha, 2200 m) and at the time of sampling were receding at an estimated rate of 8 and 10 m yr(-1) over the past 5 years, respectively. Direct counting of bacteria (DAPI staining), assessment of dehydrogenase activity (DH), and fluorescein diacetate hydrolysis activity (FDA) were performed to estimate bacteria number and soil microbial activity. Along the Dammaglacier forefield (from youngest to oldest soil), bacteria number (8.21 x 10(7) to 1.49 x 10(9) cells g(-1) soil), DH activity (0 to 61 mg TTC reduced g(-1) soil h(-1)), and FDA activity (0 to 100 mg fluorescein produced g-1 soil h-1) increased, suggesting the development of microbial populations increasing in number and activity. The Rotfirn forefield exhibited similar trends per gram of soil in bacteria number (1.13 x 10(8) to 5.93 x 10(9) cells), DH activity (0 to 36 mg TTC reduced), and FDA activity (2 to 70 mg fluorescein produced), but with more variability among samples than the Damma forefield samples. Molecular assessment of bacterial diversity included denaturing gradient gel electrophoresis (DGGE) and ribosomal intergenic spacer analysis (RISA) of soil DNA. DGGE and RISA revealed that the composition and succession of bacterial populations were different in both forefields. Comparison of Shannon diversity index values indicated that all populations sampled from the Damma forefield were significantly different (p < 0.05). Conversely, similar populations existed in the Rotfirn forefield succession. Overall, the results indicate that diverse bacterial assemblages increasing in number and activity characterize these glacier forefield soils with both forefield successions exhibiting differing modes of bacterial community establishment.
沿着两条退缩冰川的前缘区域，分别在150米或200米长的样带上按照相同的空间间隔进行采样，以评估土壤微生物活性和群落多样性趋势。这些前缘区域分别属于达姆冰川（前缘区域面积为157公顷，海拔2000米）和红峰冰川（100公顷，海拔2200米），在采样时，过去5年中它们分别以估计8米/年和10米/年的速度退缩。通过细菌直接计数（DAPI染色）、脱氢酶活性（DH）评估和荧光素二乙酸酯水解活性（FDA）评估来估计细菌数量和土壤微生物活性。沿着达姆冰川前缘区域（从最年轻的土壤到最古老的土壤），细菌数量（8.21×10⁷至1.49×10⁹个细胞/克土壤）、DH活性（0至61毫克三苯基氯化四氮唑还原/克土壤·小时）和FDA活性（0至100毫克荧光素产生/克土壤·小时）均增加，表明微生物种群数量和活性在增加。红峰冰川前缘区域每克土壤在细菌数量（1.13×10⁸至5.93×十⁹个细胞）。
