贵阳市湖泊沉积物中铁还原菌的季节分布

Seasonal distribution of dissimilatory iron-reducing bacteria in reservoir sediments of Guiyang City

采用滚管计数法检测了贵阳市红枫湖、百花湖、阿哈湖沉积物不同季节铁还原菌（DIRB）含量，并分析了其pH及有机质等理化参数，检测了其沉积物孔隙水中铁、硫酸根含量。阿哈湖、百花湖和红枫湖沉积物中DIRB含量分别为1．09×10 4～8．83×10 5、1．05×10 4～3．43×10 5和4．80×10 3-4．47×10 5cells·g-1。暖季（6和9月）沉积物DIRB含量高于冬季（2月）l一2个数量级，且表层沉积物DIRB含量与界面水溶解氧含量呈显著相关（P〈0．05），表明沉积物DIRB含量受溶解氧和温度影响明显。由于受到沉积物中O2、SO4 2-扣等其他微生物可利用电子受体的控制，沉积物剖面上DIRB活动区域随着冬夏季节交替有向沉积物上部迁移的趋势。虽然阿哈湖长期受酸性煤矿废水污染，但各湖泊丰富的有机质（60～140g·kg-1）及适宜的pH（6．2～7．1）为铁还原菌的生长提供了适宜的生长环境，使得水库之间沉积物铁还原菌在数量级上差异不大，但阿哈湖沉积物中铁还原菌生长峰值明显高于红枫湖、百花湖。

Using the rolling tube technique, biomass of dissimilatory iron-reducing bacteria （DIRB） was detected in sediments of three reservoirs in Guiyang in different seasons, and at the same time, physical and chemical parameters, such as the iron and sulfate contents of pore water, pH, organic matter contents in the sediments were measured. The biomass of DIRB in the sediments of Aha Reservoir, Baihua Reservoir and Hongfeng Reservoir ranged from 1. 09× 10 4 to 8. 829×10 5 from 1.05×10 4 to 3. 425×10 5 and from 4.8×10 3 to 4.467×10 5 cells · g-1 respec- tively. The biomass of DIRB in the warm season （June and September） was 1-2 orders of magnitude higher than that in the cold season （February） , and the dissolved oxygen （DO） in the water-sediment intersurface was correlated to DIRB biomass in the surface sediment, suggesting that DO and temperature had a great effect on DIRB biomass. In addition, the active areas of DIRB migrated to the top of the upper sediment with the alternation of the cold to warm season, as other electron acceptors such as 02 , SO4 2- in the sediment controlled the profile distribution of DIRB. Aha Reservoir had been polluted by acid mine drainage, but the biomass of D1RB had no difference in orders of magnitude among the three reservoirs, probably because the high sediment organic matter contents （60-140 g · kg-1 ） and optimum pH （6.2-7.1） in these reservoirs contributed to the growth of DIRB, but the peaks of the sediment DIRB biomass in Aha Reservoir were higher than in the other two reservoirs.