Langworthy D E, Stapleton R D, Sayler G S, Findlay R H
Department of Microbiology, Miami University, Oxford, OH 45056, USA.
Microb Ecol. 2002 Mar;43(2):189-98. doi: 10.1007/s00248-001-1040-6. Epub 2002 Jan 2.
Polycyclic aromatic hydrocarbons (PAH) are widespread environmental contaminants that can, under proper conditions, be degraded by microorganisms. The responses of a riverine sedimentary microbial community to PAH contamination were examined using an integrated biochemical assay that yielded data on PAH concentration, total microbial biomass, and microbial community structure and were interpreted using perturbation theory and the subsidy-stress gradient. Microbial mineralization of naphthalene, anthracene, fluorene, and phenanthrene was observed 24 h after their addition to all sediments sampled and ranged from 0.9 to 16.3% in ambient sediments and from 14.8 to 35.8% in contaminated sediments. Total microbial biomass, determined by phospholipid phosphate, increased in response to intermediate PAH concentration and decreased at sites with the highest PAH concentration (p < 0.05) during seven out of nine (78%) seasonal sampling periods. The two sampling periods that were not statistically different followed periods of high water and cold temperatures. Phospholipid fatty acid analysis of microbial community structure analysis indicated that increases in the relative abundance of gram-negative aerobes and heterotrophic eukaryotes were responsible, in part, for these observed increases in total microbial biomass. These findings (increased degradation rates, increased biomass at intermediate PAH concentrations, and altered community structure) indicate that a component of the microbial community responded to PAH as a usable input and are consistent with the predictions of perturbation theory and a subsidy-stress gradient.
多环芳烃（PAH）是广泛存在的环境污染物，在适当条件下可被微生物降解。利用一种综合生化分析方法研究了河流沉积微生物群落对PAH污染的响应，该方法可得出PAH浓度、总微生物生物量以及微生物群落结构的数据，并运用扰动理论和补贴-压力梯度进行解读。在向所有采集的沉积物中添加萘、蒽、芴和菲24小时后，观察到了微生物矿化现象，在未受污染的沉积物中，矿化率为0.9%至16.3%，在受污染的沉积物中为14.8%至35.8%。在九个季节性采样期的七个（78%）中，通过磷脂磷酸盐测定的总微生物生物量，对中等PAH浓度作出响应而增加，在PAH浓度最高的位点则下降（p < 0.05）。未出现统计学差异的两个采样期是在高水位和低温期之后。微生物群落结构分析的磷脂脂肪酸分析表明，革兰氏阴性需氧菌和异养真核生物相对丰度的增加，部分导致了观察到的总微生物生物量的增加。这些发现（降解率提高、中等PAH浓度下生物量增加以及群落结构改变）表明，微生物群落的一个组成部分将PAH作为可用输入作出了响应，这与扰动理论和补贴-压力梯度的预测一致。
