Boyd T J, Montgomery M T, Steele J K, Pohlman J W, Reatherford S R, Spargo B J, Smith D C
Code 6114, U.S. Naval Research Laboratory, 4555 Overlook Ave, Washington, DC 20375, USA.
Microb Ecol. 2005 Feb;49(2):226-35. doi: 10.1007/s00248-004-0279-0. Epub 2005 Jun 17.
Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in terrestrial and aquatic environments and can represent a significant constituent of the carbon pool in coastal sediments. We report here the results of an 18-month seasonal study of PAH biodegradation and heterotrophic bacterial production and their controlling biogeochemical factors from 186 sediment samples taken in a tidally influenced freshwater estuary. For each sampling event, measurements were averaged from 25-45 stations covering approximately 250 km(2). There was a clear relationship between bacterial production and ambient temperature, but none between production and bottom water dissolved oxygen (DO) % saturation or PAH concentrations. In contrast with other studies, we found no effect of temperature on the biodegradation of naphthalene, phenanthrene, or fluoranthene. PAH mineralization correlated with bottom water DO saturation above 70% (r(2) > 0.99). These results suggest that the proportional utilization of PAH carbon to natural organic carbon is as much as three orders of magnitude higher during cooler months, when water temperatures are lower and DO % saturation is higher. Infusion of cooler, well-oxygenated water to the water column overlying contaminated sediments during the summer months may stimulate PAH metabolism preferentially over non-PAH organic matter.
多环芳烃（PAHs）是陆地和水生环境中的常见污染物，并且可能是沿海沉积物中碳库的重要组成部分。我们在此报告了一项为期18个月的季节性研究结果，该研究针对在一个受潮汐影响的淡水河口采集的186个沉积物样本，研究了多环芳烃的生物降解、异养细菌生产及其控制生物地球化学因素。对于每次采样事件，测量值是从覆盖约250 km²的25 - 45个站点的平均值。细菌生产与环境温度之间存在明显关系，但生产与底层水溶解氧（DO）饱和度百分比或多环芳烃浓度之间没有关系。与其他研究不同，我们发现温度对萘、菲或荧蒽的生物降解没有影响。多环芳烃矿化与底层水DO饱和度高于70%相关（r² > 0.99）。这些结果表明，在较凉爽的月份，当水温较低且DO饱和度较高时，多环芳烃碳相对于天然有机碳的比例利用率要高出多达三个数量级。在夏季，将较凉爽、含氧充足的水注入受污染沉积物上方的水柱中，可能会优先刺激多环芳烃的代谢而非非多环芳烃有机物的代谢。
