【摘要】 为研究多环芳烃(菲)添加对珠江口河流湿地土壤氮矿化的影响,选取珠江三角洲番禺区的农村河流和城市河流湿地,采用鲜土对两种湿地土壤添加3种浓度的菲(0、15、100 mg·kg-1)进行为期42 d的室内培养实验,分析了两类湿地土壤氮矿化速率以及影响氮矿化过程的脲酶活性及氨氧化古菌(AOA)与氨氧化细菌(AOB)的比例变化。结果表明:土壤氮矿化速率变化范围为-4.885～5.877 mg·kg-1·d-1,氨化速率变化范围为-3.823～4.677 mg·kg-1·d-1,硝化速率变化范围为-4.990～5.369 mg·kg-1·d-1。所有处理中脲酶活性均呈下降趋势,下降比例在26.1%～83.4%的范围内。多环芳烃添加处理组下降比例显著小于无添加对照组(P<0.05),而农村河流湿地中的高浓度处理组除外(P>0.05)。农村河流湿地中,无添加和高浓度处理下培养后的AOB在氨氧化过程中的占比比培养前减少25.85%和7.31%,低浓度添加则增加36.37%。而菲添加对城市河流湿地AOA和AOB两者比例变化的影响较小。研究表明,除高浓度多环芳烃添加利于城市河流湿地土壤氮矿化外,其他添加实验均显示多环芳烃不利于土壤氮矿化。与对照组相比,多环芳烃的添加对土壤脲酶活性有促进作用(农村河流湿地高浓度处理除外)。在农村河流湿地土壤中,AOB对多环芳烃适应性比AOA更强,低浓度适应性最高,而多环芳烃对城市河流湿地土壤氨氧化微生物群落结构基本无影响。更多还原

【Abstract】 Soil samples were collected from rural and urban river wetlands in the Panyu district of the Pearl River Estuary to investigate the effect of polycyclic aromatic hydrocarbon(phenanthrene)addition on soil nitrogen mineralization processes in both types of wetlands. To analyze the changes in nitrogen mineralization rates, urease activities and the ratios of ammonia-oxidizing archaea(AOA)to ammonia-oxidizing bacteria(AOB)in the process of nitrogen mineralization in both wetland soils were analyzed under three phenanthrene-addition treatments(0, 15 mg·kg-1, and 100 mg·kg-1)throughout a 42-day laboratory incubation experiment. Soil nitrogen mineralization rates under all treatments ranged from-4.885 mg·kg-1·d-1 to 5.877 mg·kg-1·d-1.The rate of ammonization varied from-3.823 mg·kg-1·d-1 to 4.677 mg·kg-1·d-1, and the rate of nitrification ranged from-4.990 mg·kg-1·d-1 to 5.369 mg·kg-1·d-1. Urease activities declined with increasing incubation time under all three treatments, with the decreasing percentages ranging between 26.1% and 83.4%. The decrease in percentages under phenanthrene addition was significantly lower than those under control conditions(P<0.05), except for rural river wetland soils under high levels of phenanthrene addition(P>0.05). In rural river wetland soils, the proportion of AOB of ammoxidation microbials under no phenanthrene addition and high levels of phenanthrene addition decreased by 25.85% and 7.31%, respectively, while the proportion increased by 36.37% under low levels of phenanthrene addition. Comparatively less effect was observed in the urban river wetland soils.Phenanthrene is not conducive to nitrogen mineralization except for the improvements observed with high levels of phenanthrene addition to urban river wetland soils. Compared with the control treatment, phenanthrene was beneficial in enhancing urease activities, while no significant effect in rural river wetland soils under high levels of phenanthrene addition was observed. In rural river wetland soils, AOB exhibited higher adaption to phenanthrene, showing the highest adaptability to low concentrations of phenanthrene, while phenanthrene had little effect on the microbial community structure of ammonia oxidation microorganisms in urban river wetlands.更多还原