砷对土壤微生物碳、氮代谢的影响

Effect of Arsenate on Microbiological Metabolisms of Carbon and Nitrogen in Anaerobically Incubated Soil Slurries

通过微生物嫌气培养实验,探讨了砷污染对土壤呼吸作用、反硝化作用、挥发性脂肪酸形成和氮素形态转化等微生物活动过程的影响,以助于理解砷对土壤生态系统中碳(C)、氮(N)的生物地球化学(biogeochemistry)影响.研究结果表明,砷不仅明显抑制微生物活动中CO_2的产生,而且显著降低反硝化细菌的活性.在供试土壤中,砷既促进NO_3—N的消失,同时又减少NO_2—N和NH_4—N的产生,因此,砷可以使NO_3—N转化成除NH_4—N、NO_2N和N_2O—N之外的其他形态的氮,也可以抑制乙酸形成,但促进异丁酸形成.

To understand effects of arsenic pollution on microbial metabolism of carbon and nitrogen in soil, studies on soil respiration, denitrification, volatile fatty acid production and nitrogen transformation as influenced by arsenate were conducted using anaerobically incubated slurries of Danish agricultural soil. Soil respiration (CO2 emission) and denitrification activity (N2O emission) were markedly inhibited by the addition of arsenate (500mg/kg). It is found that addition of arsenate stimulated NO3-N depletion and depressed NO2-N and NH4-N productions in the soil slurries. Therefore, the transformation of NO3-N into nitrogen forms other than NH4-N, NO2-N and N2O-N was stimulated by the addition of arsenate. Arsenate increased acetate production and decreased isobutyrate production.