腐解黑藻生物量对高硝态氮水体氮素的影响

采用常见沉水植物黑藻为试验材料,引入太湖底泥并设定上覆水初始ρ(硝态氮)为15 mg/L,模拟初春沉水植物大规模腐烂时的温度,开展为期32 d的黑藻腐解试验研究. 结果显示,黑藻腐解对水体中ρ(氨氮)与ρ(硝态氮)之和的影响呈U字型,试验条件下黑藻腐解生物量为2.0 g(相当于0.111 kg/m2)时,水体中ρ(氨氮)与ρ(硝态氮)之和最低. 随着黑藻的腐解,释放进入水体的有机质和氮素增加,但同时也提高了水体中的ρ(TOC)/ρ(硝态氮)值,降低了Eh,提高了微生物的活性,因此有利于反硝化反应的发生. 

Effect of Hydrilla verticillata Decomposition Biomass on Nitrogen Content in Water Containing High Concentration of Nitrate

A decomposition experiment with a common submerged macrophyte, Hydrilla verticillata, was carried out for aperiod of 32 days, by introducing sediments from Taihu Lake at ρ(NO₃－) content of 15 mg/L in the overlying water. The temperature of early spring was simulated when submerged plants were decomposed in large-scale. The results showed that the impact of Hydrilla verticillata decomposition on nitrogen concentration (ρ(NO₃－) and ρ(NH₄＋)) in water was U-shaped. The nitrogen concentration was lowest under the experimental conditions when biomass decomposition was 2.0 g (equivalent to 0.111 kg/m2). With the decomposition of Hydrilla verticillata, the release of organic matter and nitrogen into the water increased; however, at the same time, the ρ(TOC)/ρ(NO₃－) ratio increased, E_h lowered, and microbial activity increased, which were conducive to the occurrence of denitrification.