pH对闽江河口湿地沉积物氮素转化关键过程的影响

Effects of pH on the Key Nitrogen Transformation Processes of the Wetland Sediment in the Min River Estuary

以闽江河口湿地沉积物为研究对象,通过单变量的沉积物培养试验(pH=2.5,3.5,4.5,5.5,6.5),研究pH对湿地沉积物氮元素硝化、反硝化、矿化3个关键过程的影响。结果表明:低pH(pH=2.5)对硝化活性有明显的抑制作用,其余pH对沉积物的硝化速率影响不大,硝化细菌的数量和活性在强酸条件下限制明显。随时间推移,沉积物反硝化速率减小,反硝化活性增强。偏酸条件对反硝化活性有一定抑制作用,主要由于沉积物中反硝化细菌在酸性条件下不活跃或耐酸细菌数偏少。不同pH条件下,矿化速率基本无规律可循,表明pH对湿地沉积物矿化过程无直接影响。

Using the single variable laboratory experiment,the wetland sediment in tidal flats areas of Min river estuary were collected to research the effect of pH on the nitrification,denitrification and mineralization processes of the nitrogen（the pH conditions were setting at 2.5,3.5,4.5,5.5,6.5,respectively）.The results suggested that：In the nitrification process,lower pH（the pH was 2.5）showed the obvious inhibition on the nitrification activity,however,at other pH conditions,the influence on the nitrification rate of the sediment varied little.Which indicated that the number and the activity of the nitrifying bacteria were typical limited under the strong acid surrounding.In the denitrification process,the denitrification rate of the sediment decreased with time but the denitrification activity increased.Besides,the strong acid condition（the pH was 2.5）in some degree had inhibitory effect on the denitrification activity.Results indicated that denitrifying bacteria in the sediment was not active or the acid resistance bacteria was rare under strong acid condition.Finally,mineralization of the nitrogen was researched and no universal rule was found between the pH and the mineralization rate,which showed that the pH had no direct effect on the mineralization process of sediment in the wetland.