溶解氧和光照对狐尾藻衰亡释放氮磷碳的影响

将杀青后的狐尾藻(Myriophyllum spicatum)切成0.5～1cm段浸泡于添加氯仿(抑制微生物活性)的装水烧杯中,置于人工气候箱(温度为5℃),考察光照和溶解氧对因植物组织溶解而导致的氮磷碳释放的影响。研究结果表明曝气组总氮释放量平均3.33mg/L,比不曝气组高6.39%。总磷释放量平均15.07mg/L,比不曝气组低50%以上。COD平均释放量66.83mg/L,为不曝气组2倍以上。(1)曝气抑制了硝氮释放。在搅拌作用下,植物残体和水溶液充分碰撞与接触,加速植物残体中氮和碳向水中转化,导致曝气组总氮、氨氮、有机氮和COD升高。曝气组植物残体破碎导致表面积增加对磷吸收的促进程度强于对附着作用的降低以及植物残体磷释放作用的增加,综合作用下导致水中磷浓度降低。曝气抑制了硝氮、总磷、溶解性总磷和溶解性无机磷释放。(2)有光照组总氮、总磷和COD平均浓度分别为3.13,30.53和32.51mg/L,分别为无光照组的1.24,3.28和2.46倍。光照促进狐尾藻总氮、氨氮、硝氮、总磷、溶解性总磷、溶解性无机磷及碳的释放,但抑制有机氮释放。

Effect of Dissolved Oxygen and Illumination on Nitrogen, Phosphorus and Carbon Release of Myriophyllum spicatum

Myriophyllum spicatum which was killed and cut into small section in length of 0.5～1cm was soaked in water beaker adding chloroforms in artificial climate room at temperature of 5℃, aiming to investigate the influence of illumina-tion and dissolved oxygen (DO) on pollutant release resulted from the dissolved plant tissues. Average release of TN con-centration under aeration conditions was 3.33mg/L, 6.39% higher than the non-aeration group. Average release of TP concentration was 15.07mg/L, 50% lower than the non-aeration group. Average COD concentration releasing amount was 66.83mg/L, which was more than 2 times of non-aeration group. Aeration suppressed the release of nitrate. Under mixing functions, the abundant collision and keeping in touch of plant residue and aqueous solution accelerated nitrogen and car-bon of plant residue transfer into water, resulted in rising of TN, ammonia nitrogen, organic nitrogen and COD. Aeration suppressed the release of nitrate, TP, dissolving total phosphorus and dissolving inorganic phosphorus. Average TN con-centration of illumination group was 3.13mg/L, which was 1.24 times of group without illumination. TP concentration of 30.53mg/L in illumination group was 3.28times of the group without illumination. COD concentration of 32.51mg/L was 2.46 times of the group without illumination. The illumination had promoted the release of TN, NH_3-N, NO_3-N, TP, DTP, DIP and C of Myriophyllum spicatum, but had suppressed the release of Org-N.