Hie effects of Limnodrilus hoffmeisteri bioturbation on nitrogen releasing from sediments of the East Lake Dongting, with the different densities and environments were studied in this paper. Hie results showed that bioturbation of L hoffmeisteri had a good accelerating effect on nitrogen release from sediments, which was caused mainly by ammonium release. When the density of L. Hoffmeisteri was at 1 and 2 ind. /cm2 , the concentrations of total nitrogen in overlying water were increased by 15% and 32% respectively comparing to the control test. Appropriate increasing of temperature was helpful for vital movement of L hoffmeisteri, which caused that total nitrogen release increment were increased by 23% and 69% respectively when temperatures were 15 % and 25 ℃ compared to the cotrolling 5 X,. Adversity stress on L. Hoffmeisteri, induced by acidic and alkali environments, enhanced its bioturbation effect and also accelerated nitrogen releasing. In comparison with a condition of pH 7, total nitrogen release increment were increased by 32% and 41% when pH values were 5 and 9, respectively. Total nitrogen release increment in hypoxia was 1.52 fold compared to the aerobic environment, which indicated that L hoffmeisteri had good adaptability and survivability to hypoxia environment in which bioturbation was stronger than in aerobic environment.%研究了不同投放密度和不同环境条件下水丝蚓的生物扰动对东洞庭湖沉积物氮释放的影响.研究表明:水丝蚓的生物扰动作用对沉积物氮释放有明显的促进作用,水丝蚓生物扰动促进下的NH4+-N释放构成沉积物氮释放的主要动因.与未投放水丝蚓的空白组相比,当水丝蚓密度为1和2 ind./cm2时,上覆水中总氮的浓度分别增加了15％和32％.温度的升高,会加大水丝蚓生物扰动对氮释放的影响,与5℃相比,15和25℃下总氮释放增量分别提高了23％和69％.在酸性或碱性环境下,水丝蚓的生物扰动加强,会提高对氮释放的促进作用,当pH为5和9时,总氮释放增量比pH为7时分别提高32％和41％.水丝蚓对缺氧环境有良好的适应能力,在缺氧环境下,水丝蚓的生物扰动会增强,总氮释放的增量是好氧状态下的1.52倍.
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