基塘系统底泥氮、磷释放规律的研究.pdf

摘要基塘系统底泥氮、磷释放规律研究专业:环境科学硕士生:邝建艺指导教师:金辉副教授摘要基塘系统是一种相对封闭的人工生态系统,在适当条件下,氮、磷能从水体沉积物中释放出来,为水生生物的生长提供必要的营养元素;同时,氮、磷也是藻类生长的主要限制性营养元素,过量会加剧水体的富营养化,从而破坏基塘系统的生态平衡,造成一定的经济损失。为此,有必要研究水体沉积物中氮、磷向上覆水体释放的影响因素,并由此找出相应的控制水体富营养化的对策。通过在广东顺德实地勘查,在不同的两个鱼塘采集底泥样品,本文作者首先进行了底泥的性状以及氮磷污染物分析,确定氮磷污染物的形态特征、浓度大小以及分布状况。然后,在实验室模拟基塘系统,分析在不同的溶解氧浓度、温度、pH值及水动力状态条件下,基塘底泥释放出来的氮磷污染物的存在形态和浓度。运用EXCEL软件对水体中的氮磷浓度与水体溶解氧浓度、温度、pH值及水动力状的关系进行分析,寻求氮磷污染物的释放规律。其研究结果如下: (1)溶解氧对底泥中氮、磷的释放影响明显,当上覆水体处于富氧条件时,总氮、硝态氮和氨氮的释放量均大于缺氧条件时;而磷的释放量在上覆水体处于缺氧条件时比富氧条件时的大。(2)随着上覆水体温度的升高,底泥中总氮、硝态氮、氨氮和磷的释放量都随之增加。(3)在上覆水体pH值为2~13的范围内, 底泥总氮和氨氮释放量随着pH值增大而减少,而硝态氮释放量则随着pH值增大而缓慢增大;在上覆水呈酸性和碱性条件下,磷的释放量均高于中性条件下的释摘要放量,而且磷释放量在碱性条件下大于酸性条件。(4)加强上覆水体的扰动剧烈程度有利于氮、磷的释放。基塘养殖者可以把本文的研究结果作为控制基塘水体富营养化的参考资料, 从而提高基塘系统的生态效益及经济效益。关键词:基塘,底泥,氮,磷 ABSl毗CT Study on Release ofNitrogen andPhosphorus from Sediments intheDike—pond Ecosystem Major:Environment Science Name:Kuang Jianyi Supervisor:Jin Hui ABSTRACT The dike—pond ecosystem is akindofartificialecosystem which isrelatively propercondition,nitrogen andphosphorus can bereleasedfrom sediments toprovide necessary nutritionforaquicolous themeanwhile,they are themain restrictiveelements forthegrowth are toomuch,the trophic state would beworsen,the balance ofecology would bedestroyed,and there would be some economical ,it isnecessary tostudy thefactorsaffecting Nand Ptobe releasedfrom thesediments tothewater some relevantcountermeasure must befoand outtocontrolthetrophic stateofthewater. Perambulating inShunde,Guangdong,the author sampled some sediment from two analyzed theproperties ofthesediment toconfirm the conformation,concentration and distributing of Nand thelab,he simulated thedike·pond ecosystem toanalyze theconformation and concentration of PandNindifferentDO condition,different temperature condition,different pH condition anddifferenthydrodynamics hetried tofind outthelawof thereleaseofNand只thoue)t studying the