不同扰动下底泥磷的转化机制

发布时间：2018-01-23 01:26

本文关键词： 不同扰动底泥磷迁移转化不同形态外源磷　出处：《苏州科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：磷在水体中如何迁移转化是个很值得研究的课题,现在,在构建浅水湖泊磷迁移转化理论体系过程中,有诸多关键的科学问题尚未解决,基于以往的研究主要集中在上覆水磷浓度形态的变化上而忽视了底泥界面对于水体磷迁移转化的作用,仅此只能解决了上覆水中磷形态变化的科学问题。而实际上物理或者底栖生物对底泥产生扰动,都可以在横向或者纵向使得底泥的微环境和微界面发生改变,而这样一种改变对底泥磷的转化可能造成重要的影响。因此,在揭示“底泥磷怎样转化的机制”科学规律方面仍需进一步研究。本文主要从两个方面研究问题,从仅存在内源磷条件下,重点研究不同扰动下底泥的微环境和磷形态的横向变化,辅之以上覆水的研究,再结合再投加外源磷情况下,纵向研究各组不同扰动下实验过程中底泥磷的动态变化过程和上覆水磷的迁移过程。综合分析底泥磷单纯和组合叠加作用,以不同底泥扰动状态下底泥磷迁移转化过程机制作为突破重点,从而揭示内源磷再生和转化的行为过程机制等科学问题,能有利于整个浅水湖泊磷迁移转化体系完善,可以从最基础理论层面进一步为浅水湖泊富营养化引发机制和预防策略的制定提供理论参考依据。结果表明,组合扰动下加入河蚬会进一步增大了底泥的pH,对pH的影响范围扩至深度为20~30mm,而河蚬和藻类的共同加入会导致底泥的pH进一步扩大。随着扰动因素的增加,上覆水及底泥内部溶解氧含量明显降低。河蚬的引入,增加了内源磷释放趋势,导致上覆水中不同形态磷含量明显增加(但部分磷可能来源于河蚬的排泄物),而藻类的加入对内源磷释放的诱导作用更持久,间隙水中DIP含量的降低则充分证明了这一点。随着扰动因素的增加,内源磷释放幅度加大,并且由NH4Cl-P转化为Fe/Al-P的比重也逐渐增加。河蚬的加入使内源磷释放幅度增大的主要原因是河蚬生物引灌、大量消耗溶解氧和增大pH。在外源磷输入下,物理扰动能进一步使上覆水中各种形态磷含量降低,而生物扰动和组合扰动的作用与之相反。物理扰动能减少间隙水中DIP的含量,但减少程度不如生物扰动组和组合扰动组高。3种扰动都能促进Fe/Al-P的形成,其中,物理扰动的Fe/Al-P各层平均形成量最大,3种扰动都有利于Ca-P的生成,但物理扰动促进作用最大。物理扰动组AAP含量一直在减小,说明物理扰动明显促进了AAP向闭蓄态的Fe/Al-P或者Ca-P转化,而生物扰动和组合扰动在一定程度上也能促进AAP向闭蓄态磷的转化。
[Abstract]:How to transport and transform phosphorus in water is a topic worthy of study. Now, in the process of constructing the theoretical system of phosphorus transport and transformation in shallow lakes, there are many key scientific problems that have not been solved. Based on the previous studies on the change of phosphorus concentration in overlying water, the effect of sediment interface on phosphorus transport and transformation in water was neglected. Only this can solve the scientific problem of phosphorus form change in overlying water. In fact, physical or benthic disturbance to sediment can change the microenvironment and microinterface of sediment both horizontally and longitudinally. Such a change may have an important impact on the transformation of phosphorus in sediment. Therefore, it is still necessary to further study the scientific law of "how to transform phosphorus in sediment". Under the condition of only endogenous phosphorus, the microenvironment and the lateral change of phosphorus form of sediment under different disturbances were studied, supplemented by the study of overlying water, and then combined with the addition of exogenous phosphorus. The dynamic change process of phosphorus in sediment and the transport process of phosphorus in overlying water were studied longitudinally under different disturbances. The simple and combined superposition of phosphorus in sediment were analyzed synthetically. The mechanism of phosphorus migration and transformation in different sediment disturbance was taken as the key point to reveal the behavior mechanism of endogenous phosphorus regeneration and transformation. It can be beneficial to the improvement of phosphorus transport and transformation system of the whole shallow lake, and can provide theoretical reference for eutrophication initiation mechanism and prevention strategy of shallow water lake from the most basic theoretical level. The results show that. The pH of sediment was further increased by adding Corbicula flumeracea under combined disturbance, and the range of influence on pH was extended to 20mm 30mm. With the increase of disturbance factors, the content of dissolved oxygen in the overlying water and sediment decreased obviously. The introduction of Corbicula fluminea increased the release trend of endogenous phosphorus. As a result, the phosphorus content of different forms in the overlying water increased significantly (but some phosphorus probably originated from the excreta of Corbicula fluminea, and the effect of algal addition on endogenous phosphorus release was more lasting. The decrease of DIP content in interstitial water fully proves this. With the increase of disturbance factors, the release range of endogenous phosphorus increases. And the proportion of the conversion from NH4Cl-P to Fe/Al-P also gradually increased. The main reason for the increase of endogenous phosphorus release was the biological drainage and irrigation of Corbicula flumba. Under the input of exogenous phosphorus, the physical disturbance can further reduce the content of various forms of phosphorus in the overlying water. The effect of biological disturbance and combined disturbance is opposite. Physical disturbance can reduce the content of DIP in interstitial water. However, the reduction degree is lower than that of biological disturbance group and combined disturbance group. 3 kinds of disturbances can promote the formation of Fe/Al-P. Among them, the average formation amount of Fe/Al-P in physical disturbance layer is the largest. All the three kinds of disturbances are favorable to the formation of Ca-P, but the physical disturbance has the greatest effect. The AAP content of the physical disturbance group is decreasing all the time. The results show that physical disturbance can obviously promote the transformation of AAP to Fe/Al-P or Ca-P, while biological disturbance and combined disturbance can also promote the conversion of AAP to closed storage phosphorus to some extent.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52

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