本文關鍵詞：藍藻暴發(fā)對湖泊生態(tài)系統(tǒng)中內源營養(yǎng)鹽的影響　出處：《南京理工大學》2017年碩士論文　論文類型：學位論文

  更多相關文章： 藍藻水華 內源營養(yǎng)鹽 薄膜擴散梯度技術 釋放機制

【摘要】：近幾十年來,隨著人類活動干擾加劇,湖泊富營養(yǎng)化和藍藻水華成為全球面臨的重大環(huán)境問題。在湖泊外源污染得到有效控制的情況下,沉積物內源營養(yǎng)鹽的釋放是水體持續(xù)富營養(yǎng)化、影響治理成效的關鍵因素。然而,由于缺乏原位技術,很大程度上限制了內源污染的深入研究。本文通過室內模擬藍藻暴發(fā)的條件,利用ZrO-Chelex薄膜擴散梯度(ZrO-ChelexDGT)、微電極技術、Rhizon技術相結合,發(fā)展了一種原位測定沉積物有效磷、鐵、氮的方法。以典型富營養(yǎng)湖泊太湖梅梁灣為研究對象,利用ZrO-Chelex DGT技術探討了營養(yǎng)鹽在藍藻暴發(fā)階段的規(guī)律。主要結果如下:(1)室內模擬藍藻暴發(fā)的條件,利用微電極等技術原位監(jiān)測pH、DO、Eh等參數(shù)的晝夜變化及階段性變化,研究在藍藻水華發(fā)生期間對各參數(shù)的影響。第1-20天藍藻不斷增長繁殖,隨后藍藻開始降解。白天藍藻進行光合作用,pH升高(Max=10.53),溶解氧升高(Max=16.0mg/L),晚上呼吸作用大于光合作用,pH降低(Min=7.57),溶解氧降低(Min=2.5mg/L);沉積物中,隨著沉積物深度的增加,pH、溶解氧、Eh均呈降低的趨勢,但是藍藻組的下降更快。(2)室內模擬藍藻暴發(fā)的條件,利用ZrO-ChelexDGT等技術原位監(jiān)測間隙水、沉積物中有效態(tài)Fe2+的含量及Fe2+的釋放通量,研究藍藻水華期間對沉積物中鐵的影響。上覆水中的Fe2+含量很低,界面下0.5cm間隙水中的Fe2+含量顯著增加;藍藻進行光合作用,pH增加,藍藻組釋放的溶解性Fe2+部分被藍藻吸收供其生長所需,第5天開始白天藍藻組的通量顯著增加。沉積物有效態(tài)Fe2+在上覆水中含量很低,在0-20mm有效態(tài)Fe2+逐漸釋放,隨著深度的增加,有效態(tài)Fe2+含量逐漸減小。(3)室內模擬藍藻暴發(fā)的條件,利用ZrO-ChelexDGT等技術原位監(jiān)測間隙水、沉積物中有效態(tài)磷的含量及磷的釋放通量,研究藍藻水華期間沉積物磷的釋放機制。白天藍藻的光合作用增加上覆水中的pH、DO值,夜里pH、DO值降低,OH-的增加促進沉積物中PO4-的釋放,加上藍藻直接對沉積物中P的吸附降低了間隙水中P的濃度,第5天之后,OH-的增加不再促進沉積物中PO4-的釋放,沉積物中P的釋放主要受到DO以及藍藻降解的控制。(4)間隙水中硝態(tài)氮與氨氮的濃度高于上覆水,存在著由高濃度向低濃度進行的分子擴散作用。上覆水中硝態(tài)氮與氨氮的含量的變化趨勢是一致的,在第1天至第5天呈下降趨勢,第15天顯著增加后又逐漸降低。間隙水中溶解性氮的主要存在形式是氨氮,沉積物不同深度間隙水中的硝態(tài)氮、氨氮的變化規(guī)律是一樣,均是先減小再增加。
[Abstract]:In the past several ten years, with the intensification of human activities, lake eutrophication and cyanobacteria Shui Hua have become a major environmental problem in the world. The release of endogenous nutrients from sediments is a key factor in the sustained eutrophication of water and affects the effectiveness of governance. However, due to the lack of in-situ technology. To a great extent, the study of endogenous pollution is limited. In this paper, the ZrO-Chelex membrane diffusion gradient (ZrO-Chelex) was used to simulate the outbreak of cyanobacteria. A method for in situ determination of available phosphorus, iron and nitrogen in sediments was developed by combining microelectrode technique with Rhizon technique. Meiliang Bay of Taihu Lake, a typical eutrophic lake, was used as an object of study. The rule of nutrient salt in the stage of cyanobacteria outbreak was studied by using ZrO-Chelex DGT technique. The main results were as follows: 1) the conditions for simulating the outbreak of cyanobacteria in laboratory. In situ monitoring of diurnal and periodic changes of pH DOA Eh and other parameters by microelectrode technique was used to study the effects of cyanobacteria Shui Hua on the parameters during the development of cyanobacteria Shui Hua. During the 1-20 days, cyanobacteria continued to grow and reproduce. Then the cyanobacteria began to degrade. During the day, the photosynthesis of cyanobacteria increased the pH value of Maxanthus 10.53 and the dissolved oxygen increased by 16.0mg / L ~ (-1), and the respiration at night was greater than that of photosynthesis. The pH decreases 7.57% and the dissolved oxygen decreases 2.5 mg 路L ~ (-1) 路L ~ (-1) 路L ~ (-1) ~ (-1) 路L ~ (-1); In sediment, with the increase of sediment depth, the pH of dissolved oxygen (DO) Eh decreased, but the decrease of cyanobacteria group was faster. 2) the condition of simulating the outbreak of cyanobacteria in laboratory. In situ monitoring of the content of available Fe2 and the release flux of Fe2 in sediment were performed by ZrO-ChelexDGT and other techniques. The effect of cyanobacteria Shui Hua on iron content in sediments was studied. The Fe2 content in overlying water was very low, and the Fe2 content in 0.5 cm interfacial interstitial water increased significantly. The photosynthetic pH of cyanobacteria increased and the soluble Fe2 released from cyanobacteria was partly absorbed by cyanobacteria for their growth. From the 5th day, the flux of cyanobacteria increased significantly. The content of Fe2 in the overlying water was very low, and the Fe2 released gradually from 0-20mm to 20mm, with the increase of depth. The effective Fe2 content decreased gradually. 3) the condition of simulated cyanobacteria outbreak was simulated in laboratory. The gap water was monitored in situ by using ZrO-ChelexDGT and other techniques. The release mechanism of phosphorus in sediments during the period of Shui Hua was studied. The photosynthesis of cyanobacteria increased the pH value of do in the overlying water during the day and pH at night. The decrease of do increased the release of PO4- from sediments, and the direct adsorption of P by cyanobacteria decreased the concentration of P in interstitial water after 5 days. The increase of OH- no longer promoted the release of PO4- from sediments. The release of P in sediment was mainly controlled by do and the degradation of cyanobacteria. The concentration of nitrate and ammonia in the interstitial water was higher than that in the overlying water. There is a molecular diffusion from high concentration to low concentration. The change trend of nitrate nitrogen and ammonia nitrogen content in overlying water is the same, and it decreases from the first day to the fifth day. The main form of dissolved nitrogen in interstitial water is ammonia nitrogen, and the change of nitrate nitrogen in sediment at different depths is the same as that of ammonia nitrogen, which decreases first and then increases.
【學位授予單位】：南京理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：X524

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