| 蓝藻水华对太湖水柱反硝化作用的影响 |
| 摘要点击 2362 全文点击 1012 投稿时间：2018-08-06 修订日期：2018-09-28 |
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| 中文关键词 太湖 蓝藻浓度 15N同位素添加 膜进样质谱仪(MIMS) 反硝化速率 |
| 英文关键词 Taihu Lake cyanobacteria concentration 15N isotope addition membrane inlet mass spectrometer(MIMS) denitrification rate |
| 作者 | 单位 | E-mail | | 刘志迎 | 江南大学环境与土木工程学院, 无锡 214122 | 970412850@qq.com | | 许海 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 太湖湖泊生态系统研究站, 南京 210008 | | | 詹旭 | 江南大学环境与土木工程学院, 无锡 214122 | xuzhan@jiangnan.edu.cn | | 朱广伟 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 太湖湖泊生态系统研究站, 南京 210008 | | | 秦伯强 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 太湖湖泊生态系统研究站, 南京 210008 | | | 张运林 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 太湖湖泊生态系统研究站, 南京 210008 | |
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| 中文摘要 |
| 反硝化作用是湖泊水体最主要的脱氮过程，对减轻湖泊的氮素污染和富营养化控制具有重要意义.蓝藻水华暴发和衰亡可能会通过改变水体氮素循环途径及微环境来促使反硝化作用直接在水柱中发生，加速氮的去除.为了验证这一假设，取太湖湖水添加不同生物量的蓝藻和连续10 d的NO3--N、PO43--P营养盐，进行蓝藻生长与降解对反硝化影响的模拟实验，测定蓝藻水华期水体藻类生物量和各形态氮浓度的动态变化，同时利用15N同位素添加培养结合膜进样质谱仪（MIMS）实时定量测定反硝化速率.结果表明，蓝藻在生长期吸收氮素转变为颗粒氮，在衰亡期藻细胞通过降解矿化释放了大量的NH4+-N，继而转化为NO3--N，为反硝化作用提供底物，是大幅度促进水体反硝化作用的关键；反硝化速率（以N2计，下同）最高达到（1614.52±301.57）μmol·（m2·h）-1，是同时期最低蓝藻生物量组反硝化速率［（534.45±242.18）μmol·（m2·h）-1］的3倍，实验结束时添加初始蓝藻生物量倍数最高组的TN去除率达最高（40.02%），是未添加蓝藻组TN去除率（17.72%）的2.26倍，说明蓝藻堆积会显著促进反硝化作用的强度，加速水体氮素的去除.蓝藻衰亡时反硝化速率的快慢受NH4+浓度的影响显著，表明附着在藻团的微生物的耦合硝化-反硝化作用是氮盐去除的主要途径.本研究结果表明，水华蓝藻生长期快速吸收氮素转变为颗粒氮，蓝藻死亡降解后通过耦合硝化-反硝化作用加速氮素去除，这可能是太湖夏季氮素浓度降低的原因之一. |
| 英文摘要 |
| Denitrification is the most important nitrogen removal process in lake waters, and is of great significance for mitigating nitrogen pollution and controlling eutrophication in lakes. The outbreak and decline of cyanobacterial blooms may promote denitrification directly in the water column by changing the nitrogen circulation pathway and microenvironment of the water body, and accelerate the removal of nitrogen. In order to verify this hypothesis, the cyanobacteria with different biomass and the NO3--N, PO43--P nutrient for 10 days were taken from Taihu Lake water to simulate the effects of cyanobacteria growth and degradation on denitrification. The dynamic changes of algal biomass and various forms of nitrogen concentration were simultaneously determined by 15N isotope addition culture combined with membrane inlet mass spectrometer (MIMS) for real-time quantitative determination of denitrification rate. The results showed that cyanobacteria absorbed nitrogen into particle nitrogen during the growth period. During the decay period, algae cells released a large amount of NH4+-N by degrading mineralization, which was then converted into NO3--N to provide a substrate for denitrification. That is the key to promoting denitrification in water; the denitrification rate (as N2) reaches (1614.52±301.57)μmol·(m2·h)-1, which is three times higher than the denitrification rate[ (534.45±242.18)μmol·(m2·h)-1]of the lowest concentration cyanobacterial group at the same time. At the end of the experiment, the highest rate of TN removal was highest in the group with the highest initial biomass of cyanobacteria (40.02%), which was 2.26 times of the TN removal rate (17.72%) in the control, indicating that cyanobacterial accumulation can significantly promote the intensity of denitrification and accelerate the removal of nitrogen in water. The rate of denitrification in the decline of cyanobacteria is significantly affected by the concentration of NH4+-N, indicating that the coupling of nitrification-denitrification of microorganisms attached to algae is the main route of nitrogen removal. The results study indicate that the cyanobacteria bloom rapidly during the growth period. Nitrogen is converted into particle nitrogen. The degradation of cyanobacteria is accelerated by coupled nitrification-denitrification, which may be one of the reasons for the decrease of nitrogen concentration in Taihu Lake. |
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