洱海罗时江湿地表层沉积物氨氮释放特征及影响因素
Release characteristics and influencing factors of ammonia nitrogen in the surface sediment of the Luoshijiang Wetland upstream of the Erhai Lake
王化 1宝冬润 1梁启斌 1王艳霞 1李晓琳 1侯磊1
作者信息
- 1. 西南林业大学生态与环境学院,昆明,650224
- 折叠
摘要
以洱海上游的罗时江湿地为研究对象,基于为期半年的野外监测,弄清湿地水体和表层沉积物中氨氮(NH3-N)的时空分异规律,借助摇瓶试验法探究湿地入口沉积物NH3-N的释放特征及水体离子强度(IS)和pH的影响.结果表明:(1)罗时江湿地上覆水和表层沉积物NH3-N浓度变化范围分别为0.14-1.45 mg·L-1 和 0.23-8.89 mg·kg-1,干湿季差异均不显著(P＞0.05);上覆水和表层沉积物NH3-N浓度均沿水流方向显著下降(P＜0.05),出水口 NH3-N平均浓度分别是入水口的59.2％和49.9％,湿地对水体NH3-N有截留效果.(2)模拟试验条件下,沉积物NH3-N累积释放量的变化范围为412.9-653.7 mg·kg-1,随提取次数的增加单次释放量逐渐降低;NH3-N累积释放量湿地人口显著高于其他样点,干季高于湿季.(3)上覆水IS升高促进沉积物NH3-N的持续释放,增加快速释放NH3-N占比;上覆水处于弱酸条件下更利于沉积物NH3-N的持续释放,同时提高快速释放NH3-N占比.研究结果显示,表流湿地入水口沉积物是NH3-N的主要富集场所,水化学条件变化导致NH3-N向上覆水释放可能引起二次污染.
Abstract
The Luoshijiang Wetland,located in the upstream of the Erhai Lake,was selected as the research object.The spatiotemporal variations of ammonia nitrogen(NH3-N)in the water body and surface sediment of the wetland were clarified based on the half-year field monitoring,and the release characteristics of NH3-N in the wetland inlet sediment and the effects of water ionic strength(IS)and pH were explored via flask-shaking test.The results showed that:(1)The NH3-N concentrations in the overlying water and surface sediment of the Luoshijiang Wetland varied from 0.14 mg·L-1 to 1.45 mg L-1 and 0.23 mg·kg-1 to 8.89 mg·kg-1,respectively,with no significant difference in dry and wet seasons(P＞0.05).The NH3-N concentrations in the overlying water and surface sediment decreased significantly along the flow direction(P＜0.05),and the average NH3-N concentration at the outlet was 59.2％and 49.9％of that at the inlet,respectively.The wetland showed a retention effect towards NH3-N in the water body.(2)Under the simulated test conditions,the cumulative release amount of NH3-N from sediment varied from 412.9 mg·kg-1to 653.7 mg·kg-1,and the single release amount gradually decreased with the increase of extraction times.The cumulative release amount of NH3-N at the wetland inlet was significantly higher than that at other sample sites,and was higher in the dry season than in the wet season.(3)The increase of IS in the overlying water promoted the continuous release of NH3-N from sediment and increased the proportion of rapid release NH3-N.The weak acid condition of the overlying water facilitated the continuous release of NH3-N from sediment,and the proportion of rapid release NH3-N was also increased.The results indicated that the sediment at the inlet of the surface flow wetland was the main enrichment site of NH3-N,and the change of water chemical conditions might lead to the release of NH3-N to the overlying water,resulting in potential secondary pollution.
关键词
表流人工湿地/沉积物氨氮/释放特征/上覆水pH和离子强度影响Key words
free water surface constructed wetland/ammonia nitrogen in sediment/release characteristics/effects of pH and ionic strength in the overlying water引用本文复制引用
基金项目
国家自然科学基金(22066023)
国家自然科学基金(41663016)
出版年
2024
NETL
NSTL
万方数据