底泥覆盖对氮磷释放及休眠蓝藻复苏的影响

来源：中国环境科学杂志2024年第11期北京时间：

作者：杨诗幼, 唐炳然, 罗竣潇, 梁嘉良, 何强, 李宏

单位：重庆大学, 三峡库区生态环境教育部重点实验室, 重庆 400045

摘要：To explore the effect of nutrients removal on the recruitment of the dormant cyanobacteria in sediments as well as the mechanism involved, we conducted a microcosm experiment, in which lanthanum modified bentonite and fly ash-based zeolite were used as nitrogen and phosphorus adsorption materials. Specifically, a control group, nitrogen controlling group (capping the surface sediment with fly ash based zeolite), phosphorus controlling group(capping with lanthanum modified bentonite), and a nitrogen and phosphorus double controlling group (capping with fly ash based zeolite mixed with lanthanum modified bentonite) were set up. The results showed that the concentration of phosphorus and ammonia nitrogen in the pore water of the sediments in control group reached 0.732 and 0.044mg/L after 120 days incubation, while were reduced by 97.81% and 65.91% in the phosphorus controlling group and nitrogen controlling group, respectively. This indicated that these treatments inhibited the release of sedimental phosphate or ammonia nitrogen. In contrast, nitrogen and phosphorus double controlling can achieve efficient reduction in both nitrogen and phosphorus release, as the total phosphorus and total nitrogen concentration in the overlying water showed 33.33% and 57.18% reduction in comparison with their initial value. In addition, Capping the sediment increased the relative abundance of denitrification microorganisms (e.g. Thiobacillus, Sulfuricurvum) and nitrate reduction reaction microorganisms (e.g. norank_f_Anaerolineaceae) in the surface sediment. At the end of the experiment, the concentration of chlorophyll a in the control group was 24.36µg/L, which was 16.13, 6.07 and 32.48 times of that in the nitrogen controlling group, phosphorus controlling group, and nitrogen and phosphorus double controlling group, respectively. The relative abundance of cyanophyta in the nitrogen, and nitrogen and phosphorus double controlling group were decreased by 12.24% and 10.16%, respectively. While the relative abundance of diatomata was higher than that in control group, with 2.34 and 2.33 times of the abundance recoded, respectively. This suggested that the phytoplankton diversity was substantially modified.

关键词：镧改性膨润土,粉煤灰基沸石,蓝藻,复苏,氮,磷

基金资助：国家自然科学基金资助项目(52370199);重庆市技术创新与应用发展专项重点项目(CSTB2023TIAD-KPX0092)