摘要
为探究蓝藻(Cyanobacteria)、芦苇(Phragmites australis)残体及其混合分解过程对水质的影响,在实验室进行了模拟实验,共设置B、C、D三个处理组,分别加入2 g蓝藻、2 g芦苇及蓝藻、芦苇各2 g,监测其分解过程中水体溶解氧(DO)、氧化还原电位(Eh)、总氮(TN)和总磷(TP)等理化指标变化情况。结果表明:加入草藻残体后,水体DO和Eh迅速下降。蓝藻-芦苇混合分解组一直处于厌氧状态,水体Eh值最终稳定在-150 m V左右,水体具极强还原性;同时,厌氧强还原条件又加速了草藻残体分解过程,促进了营养盐向上覆水的释放,B、C、D组TN含量分别于实验第2 d、第7 d和第2 d达到峰值,是初始值的5倍、2倍和6倍,水体无机氮以NH+4-N为主;厌氧环境下,间隙水中磷酸盐向上覆水迁移转化以及沉积物中Fe-P的还原释放,使水体TP和Fe2+浓度升高,TP平均增长速率分别为0.38、0.10、0.52 mg·L^(-1)·d^(-1),Fe2+最高浓度达到1.62 mg·L^(-1)。研究表明,蓝藻和芦苇在分解过程中会向水体中释放大量营养盐,引发"湖泛"或"黑水团"现象,加剧水体富营养化。因此,应当密切关注芦苇丛及近岸带漕沟等区域,避免引发水质快速恶化等问题。
Cyanobacteria and Phragmites australis from Lake Taihu were collected to simulate the influence of decomposition processes of higher aquatic plants and algae on water quality in the laboratory. Cyanobacteria, Phragmites australis, and cyanobacteria and Phragmites australis samples of 2 g each were arranged into groups B, C, and D, respectively, for three treatments to continuously monitor the concentra-tion variations of total nitrogen（TN）, total phosphorus（TP）and other physico-chemical parameters of water. Results showed that DO and Eh rapidly decreased after adding cyanobacteria and aquatic plants. The mixed decomposition group remained anaerobic throughout the experiment, and Eh values of the water body were finally stabilized at about-150 m V, suggesting that the water was in a strongly reducing state. Simultaneously, the strong anaerobic and reducing environments accelerated the decomposition of cyanobacteria and Phragmites australis, and promoted the release of nutrients to the overlying water. The TN contents of B, C, and D groups peaked on the 2 nd, 7 th, and 2 nd days, and their maximum concentrations were 5, 2 times, and 6 times that of the control, respectively. Inorganic nitrogen was dominated by NH＋4-N. Under anaerobic conditions, the migration and transformation of phosphate from the interstitial water to the overlying water and the reduction of Fe-P in the sediments increased the concentrations of TP and Fe2＋in the water. The average increasing rates of TP were 0.38,0.10 mg·L^（-1）·d^（-1）, and 0.52 mg·L^（-1）·d^（-1）, and the highest concentration of Fe2 ＋was 1.62 mg·L^（-1）. These observations clarified that a large amount of nutrients was released during the decomposition processes of higher aquatic plants and algae, which intensified eutrophication.Therefore, it is necessary to pay close attention to reeds and the shoreline of eutrophic lakes to avoid rapid deterioration of water quality.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2018年第2期302-308,共7页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(41573061)
国家水体污染控制与治理科技重大专项(2012zx07101-008-02)
江苏省太湖水环境综合治理科研项目(JSZC-G2014-212)
江苏省研究生科研与实践创新计划项目(KYCX17_1064)
关键词
水生植物
蓝藻
分解
水质
太湖
aquatic plants
cyanobacteria
decomposition
water quality
Lake Taihu
