Jiao Lixin

Decay process of Euglena sanguine bloom in Cuihu National Wetland Park, Beijing City

本文研究了北京翠湖湿地公园夏、秋季水华优势藻血红裸藻（Euglena sanguinea）从水华发生到衰亡过程的细胞密度、形态特征及其与环境因子的关系.结果发现，2016年8月下旬至9月中旬血红裸藻密度稳定增加，9月20日藻密度达到峰值5.13×106 cells/L；9月下旬至11月底藻密度显著下降；血红裸藻在衰亡过程中呈现细胞形态由大变小、由细长变为圆形，细胞颜色由深变浅，运动速率由快变慢的趋势，衰亡后形成具透明胶被孢子的休眠体；血红裸藻群落生长的主控因子为水温和pH，其适宜的环境阈值范围为水温23~27℃，pH 7.3~8.0；其受光照强度影响存在分层现象，弱光强区域藻密度相对较低；血红裸藻的衰亡过程与铵态氮浓度呈显著正相关，低浓度时加速衰亡；与总氮浓度呈负相关，衰亡后总氮浓度显著升高；受总磷浓度影响相对较小，与溶解氧浓度无显著相关关系.

Spatial and temporal distribution patterns of loadings of different phosphorous forms in Lake Dianchi

With the help of GIS spatial interpolation, based on the monthly observed data of water yield and phosphorous (P) con⁃ centrations in 36 sampling sites in Lake Dianchi, the loading contributions of different P forms was explored and the spatial and temporal patterns of the P concentrations and loadings were revealed in this paper, aiming at providing evidence for water pollution treatment and inner loading control. The results showed: The changes in total phosphorus (TP) concentrations in the water ranged between 0.13 and 0.64 mg / L, among which particulate phosphorus (PP) covered 72.6% , soluble reactive phosphorus ( SRP) 12.8% , and dissolved organic phosphorus (DOP) 14% . During 2013 the average annual TP loading was 251 t / a, among PP load⁃ ing 190 t / a, SRP 26 t / a, and DOP 34 t / a. TP loading in Lake Dianchi was mostly contributed by PP loading, averaging 76% , and secondly by DOP and SRP, averaging 10% and 13% , respectively. There was a significant difference in seasonal distributions in TP concentrations and loadings and in different P forms. The concentration was characterized with a higher value in summer and autumn in contrast to a relatively low value in winter and spring, while the loading was characterized with a higher value in autumn

Temporal and spatial variations of phosphorus loading and the forms, compositions and contributions in inlet river of Lake Dianchi

The temporal and spatial changes of total phosphorus(TP) and various forms of phosphorus concentration, and the inlet load characteristics were studied in major inlet river of Lake Dianchi. At the same time, the contribution of different forms of phos⁃ phorus from the inlet load was discussed. The results showed: (1) The TP concentrations of the inlet river into Lake Dianchi were between 0.11-1.93 mg / L, and the particulate phosphorus(PP) and dissolved inorganic phosphorus(DIP) forms were the main part. (2) The TP loading of the inlet rivers of Lake Dianchi was 280.51 t / a, and DIP was the main form in most rivers into the lake with an average contribution of 43.48% . PP form into the lake load followed with an average contribution of 31.64% . DOP form into the lake load was relatively low with an average contribution of 24.88% . (3) DIP load into the lake with the higher con⁃ tribution value appeared in dry season (March, April and November), which the average contribution rate reached to 55.30% . Higher values of PP forms into the lake load occurred in January and July, with the average contribution of 56.14% . Change of the DOP load into the lake was relatively low, with the highest value appeared in December and its contribution was 21.85% . (4) The river pollution load into Lake Dianchi not only needs to be considered the contribution of the dissolved inorganic phosphorus into the lake, but also to be paid an attention on the dissolved organic phosphorus and particulate phosphorus loading. During the process of