Study On Phytoplankton And Water Environmental Factors In Libo Daqikong And Xiaoqikong

The Daqikong and Xiaoqikong scenic spots are an important part of the Libo World Natural Heritage Site.Its wonderful mountains and beautiful waters have become the external business card of the Libo World Natural Heritage Site,attracting thousands of tourists,but at the same time human activities have brought negative effects on the water body.The current research reports on the aquatic organisms and water quality of the Libo World Natural Heritage Site are relatively sporadic.Therefore,it is for the world to fully understand the water quality status of the water body and assess the possible water quality risks of the Daqikong and Xiaoqikong Provide basic data for sustainable use and protection,management and decision-making of water resources in natural heritage sites.In this study,based on the hydrological characteristics of the small and large seven holes,combined with the distribution of the main scenic spots,and according to the phytoplankton and water quality survey operation specifications,4 observation and sampling sites were set up in Daqikong,and 8 observation and sampling sites were set in Xiaoqikong.From August 2016 to May 2018,a total of 8 on-site observations and sampling were carried out at a frequency of once every three months.A total of 192 phytoplankton qualitative and quantitative samples were obtained,and a total of 288 water quality physical and chemical index samples were passed through the experimental microscope.Inspection and determination of water quality physical and chemical indicators,and the following research conclusions are obtained:1)There are abundant phytoplankton species in Daqikong and Xiaoqikong.A total of 7 phyla,9 classes,25 orders,53 families,96 genera and 255 species(including variants)of algae were detected,of which 161 species(including variants)were detected in Xiaoqikong.In 6 phyla,8 classes,20 orders,43 families and 70 genera.143 species(including variants)were detected in Daqikong,belonging to 65 genera,41 families,5 phyla,7 classes,21 orders.(2)There are certain similarities and differences in the physical and chemical factors of water bodies in Daqikong and Xiaoqikong scenic spots.The similarities are: water temperature and air temperature show a significant positive correlation;water temperature and DO value show a significant negative correlation;water temperature and altitude show Negative correlation;water temperature and total nitrogen content show a significant positive correlation;total nitrogen content and water dissolved oxygen show a significant negative correlation.The similarity is mainly due to the closeness of the two locations and the similar climatic environment.The difference is: large and small seven holes have different rules in nutrient content,which is mainly related to the difference in hydrological types in the large and small seven holes.The hydrological type of the big seven holes is single,so the nutrient content changes in each site are more obvious.From the upstream to the downstream,the hydrological types are complicated,and the regularity of nutrient content is not obvious.(3)The water quality of Daqikong and Xiaoqikong is gradually getting better,but the chemical oxygen demand and total nitrogen content,part of the time and sampling location are still in the state of exceeding the standard,and it does not meet the national water quality standard(ie Total nitrogen content <1.0mg/L,COD content <20mg/L),the water quality of Xiaoqikong is better than that of Daqikong,and there are more standard projects than Daqikong.(4)Based on the analysis of the correlation between phytoplankton and physical and chemical indicators of the water body,the phytoplankton species composition of Daqikong and Xiaoqikong is mainly related to water depth and flow velocity;cell density is mainly related to the nutrient content of the water body.