Composition Of Plankton And Analysis Of Water Quality In Building Area Of The Puqian Bridge In 2017

The Puqian bridge in Hainan was located in Dongzhai Bay,the east and north of Haikou.The Peqian Bridge in Hainan was a sea-crossing bridge over the Dongzhai Bay,and connects two cities,namely Tashi of Haikou and Puqian of Wenchang.To study composition of plankton species and evaluate the water condition,investigation were undertaken from the winter of 2016 to the winter of 2017,and deployed 8 monitoring-sites.Monitoring sites were divided into three areas,such as inside the mangrove,outside the mangrove and nearby mangrove.Combined plankton composition and monitoring result of water quality,reasonably analyzed whether bridge building affects local water quality and ecosystem,and then provides reference for kinds of constructions whether affects local water quality and ecosystem.77 species of phytoplankton were identified in the Puqian bridge from the winter of 2016 to the winter of 2017.77 species belong to 52 genus of 5 phylum.Bacillariophyta was the main phytoplankton,and the following was Pyrrophyta,Chlorophyta,Cyanophyta and Euglenophyta.Bacillariophyta has 44 species of 27 genus,and accounted for 57.14%of the whole phytoplankton.Pyrrophyta has 15 species of 8 genus,and accounted for 19.48%of the whole phytoplankton.Chlorophyta has 9 species of 8 genus,and accounted for 11.69%of the whole phytoplankton.Cyanophyta has 8 species of 7 genus,and accounted for 10.39%of the whole phytoplankton.Euglenophyta has 1 species of 1 genus.Bacillariophyta was the most,and Euglenophyta was the least.Harmful algae were identified.Harmful algae has 18 species of 13 genus,and belonged to 2 phylum.Bacillariophyta was the most and has 11 species of 9 genus in harmful algae.Pyrrophyta has 7 species of 4 genus in harmful algae.The abundance of Phytoplankton was 760.86 X 107 cell/m3 in the winter of 2016.The abundance of Phytoplankton was 98.15 × 107 cell/m3 in the summer of 2017.The abundance of Phytoplankton was 87.83 × 107/cell/m3 in the autumn of 2017.The abundance of Phytoplankton was 87.83 × 107 cell/m3 in the winter of 2017.The abundance of Phytoplankton gradually decreased from the winter of 2016 to the winter of 2017.27 speciesof zooplankton were identified in the Puqian bridge from the winter of 2016 to the winter of 2017.There were Protozoa,Rotifer,Cladocera,Copepods,Tunicata,Annelida,Mollusca and Pelagic larva.27 species belonged to 20 genus.Copepods was the main zooplankton.There were 11 species of 5 genus in Copepods,and accounted for 40.74%of the whole zooplankton.Protozoa was 5 species of 4 genus,and accounted for 18.65%.Both of Pelagic larva and Rotifer were 3 species of 3 genus,and accounted for 11.11%of the whole zooplankton respectively.Tunicate was 2 species of 1 genus,and accounted for 7.41%of the whole zooplankton.Mollusca,Annelida and Cladocera were 1 species of 1 genus,and accounted for 3.70%of the whole zooplankton respectively.The abundance of zooplankton was 196.08 × 103 ind./m3 in the winter of 2016.The abundance of zooplankton was 1895.2 × 103 ind./m3 in the summer of 2017.The abundance of zooplankton was 978.8 × 103 ind./m 3 in the autumn of 2017.The abundance of zooplankton was 87.2 × 1 03 ind./m3 in the winter of 2017.Water monitoring concluded COD,DO,DIN,DIP,non-iron ammonia,SS and so on.According to Redfield rate,water area of the Puqian bridge in Hainan belonged to water area of the poor nutritive salt.Water quality condition of investigation site fitted I seawater quality standard basically.Analyzed data of COD,DO,DIN,DIP,non-iron ammonia,SS and so on from different sites,it can be found DO,DIN and non-iron ammonia of inside the mangrove and nearby mangrove had significant difference.Mainly investigation object of nearby mangrove and outside the mangrove or inside mangrove and outside mangrove didn't have significant difference.So it can concluded building bridge didn't affect local ecosystem.In the meanwhile,compared to historical records,it can be found water quality condition gradually improved.Water quality situation from the heavy rich nutritive salt level transferred to the poor nutritive salt level.Few monitoring sites showed mild rich nutritive salt inside and outside mangrove.It deduced water change lead to growing of Cyclotella sp,because water change isn't frequently.All in all,local plankton composition construction is vulnerable,and water quality keep stable.Puqian bridge didn't affect local ecosystem at present.For make sure healthy and stable of local ecosystem,government take measure to solve this problems and get achievement.In present,building the Puqian bridge didn't show obvious effect for investigation sites and mangrove ecosystem.For ensure mangrove stable,it's necessary to continue investigation of plankton and water quality condition.These material will provide important reference for the same constructions so that effectively protect local ecosystem.