The Lysis Rate Of Phytoplankton In Typical Areas Of Baiyangdian Lake And Aquatic Microcosm

"The Pearl of North China"-Baiyangdian Lake is the largest inland freshwaterlake in North China, which located in the mid-east region of Hebei Province, playedan important role in regulating surrounding environment such as temperature andwet conditions, climate, water supply, etc. In recent years, the eutrophication ofBaiyangdian aggravated, algal blooms occured frequently. Research on theoccurrence and development of algae provided a basis for blooms governance. Thealgae cell lysis rate in typical areas of Baiyangdian Lake (village area, clean waterarea, cultivation area) was studied, as well as its spatial and temporal variation andimpact factors. The occurrence and disappearance of algae were explored from theperspective of microecology, which provided valid data for the assess of watercondition of Baiyangdian Lake. Meanwhile, microcosm simulating watereutrophication process in natural environment was founded, esterase activity andalgal cell lysis rate were discussed under different nutrient concentrations. Theresults offered a foundation for the prevention of eutrophication and water bloom,provided enzyme theoretical basis in effectively controlling water bloom. The resultswere followed as:1The phytoplankton lysis rates in Baiyangdian Lake existed obvious temporaland spatial distribution. In temporal view, the lysis rate remained at highconcentration from May to July, minimized in September, then rised rapidly fromOctober to November. On the spatial side, the mean value of algal lysis rate in2013was: clean water area>village area>cultivation area.2The mean lysis rate under different concentration in microcosm in2013wasas followed: Group7> Group1> Group2> Group5> Group6> Group3> Group4.The algal lysis rate of oligotrophic group7reached maximum, with the eutrophicgroup5and6followed, while the rate of moderate nutrient group4was minimum.This result was similar to the spatial discrepancy of the phytoplankton lysis rate of Baiyangdian Lake.3Correlative analysis showed that PEA was significantly positively correlatedwith chlorophyll concentration（P<0.01）, which indicated that phytoplankton wasthe main source of esterase in Baiyangdian Lake, the estimation of algal lysis rate ofBaiyangdian Lake using esterase activity method is feasible. PEA was positivelycorrelated with water temperature （P<0.05）, which indicated that temperature hadan effect on phytoplankton growth. DEA was significantly positively correlated withAPA in water and sediment（P<0.01）, PEA was negatively correlated with APA inwater, which showed that DEA and the algal lysis rate in oligotrophic water washigher, while PEA in phytoplankton remained low. This verified the validity of thisstudy to some extent.