Studies On The Photosynthetic Activity Of Floating Algae In Shallow Water

With the intensification of China’s water eutrophication,algal blooms outbreaksfrequently.China’s economy has suffered a serious loss. The water bloom mechanism aswell as water bloom governance works currently focused on the impact of a single factorsuch as nutrients.However, the outbreak of water bloom is in a variety of factors(temperature, light, N/P).The possibility of water bloom is closely related tophotosynthetic algae production and growth.So investigation of algae photosyntheticactivity parameters in different water environment is of great value for the research ofwater bloom algae.PHTYO-PAM is an instrument that used for the study of algae growth,photosynthesis chlorophyll fluorescence dynamics. As a probe of photosynthesis,chlorophyll fluorescence has been used in extensive research. In this study, we determinedthe algae’s photosynthetic activity and water quality in the water body ofNandamenxi,Nandamenddong,Dongjiu,Qingnianyuan and Bahaolou from October31,2012to25December2012. We find that the cyanobacteria is of no photosynthetic activityin the water body of Nandamenxi and has a low photosynthetic activity in the water bodyof Nandamenddong. Changes of algae photosynthetic activity parameters are as follows.(1) Maximum of efficiency photosynthetic Fv/Fm The ranges of Cyanobacteria,Green algae and Diatoms/dinoflagellates in five water bodies are(0-0.8)(0-0.76)(0-0.76).Fv/Fm is highest in the water body of Dongjiu. There is no photosynthetic activity ofcyanobacteria in the water body of Nandamenxi.(2) Maximum rate of electron transport (ETRmax) Different algae in differentwater bodies changes a little and do not show significant trends. The ETRmax ofcyanobacteria is zero. The ranges of Cyanobacteria Green algae and Diatoms/dinoflagellates in five water bodies are （0-85.32）（0-213.6）and（15-183）respectively.(3) Rapid Light Curve (RLC) The RLC of cyanobacteria and Green algae is typical inthe five water bodies.The RLC of cyanobacteria is lowest in the water body ofNandamendong. The RLC of diatoms/dinoflagellates is different in different water body.(4) Chlorophyll a (Chl.a) Chlorophyll a (Chl.a) of Cyanobacteria is significant different in five water bodies and mainly in the water body of Dongjiu and Bahaolou.Overall, Chlorophyll a (Chl.a) has a downward trend in the five water bodies.Given that the dense duckweed covered the water body of Nandamendong, Wedesigned an experiment about duckweed: one sample is covered the entire surface of thewater body of Qingnianyuan and Nandamendong by duckweed, one is covered half ofsurface on the water body and another is of no duckweed. The conclusions are as follows:Photosynthetic activity is higher that of no duckweed in the water body of Qingnianyuanand is higher that covered the entire surface of the duckweed in the water body ofNandamendong.