Experimental Measurement Of Primary Productivity Of Phytoplankton Based On Fluorescence Kinetic Parameters

As the main primary producer,phytoplankton is the basic link of the material circulation and energy flow of the ecosystem.The measurement of traditional primary productivity includes plant growth analysis and gas exchange method,which requires pretreatment of samples and is arduous,time-consuming and cannot be measured quickly and in real time.Chlorophyll fluorescence method and remote sensing method were used to obtain primary productivity with chlorophyll concentration and assimilation coefficient,which the result is a large deviation.Therefore,it is of great significance to realize the rapid and accurate measurement of the primary productivity of phytoplankton for the scientific research of Marine ecological environment,the verification of remote sensing ground data and understanding the evolution of global carbon cycle.The fluorescence kinetics method is mainly used for the analysis of photosynthetic parameters,and the photosynthetic process is based on the photoinduced variable chlorophyll fluorescence.Based on fluorescence kinetic parameters and cell energy flow,a rapid measurement method for the primary productivity of phytoplankton was studied by photosynthetic electron transfer rate.The main research work completed is as follows:(1)The characteristics of different kinds of microalgae were analyzed and the experimental methods were selected.Experimental comparison and analysis of green algae,cyanobacteria,diatoms and dinoflagellates door of 10 kinds of algae growth characteristics,biological activity and stress characteristics,the results showed that the activity of C.pyrenoidosa was good,the stress threshold was large and ambient light irradiated algal cells were evenly distributed,which was easy to be compared and analyzed.In this experiment,we chose the C.pyrenoidosa as the research object.Experiments for ease of chlorophyll a concentration data records in a row,to study the nuclear chlorella protein absorbance at 680 nm(OD680)correlated with the concentration of chlorophyll a,the results show that OD680 and chlorophyll a linear correlation coefficient in 0.996 above,and the measuring process is simple,suitable for continuous measurement,identified by OD680 absorbance value instead of chlorophyll a concentration data recording method.(2)The method of measurement of phytoplankton concentration of functional reaction centers was studied.According to the physical meaning of the parameters of the kinetic curve of fluorescence and combined with the theory of phytoplankton flow,the relationship of fluorescence,heat dissipation and optical chemical reaction is studied.So,the effective concentration analysis method in photosynthetic reaction is established.The results of the concentration measurement in the effective photosynthetic reaction of small globular algae in different physiological states were studied.and the results showed that:In normal physiological state,the results of the analysis of fluorescence kinetics parameters method and assimilation coefficient method were good,and the correlation coefficient was 0.999;Abnormal physiological condition,when compared with assimilation coefficient method,fluorescence kinetics parameter method is more accurate to reflects the phytoplankton photosynthetic activity(Fv/Fm),photosynthetic unit sizes(nPS?,),which caused concentration of functional reaction centers change.(3)The primary productivity characterization method of phytoplankton based on photosynthetic electron transfer rate was studied.Based on the effective photosynthetic reaction center concentration and photosynthetic electron transport"biooptical" measurement model,the photosynthetic electron transfer rate was calculated and the primary productivity was measured.C.pyrenoidosa as the research object,and oxygen rate PO2 as experimental comparison,through the photosynthetic activity inhibition test and algae growth inhibition test compared two methods of measuring results,the validity of the electron transfer rate measuremen t is verified.The results show that under different concentration of DCMU stress,phytoplankton Pe and PO2 has the very good consistency,and both decreased significantly with the stress concentration,PO2 and Pe was reduced by 71.550%and 68.870%respectively,the correlation coefficient is 0.934;The phytoplankton Pe and PO2 still had good consistency,and the correlation coefficient was above 0.955.Thesis research results show that:based on the analysis of the primary production of phytoplankton fluorescence kinetics parameters of has the characteristics of rapid,accurate,and no sample pretreatment,and realized the real-time analysis of the primary production of phytoplankton,For the development of the primary production of phytoplankton online,fast and exact directly measuring instrument in situ/scene provides the basis.