Research On The Growth And Competition Of Peridinium Umbonatum Var.Inaequale And Microcystis Aeruginosa By Utilizing Organic Phosphorus

Organic phosphorus is one of the most important forms of phosphorus in nature.Many dinoflagellates and cyanobacteria have the ability to utilize organic phosphorus.The blooms that occur throughout the world include both cyanobacterial blooms and dinoflagellate blooms.The occurrence of algae bloom was bound to experience interspecies competition and community succession of phytoplankton.In order to explore the different types of organie phosphorus effects on the growth and interspecies competition between dinoflagellates and cyanobacteria,this paper used 54 kinds of organic phosphorus to study the growth of Peridinium umbonatum var.inaequale and Microcystis aeruginosa in different types of organie phosphorus;then selected the nucleotide organic phosphorus that can be utilized by both species of algae,set different initial biomass ratios of Peridinium umbonatum var.inaequale and Microcystis aeruginosa to co-culture the algae,observed their interspecies competition results,and explored the possible mechanisms of the utilization of organic phosphorus by these two algae from the activity and distribution of alkaline phosphatase;finally,taken the water samples from the thirty-Six-Foot Lake and Jiangdong District of Jiulongjiang River as the research object,and conducted simulation experiments to investigate the interspecies competition and community succession of phytoplankton under the control of organic phosphorus.The results of this study indicate that both Peridinium umbonatum var.inaequale and Microcystis aeruginosa could utilize organic phosphorus to maintain growth.In the mono-culture at 15?,there were 35 kinds and 25 kinds of organic phosphorus that could be utilized by Peridinium umbonatum var.inaequale and Microcystis aeruginosa,respectively.These two kinds of phytoplankton could make good use of nucleotides(5'-AMP,5'-CMP,etc.),amino acids(O-Phospho-D-Serine,O-Phospho-L-Serine,etc.),phosphoglycerol(p-Glycerol Phosphate,D-2-Phospho-Glyceric Acid,etc.),phosphonates(Phosphono Acetic Acid,etc.)and saccharide derivatives(inositol hexaphosphate,D-Glucosamine-6-Phosphate,etc.).Compared to Microcystis aeruginosa,Peridinium umbonatum var.inaequale could also make good use of dithiophosphate and phosphoenolpyruvate.In the co-culture experiment at 15?,Peridinium umbonatum var.inaequale and Microcystis aeruginosa could utilize 31 kinds and 14 kinds of organic phosphates,respectively.In terms of the utilization of nucleotides(5'-AMP,5'-CMP,etc.)and amino acids(O-Phospho-D-Serine?O-Phospho-L-Serine,etc),Peridinium umbonatum var.inaequale was more competitive than Microcystis aeruginosa.Under 15? culture conditions,regardless of the initial biomass ratio of Peridinium umbonatum var.inaequale and Microcystis aeruginosa(1:1,1:2 or 2:1),when cytidine monophosphate(5'-CMP)was used as the organic phosphorus source,Peridinium umbonatum var.inaequale would gain competitive advantage;however,when inorganic phosphate(K2HPO4)was used as the phosphorus source,Microcystis aeruginosa would gain a competitive advantage.From the alkaline phosphatase activity and distribution,it was assumed that Peridinium umbonatum var.inaequale,alkaline phosphatase was utilized to hydrolyze organic phosphorus and then reabsorbed;however,the mechanism of Microcystis aeruginosa utilizing cytidine monophosphate(5'-CMP)remains to be further explored.This paper taken the water samples of the Thirty-Six-Foot Lake and Jiangdong District of Jiulongjiang River as the research object.The primary phytoplankton in the surface water samples of the Thirty-Six-Foot Lake were maiuly dominated by chlorophyta(48.23%)and bacillariophyta(24.81%);the initial phytoplankton in the surface water samples of Jiangdong District of Jiulongjiang River were dominated by dino:flagellates(33.26%)and cryptophyta(37.42%)dominated.In the Thirty-Six-Foot Lake water sample,when the initial biomass of peridinium:microcystis was 4:1 and 1:1,the succession of phytoplankton communities in the organic phosphorus group was dominated by dinoflagellates(50.17%-50.19%)and Chlorophyta(29.96%-33.66%),and the dinoflagellates had obvious advantages in competition.Inorganic phosphorus group has relatively balanced growth of phytoplankton.When the initial biomass of peridinium:microcystis was 1:7,whether the organic phosphorus(5'-dAMP)or inorganic phosphorus(K2HPO4)as the source of phosphorus,microcystis aeruginosa all showed a clear competitive advantage.In the Jiangdong District of Jiulong River water sample,when the initial biomass of peridinium:microcystis was 36:1 and 2:1,the succession of phytoplankton communities in the orgahic phosphorus group was dominated by dinoflagellates(40.86%-48.47%),bacillariophyta(21.03%-33.89%)and chlorophyta(15.78%-17.88%),dinoflagellates became one of the dominant algae;bacillariophyta and chlorophyta proliferated significantly in inorganic phosphorus group.This study has deepened the theory of ecological nutrient metabolism and has important practical significance for the prevention and control of algae blooms in eutrophic water bodies.