Study On ·OH Rapid Inactivation Of Typical Harmful Dinoflagellates

Red tide refers to the phenomenon that plankton in the ocean excessively proliferates or accumulates and discolors seawater.The frequent occurrence of red tides poses a serious threat to the marine ecological environment,social and economic development,and human health.Among them,the poisonous and harmful dinoflagellate red tide is the most serious.The study was based on a strong ionization discharge at atmospheric pressure to produce high cocentration·OH.Using the·OH experimental device to inactivate the Alexandrium catenella,Alexandrium minutum and Prorocentrum minimum.The dose-effect relationship and time-effect relationship of·OH inactivation on three kinds of dinoflagellates was investigated,and compared the effect of inactivation with CuSO4,C1O2 and H2O2,and studied the effect of·OH on the oxidation damage of DNA by DAPI fluorescence staining.(1)Using·OH kill Alexandrium catenella,Alexandrium minutum and Prorocentrum minimum,respectively.The results showed,the inactivation TRO dosages of ·OH for Alexandrium catenella,Alexandrium minutum and Prorocentrum minimum with density of 1.00×104 cells/mL were 0.91 mg/L,0.81 mg/L and 0.68 mg/L,respectively,the corresponding CT threshold values were 0.091 mg·min/L,0.081 mg·min/L and 0.068 mg·min/L.At the inactivation threshold,the chlorophyll fluorescence parameters Fv/Fm and Y(II)of the three dinoflagellates decreased to 0,and the algae could not perform photosynthesis.(2)CuSO4,ClO2 and H2O2 were used to inactivate Alexandrium catenella,Alexandrium minutum and Prorocentrum minimum,respectively,the results showed that:the CT threshold values of CuSO4 for inactivation Alexandra and Prorocentrum minimum were 5760 mg·min/L and 4320 mg·min/L,repectively,which were 50000 to 60000 times of·OH inactivation value;The CT threshold values of ClO2 for inactivation Alexandrium catenella,Alexandrium minutum and Prorocentrum minimum were 9.1 mg·min/L,8.1 mg·min/L and 6.8 mg·min/L,repectively,which were 100 times of·OH inactivation value;When the CT value of H2O2 for inactivation there kinds of dinoflagellates was 14400 mg·min/L,the inactivation rates of Alexandrium catenella,Alexandrium minutum and Prorocentrum minimum was only 45.2%,60.6%and 84.0%,respectivaly,indicating that H2O2 cannot totally inactivate these dinoflagellates.(3)DAPI fluorescence staining technique was used to study the DNA structure changes of different concentrations of·OH to kill three harmful dinoflagellates.The results showed that:the degree of DNA fragmentation increased with the increase of·OH concentration,·OH could cause irreparable damage to algae.In summary,the new advanced oxidation technology-based on a strong ionization discharge at atmospheric pressure to produce high concentration·OH can quickly and efficiently inactivate harmful dinoflagellates,and speculated the inactivation mechanism is mainly oxidative damage of DNA by·OH.