The Research Of Oxyrrhis Marina Feeding On Three Species Of Marine Microalgae

Oxyrrhis Marina is a kind of marine planktonic eukaryotes,O. Marina can makediatoms, green algae, algae, dinoflagellates, chrysophytes, cyanobacteria, theunicellular red alga and bacteria as the main food for heterotrophic life.Cyanobiumsp.and Pleurochrysis dentata is the new recorded species of red tide algae in Hebeiprovince,Platymonas Subcordiformis is one of the main quality natural food of manyfish, shrimp, crabs, shellfish larvae and other economic animals.The purpose of thisstudy is to provide a theoretical basis for the biological control of red tide by studyingO. Marina feeding on Cyanobium sp. and Pleurochrysis dentate. The study of O.Marina feeding on Platymonas Subcordiformis provides the basis of prevention andcontrol of Oxyrrhis marina in the biological feed culture process.The experiment was divided into three parts.The first part is provided with threetemperature gradient:15℃,20℃,25℃, studying the growth of the three species ofmarine microalgae under different temperature when other conditions is consistent,providing the experimental data for the O. Marina feeding experiment. The secondpart is the study of O. Marina in the triangle bottle feeding on three species of marinemicroalgae, initial density setting of algae are the same, making O. Marina in threeconcentration gradient, each kind of microalgaes has three experimental groups andone control group, each group has three parallel. The Cyanobium sp. initial density is3.4×107cells/mL, O. Marina initial density are0.8×104cells/mL,2.4×103cells/mL and0.8×103cells/mL; P. Dentata initial density is6.6×105cells/mL, O.Marina initial cell density are3.9×103cells/mL,2.4×103cells/mL and1.7×103cells/mL; P. Subcordiformis initial density is5.60×105cells/mL, O. Marina initialcell density are0.65×104cells/mL,0.37×104cells/mL and0.11×104cells/mL.After inoculation with O. Marina, training cycle is15d, observing O. Marina feedingon three kinds of microalgae, the culture liquid color changes and the algae celldensity changes in the experimental process. The third part is that O. Marina feed onthree kinds of microalgae in the aquarium, the experiment setup of each microalgaeare respectively provided an experimental group and a control group. The microalgaesof experimental group vaccinate with O. Marina in exponential phase, Cyanobium sp.initial density is1.5×107cells/mL, O. Marina is1.4×103cells/mL; P. dentata initialdensity is2.9×105cells/mL, O. Marina is1.8×103cells/mL; P. Subcordiformisinitial density is3.09×105cells/mL, O. Marina density is0.6×103cells/mL, theculturing period is15d, observe the color change of culture liquid and count of thealgae density in the course of the experiment. The experimental results show that:(1) three kinds of temperature settings, suitabletemperature were Cyanobium sp., P. dentata and P. subcordiformis grown in:20℃,25℃and25℃;(2)O. Marina on marine microalgae feeding process of differentsize and system type: Cyanobium sp. filamentous, larger than the O. Marina celllongitudinal furrow length, O. Marina when feeding a segment of the wrapped into alongitudinal groove; P. dentata and P. subcordiformis were single individual cell, farless than the O. Marina cell size, O. Marina is gradually the whole feeding algae cellwrapped into a longitudinal groove, and then through the protoplasm creeping into thebody feeding. The experiment also found, two division in O. Marina containing P.subcordiformis;(3) with different degree of the algae liquid feeding, the color willchange, when the number of O. Marina density reached105cells/ml, medium colorpink; after inoculation with6h, the rate of ocean tip thunbergii feeding on Cyanobiumsp., P. dentata and P. subcordiformis was100%;(4)with the marine O. Marina initialcell density decreased, marine tail algae in the initial density of3.4×107cells/mLCyanobium sp. training time to reach the steady period needed solution increased,respectively, after inoculation with3d,4d and6d, Cyanobium sp. is feeding finishedthe time required is increased, respectively after inoculation, for5d,10d and15d; withthe O. Marina initial cell density decreased, marine tail algae in the initial density of6.6×105cells/mL P. dentata training time to reach the steady period needed solutionincreased, respectively, after inoculation with4d,5d and12d, the P. dentata is feedingafter the required time also increased after inoculation, respectively, for6d7d and13d;with the O. Marina initial cell density decreased, P. subcordiformis marine tail algaein the initial density of5.60×105cells/mL cultured in steady stage time increasing,after inoculation, respectively, for4d,5d and7d. P. subcordiformis were feedingfinished the time required is increased to9d10d and12d, after inoculation,respectively;(5) Algae and O. Marina density change trendtion are similar withtriangular bottle in the aquarium. The initial density ratio of O. Marina andCyanobium sp. is0.010%in the aquarium, between triangular bottle1group (0.022%)and group2(0.007%), the time of Cyanobium sp. are fed completly is5d; The initialdensity ratio of O. marina and P. dentata is0.600%,similar with the triangle bottle1group (0.600%),the time of P. dentata are fed completly is8d;The initial density ratioof O. marina and P. subcordiformis is0.200%, similar with the triangle bottle3group,the time of P. subcordiformis are fed completly is13d.In short, the processes of O. Marina feeding on different size and system of marinemicroalgae are different. Culture methods influente the color changing of medium.Microalgae species and the initial concentration of algae and O. Marina effect O.Marina’ feeding. The succession of Cyanobium sp. population, P. dentata populationsand P. subcordiformis population to O. Marina population are completed during the construction of15d.