Optimization Of Cultivating Conditions Of Skeletonema Costatum,and Its Application In The Culture Of Bioflocs

In recent years,industrial aquaculture,in China,developed unbalanced in various regions,although this highly level mechanized and intensive cultivation pattern has made some achievements,the problem of this pattern,such as equipment investment,operating costs was high and the technology not mature,are restricting its promotion.A low operating cost and environment-friendly aquaculture technology“biological floccules technology”developing rapidly,but the water quality control relies on high ecological preparations,the lack of feed nutritionand and poor stability mad it not porfect.We have studied on natural sea area,isolated culture of skeletonema costatum,to explore the optimal culture conditions and the frame of skeletonema costatum in the biological floccules to quickly build applications.In order to provide theoretical basis and reference data for biological floccules stability studies,fish bait fortified,stable water quality control.1 Dominant algae isolation and culture in biological flocculesNatural waters at low areas and aquaculture factory outlet connecting,the growth of algae,mostly with good environmental tolerance,good purification effect.There are amount of algae in sewage draining exit besideslow-lying place of natural waters and aquaculture factory.Most of them have good environmental tolerance and water purification effects.This experiment used the modified micro pipette separation process Separated of three possible application in the effects of biological floccules quickly form.Expansion population culture has been used on the there algae for the algae body physiological ecology in order to analysis application possibilities.The results show that,anabaena sp.and melosira sulcata are not suitable for application in the biological floccules technology,skeletonema costatum are suitable for application in the biological floccules.2 Skeletonema costatum in biological floccules culture under the condition of the optimal growth conditions of explorationThe effects of temperature(levels of 10,15,20,25,30,35?),salinity(levels of10,15,20,25,30,35)and sodium silicate density(levels of 0,2,5,10,15,20 mg/L)on growth of Skeletonema costatum and variation of chlorophyll-a content in culture water were studied with three single factor experiments performed under simulated biofloc culturing condition.The results indicated that the optimal growth temperature of the algae was 30?and it could also grow normally at 10?,the optimal salinity was 30,and the optimal sodium silicate density was 5mg/L.Under the condition of optimal temperature,salinity and sodium silicate density,the growth process was of typical S-shape growth curve of microalgae.Skeletonema costatum could not grow under high temperature(35?)and grew poorly at salinity lower than 25.The maximal density of algal cells rose with the increase of sodium silicate density of 0-5mg/L,and algae reproduction was restrained when the density was more than 10mg/L.Therefore,in aquaculture production,it was possible to increase the yield of Skeletonema costatum,reduce feed convertion ratio and farming cost by properly increasing the temperature,salinity and adding appropriate sodium silicate.Because Skeletonema costatum has the characteristics of growing well with high and low temperature and high salinity,and the morphological characters of long chain,branched chain and spiny surface could facilitate its participating in the development and formation of biofloc,thus the application of the algae in mariculture production will be one of the important research fields of ecological farming using biofloc in the future.3 The most moderate Skeletonema costatum adding amount of inquiry experiment in biological floccules algalWe has studied by single factor test,simulation frame of biological floccules culture under the condition of different algal(0,0.5,1,3,5×10~4 cells/mL)amount of total suspended solids in biological floccules,ammonium nitrogen and nitrate nitrogen in water.The results showed that the frame of algal the optimum adding amount of 1 or 3 x 10~4 cells/m L.Under the adding amount,the growth of algae in water body in good shape,suspended solid in 5-7 days have obvious advantages than other groups(P<0.05).Ammonium nitrogen and nitrate nitrogen in water are relatively low,but there was no significant advantage than the other two groups(P>0.05).4 The further researching of most moderate Skeletonema costatum added,,bacteria amount and C/N ratio in biological flocculesSimulation was studied through orthogonal experiment analysis in biological floccules technology training under the condition of different Skeletonema costatum added concentration(1,3,5×10~4 cells/mL),amount of beneficial bacteria added(0.1,0.5,10×10~5 cells/mL)different C/N ratio regulation(10:1,15:1,20:1)of the total suspended solids in water,find the best combination collocation.Repeated trials ammonium nitrogen determination in water,and the content of nitrate nitrogen,total suspended solids.Results show that,the C/N ratio regulation to choose collocation of all the sons of article ribs in 1×10~4 cells and the amount of algal added amount of beneficial bacteria added 1×10~5bacteria content combination effect is best.But its combination with C/N ratio regulation to choose those days in the frame of algae content in 2×10 ~4cells and bacteria amount 0.5×10~5 bacterial combinations,C/N ratio regulation to choose collocation of all the sons of article ribs in 3×10~4cells and the amount of algal added amount of beneficial bacteria added 0.1×10~5 bacteria amount two combination disparity is not obvious.Repeated trials in the best combination of quality regulation effect is good,total suspended solids content difference was not significant(P>0.05)...