Research On Culture Character Of Chaetoceros Muelleri And Its Treatment In Shrimp Aquaculture Tail Water

Chaetoceros muelleri is a typical diatom which contain comprehensive nutrients,and it is widely used in shrimp,portunus crabs and oysters culture.Developing the treatment of aquaculture tail water can effectively reduce aquaculture pollution,and at the same time it can meet the demand of shrimp for living food during the aquaculture.In this paper,the morphology of Chaetoceros muelleri was studied by optical microscope,scanning electron microscope and freezing electron microscope.The fucoxanthin?Fx?in Chaetoceros muelleri was detected by ultra-high performance liquid chromatography?UPLC?and surface-enhanced Raman spectroscopy?SERS?.By optimizing the conditions of nitrogen,phosphorus,silicate nutrients and light intensity,the optimum conditions of growth and fucoxanthin accumulation of Chaetoceros muelleri were explored.By adding high concentration of nitrogen and phosphorus,the growth of Chaetoceros muelleri under high nitrogen and phosphorus conditions were studied and a kinetic model was constructed.The research are as follow.?1?The morphological study showed that the experimental strain was a typical Chaetoceros muelleri,fucoxanthin in Chaetoceros muelleri were detected by SERS and UPLC methods.?2?Nitrogen,phosphorus,silicate nutrients and illumination conditions were studied.It was found that Chaetoceros muelleri could grow well under the conditions of sodium nitrate 12.35 mg·L^-1,sodium dihydrogen phosphate 5.65 mg·L^-1,sodium silicate 2.97mg·L^-1 and illumination intensity 80 micromol·m^-2·s^-1.?3?Under the nitrogen and phosphorus deficiency condition,the growth of Chaetoceros muelleri is slow or decline,and fucoxanthin does not accumulate;excessive phosphorus will prolong the growth cycle of algae,inhibit the growth of algae and the accumulation of fucoxanthin;the growth and nitrogen and phosphorus consumption kinetics model of Chaetoceros muelleri under high nitrogen and phosphorus conditions was established,and the curve showed good agreement with the experimental data.?4?Conducted research on tailwater treatment in two plots,It was found that the tail water of Meihua?MH?plot increased with the dilution factor,and no significant difference?p>0.05?was found in the growth of cells.The biomass and fucoxanthin content were lower than F/2 group.The maximum removal rates of total nitrogen,nitrate nitrogen and ammonia nitrogen were 59.9%,58.2%and 52.5%,respectively.After one day culture,the maximum removal rates of total phosphorus and phosphate were 89.5%and 90.7%,respectively,and all were depleted on the eighth day?except F/2 group?;the tailwater of Yanyu?YY?was cultured with dilution factor.The increase of C.elegans cell growth did not find significant difference?p>0.05?,biomass and fucoxanthin gradually accumulated,and Chaetoceros muelleri grew well in undiluted YY tail water.