| Polyculture model of Ulva pertusa.Chlorella pyrenoidesa and Apostichopus japonicas were studied in Jintuo aquatic products co.Ltd.at Zhuanghe Jingchang village in Dalian from Jun 2014 to May 2015.It designed about U. pertusa, C. pyrenoidesa of polyculture model setting with A. japonicus as experimental group respectively, and the A. japonicus worked as control group. The research content including analysis of water physical and chemical factors, this paper discussed change of phytoplankton species composition, density, diversity and evenness. And then, the U. pertusa, C. pyrenoidesa and A. japonicus of interaction research was made in polyculture ecosystem at key Aquatic Biological laboratory of Dalian Ocean University in Liaoning province, set a high concentration of C. pyrenoidesa(109 cell/ L), low density C. pyrenoidesa(108 cell/ L) as the experimental group, U. pertusa, C. pyrenoidesa(108 cell/ L) as the control group and blank control group of seawater. This research includes the analysis of the experimental group of ammonia nitrogen, nitrate nitrogen, nitrite nitrogen and active phosphorus content changes, U. pertusa weight, A. japonicus weight and changes of C. pyrenoidesa density. It aims to explore the advantages of these polyculture models and interaction of them.Outdoor experimental results were as follows: ammonia nitrogen and nitrate nitrogen concentration in pond 8# in Jun and July of 2014 was significantly lower than the other two ponds, from August and later are relatively higher than other two ponds(P < 0.05), it could explain U. pertusa and C. pyrenoidesa made contribution to the absorption of ammonia nitrogen and nitrate nitrogen in water. It is not obvious difference between the remaining indicators groups of nitrogen and phosphorus, so it reveals that U. pertusa and C. pyrenoidesa made greater effective effected on the absorption of inorganic nitrogen than the absorption of organic nitrogen. 40 species of phytoplankton were detected in pond 8#,36 species in pond 9#,39 species in 9# experimental group,29 species in pond 10#,it was bacillariophyta of the dominant groups in phytoplankton composition, pyrrhophyta was secondary phytoplankton dominant species in pond 8# and pond 10#, chlorophyta was secondary phylum of pond 9#. Zooplankton are mainly copepods and protozoa. According to the correlation analysis, phytoplankton density of the four groups are mainly restricted by temperature and nitrogen, the nitrogen sensitivity in pond 8# was relatively in low level.Phytoplankton diversity of pond 8#, 9# and 9# experimental group are mainly in level 3 and 4,level 2 and 3 in pond 10#. Laboratory test results were as follows: C. pyrenoidesa had a significant inhibitory effect on U. pertusa, and high concentration(109 cell/L) was much more significanteffecttion. But meanwhile U. pertusa also had inhibition to C. pyrenoidesa as reaction, and high concentrations of C. pyrenoidesa has a more significant inhibitory effect. While it was obviously that U. pertusa promotes A. japonicus’ s growth.In conclusion, U. pertusa and A. japonicus mixed culture model can help promoting the growth of A. japonicus, controling the ammonia nitrogen and nitrate nitrogen content of water. At the same time, C. pyrenoidesa can restrain the growth and reproduction of U. pertusa when it grows too fast, to ensure the A. japonicus breeding is efficient and green. There were few comparisons between indoor and outdoor experiments for interaction of aquaculture species in the algae polyculture model in previous studies, so it was a great guiding significance from this study for the A. japonicus aquaculture production, and algal pattern research in the future. |
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