Laboratory Experiments Of Ecological Pilyculture Of Pinctada Martensii And Monostroma Mitidum

Three contents of this thesis were researched under laboratory conditions,which contained the excretion rates of N and P, oxygen consumption by Pinctada martensii,and the uptake rates of N and P, oxygen produce by Monostroma nitidum under different temperature,light,salinity,pH. Optimal polyculture biomass proration of P. martensii and M. nitidum. The effects of M. nitidum on the growth of the three microalgae(Tetraselmis Chui,Chlorella,Chaetoceros sp). The results showed that:1 The oxygen produce and the uptake of N and P in P. martensii aquaculture wastewater by M. nitidum under different ecological conditions.(1)In the 10～30℃temperature range, the excretion rates of NH₄⁺-N by P. martensii was the lagest, following was NO₃^--N. The oxygen consumption by P. martensii in the 10～30℃temperature range did not change much. The uptake of NH₄⁺-N and NO₃^--N by M. nitidum were more, and had a peak with increasing of tempeture, the peak appeared at 20℃,15℃respectively. The uptake of N and P by M. nitidum was strong in the 10～20℃temperature range. The oxygen produce by M. nitidum in the 10～30℃temperature range did not change much.(2)In the 0～8000 lx light intensity range,the excretion rates of NH4-N by P. martensii were the lagest, following was NO₃^--N. The maximum of the oxygen consumption by P. martensii appeared at 2000 lx. Under different light intensity, the uptake of NH₄⁺-N and NO₃^--N by M. nitidum were more. The uptake rates of NH₄⁺-N,NO₃^--N and PO43--P by M. nitidum had a peak respectively, the maximum appeared at 500 lx,4000 lx,4000 lx respectively. The oxygen produce by M. nitidum in the 0～8000 lx light intensity range continued rising.(3)In the 22～38 salinity range, the excretion rates of NO₃^--N by P. martensii were the lagest, following was NH₄⁺-N. The excretion rates of N and P by P. martensii had a peak respectively,the excretion rate of NH4--N and PO43--P reached the maximum at 26 of salinity,following at 30. The excretion rates of NO₃^--N and NO2--N reached the maximum at 30, following at 34. The oxygen consumption by P. martensii in the experimental salinity range did not change much. In the 22～38 salinity range, the uptake rates of NO₃^--N by M. nitidum were the lagest, following was NH₄⁺-N. The uptake rate of NH₄⁺-N reached the maximum at 30, following at 26, the uptake rate of NO₃^--N reaching the maximum at 26, following at 30 and 34, the uptake rates were identical. The oxygen produce by M. nitidum reached the maximum at 30 with increasing salinity.(4)In the 7.0～9.5 pH value range,the excretion of NH₄⁺-N and NO₃^--N by P. martensii were more. The excretion rates of N and P by P. martensii all reached the maximum at 8.0. The oxygen consumption by P. martensii at 8.5 reached the maximum. Under different pH value, the uptake of NH₄⁺-N and NO₃^--N by M. nitidum were more. The uptake rate of NH₄⁺-N reached the maximum at 8.0 ,following at 7.5. The uptake rate of NO₃^--N reached the maximum at 7.5, following at 8.0. The oxygen evolution by M. nitidum reached the maximum at 8.0, following at 8.5 with increasing pH value.2 Optimal polyculture biomass proration of P. martensii and M. nitidum(1)Growth rate(%) of P. martensii in the third culture pattern was lagest, it was 4.2, following was 3.91 in the second culture pattern, and 1.73 in the fourth culture pattern. Growth rate(%) of M. nitidum in the third polyculture pattern was lagest, it was 24.96, following was 21.91 in the fourth culture pattern, and 18.34 in the second culture pattern. Growth rate(%) of P. martensii in the first culture pattern was 1.79,and growth rate(%) of M. nitidum in the fifth culture pattern was 10.10.(2)The nutrient level in the first culture pattern was much higher than the other polyculture pattern. The concentration of N and P in all polyculture pattern was always increasing. The nutrient content of aquaculture water tended to increase with the biomass of M. nitidum reducing.(3)Comparing the overall average of COD in the culture patterns:the first culture pattern>the fourth culture pattern>the third culture pattern>the second culture pattern>the fifth culture pattern. The overall average of BOD in the culture patternsthe first culture pattern>the fourth culture pattern>the third culture pattern = the second culture pattern>the fifth culture pattern.(4)Comparing the overall average of N/P value in the culture patterns: the value of N/P was lagest in the second culture pattern, it was 15.55, following was 13.70 in the fourth culture pattern, 12.21 in the fifth culture pattern, 11.93 in the third culture pattern, 10.23 was minimal in the first culture pattern.(5)Culture results were better when polyculture biomass ratio of P. martensii and M. nitidum was 1:1. 3 The effects of M. nitidum on the growth of the three microalgae (1)When co-culturing with T. chui, daily special growth rate(%) of M. nitidum continued to decrease with the increasing of biomass of M. nitidum. The maximum growth rate was 4.14, when the biomass of M. nitidum was 1 g/L. The minimum rate was 0.53, when the biomass of M. nitidum was 20 g/L. When co-culturing with Chlorella,daily special growth rate(%) of M. nitidum was lagest when the biomass of M. nitidum was 2 g/L, the maximum was 5.36. The minimum rate was 0.51,when the biomass of M. nitidum was 20 g/L. When co-culturing with Chaetoceros sp, daily special growth rate(%) of M. nitidum continued to decrease with the increasing of biomass of M. nitidum. The maximum growth rate was 2.96, when the biomass of M. nitidum was 1 g/L. The minimum rate was 0.41, when the biomass of M. nitidum was 20 g/L.(2)The results clearly showed M. nitidum had inhibitory effects on the growth of the three microalgae. The inhibitory effects inhanced with the increasing of biomass of M. nitidum. Microalgae of co-culture group without logarithmic growth quickly entered the declining phase compared with the control group.