高温条件下营养盐对江蓠生长与氮、磷去除效率的影响

以两种大型红藻菊花江蓠和脆江蓠为试验材料,开展为期30d的养殖试验,通过分析江蓠的生长和氮、磷变化特征,研究在25℃条件下不同质量浓度氮(磷)营养盐——1.65(0.23)mg/L、4.12(0.57)mg/L、8.24(1.14)mg/L、12.35(1.71)mg/L、16.5(2.28)mg/L对江蓠生长和去除效率的影响。试验结果表明,整个试验周期各组菊花江蓠相对生长速率无显著性差异(P>0.05),分段研究发现,各组相对生长速率均有随时间的增加而下降的趋势;氮(磷)质量浓度超过8.24(1.14)mg/L各试验组的脆江蓠相对生长速率显著低于其他各组(P<0.05),且在养殖超过10d后,表现为负增长,并随着营养盐质量浓度的升高出现负增长加快的趋势。各试验组氮、磷去除效率均显著高于对照组(P<0.05),营养盐质量浓度相同的条件下,菊花江蓠对磷的去除效率显著高于脆江蓠(P<0.05);两种江蓠对水体中氮、磷的去除时段均主要集中在0～10d。营养盐质量浓度对两种江蓠的氮、磷吸收速率产生显著的影响,吸收速率随氮、磷质量浓度的升高而增大。研究结果表明,在25℃及氮(磷)质量浓度小于8.24(1.14)mg/L时,菊花江蓠对水体中的氮、磷营养盐有很好的去除效果,且能维持正常生长。

Effect of Nitrogen and Phosphorus Concentrations on Removal Efficiency of NO_3^--N and PO_43--P and Growth in Two Species of Seaweed Gracilaria at High Water Temperature

The sea weeds Gracilaria lichenoides and G.chouae were cultivated in N(P)concentration of 1.65(0.23)mg/L,4.12(0.57)mg/L,8.24(1.14)mg/L,12.35(1.71)mg/L,and 16.5(2.28)mg/L at water temperature of 25℃for 30 days to evaluate the effects of nutrient concentrations on removal efficiency of NO 3--N and PO 4 3--P and growth of the sea weeds.The results showed that there was no significant difference in relative growth rate(RGR)in the experimental group of G.lichenoides,the declined RGR of G.lichenoides with the cultivation elapse.The G.chouae had significantly lower RGR at N(P)concentration of over 8.24(1.14)mg/L than the sea weed in the other groups did,showing negative growth in more than 10 day culture.There was significantly higher removal efficiency of NO 3--N and PO 4 3--P in the test groups than that in the control group.Under the same nutrient concentration,G.lichenoides had significantly higher removal efficiency of PO 4 3--P than G.chouae did.The removal of N and P was primarily observed in the 0 to 10 days in the two species seaweed,and significantly affected by the N and P uptake of two species seaweed,the uptake rate being increased with the nutrient concentrations.The findings indicate that G.lichenoides is more efficient at remov of N and P at water temperature of 25℃at nutrient concentration of below 8.24(1.14)mg/L.