微绿球藻、隐藻、颤藻的种间竞争关系

Interspecific competition among Nannochloropsis sp.,Cryptomonas erosa and Oscillatoria sp.

采用陈海水配制的无机培养液,添加营养盐的无机培养液和对虾养殖池水3种培养液,分别对微绿球藻(Nannochloropsis oculata)、隐藻(Cryptomonas erosa)和颤藻(Oscillatoria sp.)进行单培养和混合培养,探讨3种微藻的增殖规律和相互关系。观测各处理组微藻的生长状况,并以Lotka-Volterra的双种竞争模型为基础,计算3种微藻在生长拐点后各取样点的竞争抑制参数。结果显示,在各处理组中,实验前期微绿球藻和隐藻对颤藻的生长都具有一定的促进作用,颤藻在混合培养组中的生物量大于单培养组,而微绿球藻和隐藻的最大生物量均出现在其单培养组。在各组生长拐点后,微绿球藻对颤藻的影响较小,隐藻对颤藻的抑制作用明显,各取样点隐藻对颤藻的竞争参数远大于微绿球藻对颤藻的竞争参数(P<0.05);颤藻对微绿球藻有较小的抑制作用,而对隐藻的抑制作用明显,各取样点颤藻对隐藻的竞争参数均为各组的最大值。实验结果表明,3种微藻按竞争力从大到小依次为颤藻,隐藻,微绿球藻。颤藻对隐藻和微绿球藻有较强的抑制作用,而微绿球藻和隐藻之间的竞争抑制作用较弱,能够达到"共存"状态。

Nannochloropsis oculata,Cryptomonas erosa and Oscillatoria sp. have been cultured in culture solutions which are inorganic aging seawater, aging seawater supplemented with nitrogen and phosphor and the effluent water of shrimp pond. Their multiplication rhythms and interrelationship are studied in single and mixed culture. Competition parameters of three microalgae are calculated with the Lotka-Volterra mode. The results show that in each groups, Nannochloropsis sp. and C. erosa can promote the growth of Oscillatoria sp. during the initial stages. Compared with the single culture groups, the biomass of Oscillatoria sp. was larger in mixed culture groups. However, that of N. oculata and C. erosa were the highest in single culture group. After the reflection point, N. oculata had little effect on Oscillatoria sp., and C. erosa inhibited the growth of Oscillatoria sp. obviously. The competitive parameters of C. erosa to Oscillatoria sp. is much higher than that of N. oculata to Oscillatoria sp. at each corresponding time （P〈0.05）. Oscillatoria sp. has little inhibitory effect on N. oculata, while it has significant inhibitory effect on C. erosa, and their competitive parameters to C. erosa are all the maximum value among all the treatment groups at each corresponding time. It is indicated that the competitiveness of these microalgaes from high to low are Oscillatoria sp., C. erosa and N. oculata; Oscillatoria sp. has significant influence on N. oculata and C. erosa; N. oculta and C. erosa have little inhibitory effect on each other, so they can coexist. [Journal of Fishery Sciences of China, 2009,16 （5）： 765-772]