杂食性鱼类排泄物中藻类光能活性研究

借助叶绿素荧光技术,通过对杂食性鱼类鲫鱼(Crucian Carp)和金鲫鱼(Gold Crucian Carp)摄食微囊藻(Microcysis aeruginosa)后排泄物的培养,从鱼类排泄物藻类叶绿素荧光活性的角度探讨了杂食性鱼类在控藻上的应用.结果表明,鱼类摄食对微囊藻生长及叶绿素荧光参数均有显著影响(P<0.05).鲫鱼组的叶绿素荧光参数ΦPSII从第3d开始,Fv/Fo、Fv/Fm、ETR和qP从第5d开始随培养时间的延长而增加,而NPQ始终呈下降趋势.金鲫鱼组的叶绿素荧光参数(Fv/Fo、Fv/Fm、ΦPSII、ETR、qP)在培养期间一直呈降低趋势.鲫鱼组的Chl a浓度与细胞密度在培养期间先下降再上升,最后恢复至对照组水平,且Chl a浓度同部分叶绿素荧光参数(Fv/Fo、Fv/Fm、ΦPSII)呈现极显著正相关(P<0.01);金鲫鱼组的Chl a浓度与细胞密度于实验期间均下降,实验期间一直低于对照组,且两参数均与叶绿素荧光参数(Fv/Fo、Fv/Fm、ΦPSII、ETR、qP)呈极显著正相关(P<0.01).可见,微囊藻经鲫鱼摄食后,其叶绿素光合及生长活性经过短暂的下降后会逐渐恢复,而金鲫鱼可有效降低微囊藻活性,但金鲫鱼作为一种观赏鱼类,不适宜在大面积水体放养.

Changes in the photosynthetic activity of Microcystis colonies after gut passage through omnivorous fish

The photosynthetic activity of cyanobacteria (predominantly Microcystis spp.) after pass through the digestive tract of Crucian Carp and Gold Crucian Carp was determined by PAM fluorimeter(Dual-PAM-100) so as to argue if ingestion of cyanobacterial biomass by Crucian Carp and Gold Crucian Carp could be considered as one of the biological methods for the water bloom formation control. The results showed that fish digestion had a significantly effect (P<0.05) on the photosynthetic activity and growth of microcystis. The photosynthetic activity, Fv/Fo, Fv/Fm, ETR and qP, of phytoplankton from Crucian Carp guts after the fifth day and ΦPSII from the third day became significantly higher than that of phytoplankton from Gold Crucian Carp, while NPQ decreased during the incubation. The Fluorescence parameters, Fv/Fo, Fv/Fm, ΦPSII, ETR and qP, form goldfish passage, decreased sharply during the incubation. The Chlorophyll-a concentration and cell density of Microcystis from Crucian Carp gut passage decreased at the beginning, then increased, and finally restored to the level of the control. Moreover, Chlorophyll-a concentration had an extremely significant (P<0.01) positive correlation with the chlorophyll fluorescence parameters respectively. However, the Chlorophyll-a concentration and cell density of Microcystis from Gold Crucian Carp gut passage had a extremely significant (P<0.01) positive correlation with the chlorophyll fluorescence parameters, kept declining during the culture period and much lower than that of control, Finally, the Chlorophyll fluorescence and growth of Microcystis after Crucian Carp digestion droped at the beginning, and then restored gradually. But for Gold Crucian Carp, gut passage significantly damaged the photosynthetic activity of Microcystis. Since the Gold Crucian Carp was usually stocked as ornamental fishes, it isn’t suitable to be considered as cyanobacteria bloom control.