Effect Of Ipomoea Aquatica Floating-bed On The Zooplankton Community Structure In Intensive Fish Pond

In recent years, the Ipomoea aquatica floating-bed was introduced to aquaculture to purify the quality of aquaculture water and improve efficiency. We have studied the effect of the Ipomoea aquatica floating-bed on the zooplankton community structure in the grass carp pond from June to October2011, aimed at providing basic information of using Ipomoea aquatica floating-bed in intensive pond. The main results are as follows:(1) During the experiment,30kinds of protozoa were detected, including8species of Sarcodina and21species of Ciliata and1species of Suctoria.21kinds of protozoa were appeared in none-floating-bed ponds and30kinds of were appeared in floating-bed ponds. During the experiment, the density ((0.206±0.070)×105ind/L) of floating bed pond protozoa was significantly lower than non-floating-bed pond ((0.272±0.060)×105ind/L). The biomass of the floating-bed pond protozoa (0.19±0.06mg/L) and non-floating-bed Pond (0.18±0.12mg/L) was not significant different. The results showed that the Ipomoea aquatica floating-bed could promote the number of protozoan species significantly, and improve the protozoan diversity.(2) During the experiment, it was detected in rotifers38species belonging to7families,14genera, including36species in the floating-bed ponds rotifers, and28species in non-floating-bed ponds. Dominant species of the two types of ponds were essentially similar, including Brachionus calyciflorus, Brachionus diversicornis, Anuraeopsis fissa, Trichocerca pusila and Polyarthra dolichoptera. The density of rotifer was1892ind/L in the floating-bed pond and2255ind/L in the non-floating-bed pond, which was significantly different. The biomass of rotifer was1.30mg/L in the floating-bed pond and1.20mg/L in the non-floating-bed, which was not significantly different. The results showed that the Ipomoea aquatica floating-bed could promote the number of rotifer species significantly, improve the rotifer diversity and evenness, and inhibit the rotifers miniaturization effectively. (3) During the experiment, Four kinds of cladocerans and copepods were appeared, including Diaphanosoma leuchtenbergianum, Moina macrocopa, Cyclops and Sinocalanus. The species of cladocerans and copepods in different type of ponds has no difference. The density of cladocerans and copepods in the floating-bed pond (3.40±2.68ind/L) was lower than the non-floating-bed pond (6.06±4.23ind/L) not significantly different. The biomass of Cladocera and Copepods was no significant difference between floating-bed pond (0.065±0.053mg/L) and none-floating-bed pond (0.106±0.063mg/L).(4) There were no significant differences in the floating-bed pond area (the open water areas, the coverage area) among density and biomass of rotifers, protozoa, cladocerans and copepods.In summary, that the application of Ipomoea aquatica floating-bed in intensive pond can improve the diversity of rotifers and protozoa, stable water quality and have no effect to the biomass of zooplankton.