Study On The Spatial And Tmporal Differences Of Physicochemical Factors And Plankton In Film Shrimp Ponds

The experiment studied the changes of physical and chemical factors of water withspace and breeding phases, the species composition, quantity variance, distribution andvertical migration of plankton in the water of film-mulching shrimp ponds, aiming toprovide reference for healthy breeding of shrimps at high density in ponds of that kind.The results showed that the average of water temperature was29.8℃,salinity was9.5,pH was7.7,suspended solids was92.18mg/L,phosphate was0.369mg/L,nitritenitrogen was0.393mg/L,nitrite was0.775mg/L,ammonia was0.525mg/L,N/P was5.56,COD was24.65mg/L,DO was5.03mg/L;The range of water temperature from28℃to31.5℃, salinity from6.8to13.0,pH from6.9to8.7, suspended solids from22.33mg/Lto156.7mg/L, phosphate from0.017mg/L to1.248mg/L,nitrite nitrogen0.007mg/L to1.484mg/L,nitrite from0.004mg/L to3.140mg/L,ammonia from0.110mg/L to2.407mg/L,N/P from1.15to17.92,COD4.85mg/L to52.59mg/L,DO from2.74mg/L to9.36mg/L;In vertical direction, in each layer, phosphate, nitrate nitrogen, nitrite and sulphuret,ammonia nitrogen concentration were not significant (p>0.05),but COD were significant(p<0.05), the water concentration were W5>W4>W3>W2>W1, dissolved oxygen weresignificant (p<0.05), the concentration were W1>W2>W3>W4>W5;in the horizontaldirection, the indexes were significant (p<0.05) and phosphate, nitrate nitrogen, nitritenitrogen, ammonia nitrogen concentration had a similar distribution status were C>D>B>Ain each area, COD were D>C>A>B, DO were A>B>C>D.In the breeding process,There were46species of phytoplankton were identified,which belonged to8phyla, among which were Chlorophyta15species, Bacillariophyta9species and Cyanophyta9species, Cryptophyta2species, Euglenophyta2species,Xanthophyta3species, Pyrrophyta2species,Chrysophyta4species. Dominant speciesascribing to Chlorophyta and Bacillariophyta in early breeding,but in the mid and latebreeding were Cyanophyta and Chlorophyta, phytoplankton species were spiraled as thebreeding time and reach peak in mid-breeding.The range of species of phytoplankton from10to20, The mean was14,but the totalquantity of phytoplankton was low in theearly-breeding,high in the mid-breeding and low in the late-breeding, ranged from3.01×10~7cell/L to14.5×10~7cell/L,the average abundance of phytoplankton was8.60×10~7cell/L.There are28species of zooplankton were identified, which belonged to4generas,among which were Protozoa16species,Rotatoria8species,Copepoda2species and otherplanktonic larvae2species.Dominant species ascribing to Protozoa,Rotatoria,Copepoda inearly breeding;but in the mid and late breeding were Protozoa,Rotatoria.The species anddensity of zooplankton were extended as the breeding time,which reach maximum in thelate breeding, The density of the zooplankton were0.49×10~3~10.4×10~3ind/L,the range ofspecies were from4to16,waverage species,density was8species,3.46×10~3ind/L respectively.In vertical direction,the distribution of phytoplankton and zooplankton wasnot significant (p>0.05); But in horizontal direction, the regional distribution ofphytoplankton and zooplankton was significant (p<0.05), and the size of the total numberof which for the region were D>C>B>A. The Shannon-Wieaver index and Simpson indexof Plankton were lower throughout the whole period: phytoplankton were1.69~1.76,0.36~0.44, zooplankton were1.39~1.46,0.30~0.34respectively.The dominant species of phytoplankton were diefferent in different breeding periods:the early (Lobomonas sinensis), the mid (Chlorella vulgaris, Oscillatoria tenuis) and thelate (Platymonas subcordiformis, Microcystis incerta, Tribonema ulothrichoides), thequantity distribution and diurnal vertical change of phytoplankton in shrimp ponds: Thetotal number of phytoplankton in C were greater than B and A. Within24h day and night,in the early breeding the total number of phytoplankto,Lobomonas sinensis was less in12:00noon and more in0:00; In the mid breeding the total number of phytoplankton,Chlorella vulgaris, Oscillatoria tenuis was more in12:00and less in0:00; In the latebreeding the number of Microcystis incerta was more in12:00and less in6:00, but thetotal number of phytoplankton, Platymonas subcordiformis,Tribonema ulothrichoides wasnot change significantly.Lobomonas sinensis,Chlorella vulgaris,Oscillatoriatenuis,Tribonema ulothrichoides were floating during the day and sinking in thenight;Platymonas subcordiformis were sinking at noon and midnight but floating in theevening and dawn; Microcystis incerta were gathered in the middle water from themorning to the noon, sinking in the evening, floating in midnight. The dominant species ofzooplankton in different breeding periods:the early (Cyclops vicinus), the mid (Brachionusurceus) and late(Brachionus plicatilis,Vorticella campanula); The total number ofzooplankton in C were greater than B and A. Within24h day and night, in the earlybreeding the total number of zooplankton,Cyclops vicinus was less in12:00and most in18:00; In the middle breeding the total number of zooplankton,Brachionus urceus was notchange; In the late breeding the number of zooplankton,Vorticella campanula was less in6:00and most in12:00, but Brachionus plicatilis was not change. Cyclops vicinus weresinking in dawn,floating at noon, and began to sinking after midnight; Brachionus urceushad no obvious migration patterns; Brachionus plicatilis,Vorticella campanula weresinking during the day and floating in the night.