| Rhopilema esculenta-Ruditapes philippinarum-Penaeus monodon Multi-nutrient-level coupling breeding pond is a new type of breeding model.In order to clarify its water quality,we selected the Rhopilema esculenta-Ruditapes philippinarum-Penaeus monodon ponds belonging to the liaoning daily agriculture group from June to September in 2016.We systematically studied the water chemistry,plankton and suspended particulates and their organic carbon stocks in four ponds.The main conclusions are as follows:1 Hydrochemistry and nutritional status of Multi-nutrient-level coupling breeding pond farming Rhopilema esculenta-Ruditapes philippinarum-Penaeus monodonThe changes of physicochemical factors were studied and the nutritional status was evaluated.The results showed:1)water temperature,pH and DO were relatively stable at(25.17±4.05)?,(7.88±0.33)and(7.10±1.62)mg/L respectively.Transparency and total hardness fluctuated a lot,showing(62.32±24.40)cm and(95.42±13.40)mmol/L;The result of alkalinity was(1.97±0.39)mmol/L,and it was relatively higher in the early stage of cultivation and gradually reduced in the middle and latter period.2)COD,TP and TN was calculated as(4.16±1.50)mg/L,(0.705±0.543)mg/L and(3.343±1.797)mg/L respectively.Howerver,inorganic nitrogen component was changeable,showing lower in the preceding period and higher during the latter period.Among them,Ammonia nitrogen accounted for 47.5%,Nitrate nitrogen 32.8%,Nitrite acid nitrogen 19.6%.DIP content(0.015±0.022mg/L)was low.3)This individual pond was eutrophicative.When it comes to the latter period of farming,ration of Nitrogen and phophorus are higher than 30 and it turned out to be Phosphorus limitation when DIP was not been detected.2 Species and biomass of planktonThe changes in species and quantity of plankton were tracked throughout the study period.The results showed:1)A total of 29 species of phytoplankton were detected during the whole breeding period,which attached to the pyrrhophyta,Chlorophyta,Euglenophyta,Cryptophyta,Bacillariopyhta,Chrysophyte,and Xanthophyta,and each of them accounting for 27.6%,24.1%?17.2%,13.8%,10.3%,3.4%,3.4%of the total species(genera).2)With the continuous development of aquaculture production,phytoplankton dominant species change.The dominant species belong to pyrrhophyta from June to July;While,from August to September,the dominant species belong to Euglenophyta.3)The biomass range of phytoplankton is(5.89-337.3)mg/L.Among them,the biomass of the pyrrhophyta is(2.14-206.76)mg/L,and the average is25.55 mg/L,accounting for 45.9%of the biomass.The biomass of the whole culture pond decreases first and then increases with the culture time.4)The three indicators of phytoplankton diversity index D,H',and J were 0.60?0.96 and 0.29 on average respectively.The diversity index H'and the homogeneity index J were both higher in June and August,while lower in July and September;the species richness index D was higher in June and September,while the other months were more stable and the numbers fluctuated in a tight range.5)A total of 14 species of zooplankton were detected during the whole breeding period.They are Sinocalanus tenellus,Paracalanus parvus,Acartia clausi,Cyclops strenuus,Cyclopsvicinus Uijianin,Sinodiaptomussarsi,Centropagestenuiremis,Harpacticoida,Microsetellanorvegica,Copepodite,Nauplius larva,Tintinnopsis wangi Nie,Tintinnopsis fluviatile Stein and Tintinnopsis conicus Chiang.6)There were significant fluctuations in the amount of plankton during the breeding period,with more at the early stage and less at the later stage,the overall mean value was(18500±494)10~7cell/ml.3 Structure of suspended particulates and organic carbon storage in Rhopilema esculenta-Ruditapes philippinarum-Penaeus monodon pondsThe study of suspended particulates and organic carbon storage in Rhopilema esculenta-Ruditapes philippinarum-Penaeus monodon ponds,with the goal of clarifying the characteristics of the ecological structure and function of polyculture ponds,as well as providing baseline data of the carbon cycle under different culture models to facilitate development of low-carbonfisheries.The results show that the total suspended particulates in the four experimental ponds were(41.71+4.08)mg/L.Among them,inorganic suspended particulates accounted for 72.2%of total suspended particulates;and organic suspended particulates account for 23.8%of total suspended particulates.In organic suspended particulates,humus and bacteria accounted for 17.9%of total suspended particulates.Phytoplankton dry weight 9.8%,zooplankton dry weight 0.1%.The mean concentration of total organic carbon(TOC)was(11.36±0.44)mg/L in the four experimental ponds.Among them,dissolved organic carbon accounts for 80.0%of total organic carbon,and granular organic carbon accounts for 20.0%of total organic carbon.The total suspended particulates in the experimental pool were relatively low.The inorganic suspended particulate matter is the main component.About 64.5%of the particulate matter.These results indicate that bacteria and detritus play a very important role in nutrient cycling and energy flow in this polyculture ecosystem. |
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