| Based on the environmental survey in July, October, 2013, the surface and bottom of water and sediments were sampling in Houtou Bay of Gouqi Island. Analysis the nutrition level of aquaculture by studying the nitrogen and phosphorus distribution at mussel different growth stages in mussel farm. Understand the contribution rate and causes of the sediment nutrient to water by studying nitrogen and phosphorous releasing from the sediment in the laboratory. To understand the culture area of carbon system, carbon distribution and stability are implemented in different growth stages of Mussels. Provide the basis for sustainable aquaculture and carbon sink fisheries aquaculture ecological evaluation system under the background of the establishment of. Establish culture ecological evaluation system to provide the basis under the background of sustainable mariculture and carbon sink fisheries by studying the ecological and the effect ecosystem carbon during the different mussel growth periods. The results are as follows:Spatial MDS clustering based on 9 parameters, including inorganic nitrogen,phosphate, dissolved inorganic carbon(DIC), dissolved organic carbon(DOC), particulate organic carbon(POC) in seawater and total nitrogen, total phosphorous, total carbon and total organic carbon in sediment. The results showed that: culture is divided into 4 groups during mussel maturation period, the culture center were divided in Q1, the culture peripheral were divided in Q2, the seaweed field were divided in Q3, the import and export were divided in Q4, and the culture is divided into 3 groups during mussel seeding period, the culture area were divided in q1, the seaweed field were divided in q3, the import and export were divided in q4.Analyse the mariculture nutrition level at two key stages of mussel growth by study the concentration and distribution of nitrogen and phosphorous in the culture area during mature and seeding stage of mussel. In the seawater scale, cultivation area is rich in nutrition and eutrophication during mussel maturation period. The concentration of nutrients in mussel farm was significantly higher than that in control sites(p<0.05), the nutrition levels showed a “high inside-low outside” pattern. The cultivation area is poor in nutrition and during mussel seeding period, and the concentration of nutrients in mussel farm was significantly lower than that in control sites(p<0.05). In the sediment scale, the total nitrogen and total phosphorus concentration in sediments of mussel farm is significantly higher than that in control sites(p<0.05). The sediment nutrient release experiment showed that: the release rate and release quantity of ammonium nitrogen is higher than other inorganic nutrients, and the sediment adsorbed the phosphorus constantly. The release rate and release quantity of ammonium nitrogen in mussel farm is significantly higher than that in control sites(p<0.05). Research shows that: the metabolism of mussel is fast under high temperature during mussel maturation period, mussel filter feeding discharge nitrogen and biodeposition accumulation in the sediment, the sediment under mussel farm is easy to release inorganic nitrogen. The nutrient emissions exceed the environmental load that lead to the water eutrophication in mussel farm during mussel maturation period. The metabolism of mussel spats under low temperature is lower than that during mussel maturation period. The nutrient of seawater of mussel farm that is emission by mussel and released by the sediment in rich nutrient is used rapidly by primary producers. The filter feeding and excretion of mussel spats accelerate the nutrient cycling and purify the sea water in culture areas.Understand the effect of mussel culture on the carbon distribution by researching the carbon pattern on two key periods of mussels. In the seawater scale, the dissolved inorganic carbon distribution on the surface shows “low insider-high outsider” pattern. The concentration of DIC in mussel farm was significantly lower than that in control sites(p<0.05). The distribution pattern of bicarbonate is in accord with DIC. Mussel absorbs a great deal of bicarbonate in seawater for growth and calcification, causing the decreased of carbon dioxide partial pressure in the surface seawater. The balance of carbonate pump was balance in the surface of mussel farm. The mussel rafts decreased the water exchange in the vertical what block the DIC from the deposition and mineralization of sediment. Carbon dioxide in the atmosphere continued to dissolve in the seawater and is detained by mussel. Mussel culture area has the carbon sink effect. The dissolved organic carbon distribution in the bottom shows “high insider- low outsider” pattern. The concentration of DOC in mussel farm was significantly higher than that in control sites(p<0.05). The level of organic nutrition and the concentration of inorganic nitrogen is higher in mussel farm than in the control sites. Sea water in high nutritional can be against DOC stability. In the sediment, the distribution of total nitrogen and total phosphorous shows “high insiderlow outsider” pattern. The concentration of TN, TP in mussel farm was significantly higher than that in control sites(p<0.05). Biodeposition accelerate the carbon deposition that is conducive to accumulation of carbon in the sediments. But the sediment which has rich nutrition and organic matter is not in favor of the stability of carbon, so the sediment carbon with rich nutrition is easy to release. Research shows that: there are large of carbon retaining in the mussel farm, but the stranded carbon instability.In summary, the nutrient can be restored in the mussel farm. The high conversion of mature enhanced the nutrition level, while low conversion of seeding accelerated nutrient cycling to reduce the nutrient levels. The carbon distribution pattern changed in mussel culture. Mussel farming has carbon sequestration effects. |
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