Distribution characteristics of phosphorus in sediments from different aquaculture areas in Yantan Reservoir,Guangxi

ObjectiveSediment phosphorus distribution characteristics and potential releasing in different types of aquaculture area in Yantan Reservoir,Guangxi were evaluated to provide reference for scientific development of aquacul-ture in the reservoir.MethodIn Yantan Reservoir,three stations from each following areas were selected:non-aquacul-ture area(T0),feeding cage aquaculture area(T1),ecological cage aquaculture area(T2)and fencing aquaculture area (T3). Surface sediment from 12 stations were collected in March(spring),June(summer),September(autumn)and De-cember(winter)of 2016,and standard measurements and testing(SMT)method was used to determinate contents of each form of phosphorus in phosphorus out of fresh water sediment.ResultPhosphorus content in surface sediment from dif-ferent aquaculture areas were different,the order of phosphorus contents was T1/T2>T3>T0.The sediment phosphorus content of T1 and T2 only varied in feeding seasons(summer and spring).The proportions of Fe/Al-P and Ca-P in sedi-ment from different aquaculture areas were obviously different,but the two were usually in inverse relation.The propor-tion of inorganic phosphorus(IP)was high,but the differences among various areas were insignificant(P>0.05).In T0, only proportion of Fe/Al-P had obvious seasonal difference;in T1,all phosphorus forms had obvious seasonal difference;in T2,proportion of Ca-P had no seasonal difference,but proportion of Fe/Al-P in winter was significantly higher than in other seasons(P<0.05);in T3,all forms of phosphorus excepted Ca-P had no seasonal difference.The correlation analy-sis between various phosphorus forms and total phosphorus(TP)showed that the correlation between IP and TP was the highest with correlation coefficient(R2)being 0.963,and the correlation between organic phosphorus(OP)and TP the lowest with correlation coefficient being 0.578.ConclusionAll aquaculture types can improve the phosphorus content and release potential in sediment in the reservoir,and ecological cage aquaculture can utmostly unleash the potential of phosphorus in winter.Operating aquaculture in reservoirs should carry out ecological aquaculture and alternate culture in different areas to avoid substrate environment worsening in partial waters due to nutrients accumulation.