| Limnology is a discipline of ecological,which mainly studies including the physical,chemical,and biological phenomena in inland waters.The reservoir is artificial water formed.When the reservoir is begain to work,the characteristics about the limnology are developed.When many exposed land along the river is flooded,the organic matter contained enters the reservoir and changes the water characteristic.It is main issues about the change of water environment,temporal and spatial changes of nutrients and eutrophication levels for scholars.In this study,to reveal the spatial and temporal characteristics of water environment factors and nitrogen and phosphorus nutrients,samples are conducted during 2012-2016 in Baihuahu Reservoir.The research results are as follows:?1?There are significant seasonal differences in the water environment conditions in Baihuahu reservoir.The average temperature of water is 17.27°C.The seasonal variation of water temperature is obviously.The water temperature is high in summer,and is low in winter.The pH mean value is 7.98 that reveal water is weakly alkaline.The multi-year average value of DO is 8.14 mg/L.The seasonal difference is obviously,the DO content is high in spring,and is low in autumn.The average value of SD is 1.62 m.Due to SD is the highest in spring,it is significant seasonal difference.The average value of Chlorophyll a is 10.38 mg/m3.Its maximum has reached in July 2014.The average value of CODMn is 2.53mg/L,and the seasonal variation is obvious.The concentration of CODMn is higher in summer and lower in winter.The spatial distribution of water temperature and pH is not obvious.The SD spatial distribution shows a trend of decreasing from the front of the dam to the tail of the reservoir.The spatial distribution of DO,Chlorophyll a is similar to CODMn,and it tends to decrease from the end of the reservoir to the front of the dam.?2?The concentration of NH4+-N ranged from 0.02 to 0.80 mg/L with a mean value of 0.17 mg/L in 2012-2016.It trend is decreasing.The concentration of TN ranged from 1.06 to 3.36 mg/L with a mean of 2.15 mg/L.the TN concentration showed a downward trend.The concentration of TP ranged from 0.02-0.10 mg/L with a mean value of 0.05 mg/L.It trend was decreasing.NH4+-N,TN,and TP are consistent in spatial variation,showing the spatial distribution of the tail of the library gradually decreasing toward the dam.In seasonal changes,NH4+-N and TN have the highest levels in spring and summer.TP has the highest spring content,followed by winter and summer,and the lowest in autumn.?3?Through the comprehensive nutrition index method,the TSI???value ranged from 42.95 to 6.73,with an average of 50.41.The overall performance is medium nutrition-mild eutrophication.It is mainly mildly eutrophicated before in 2014.After year in 2014,the nutrition is dominant and the nutritional level is decreasing.The spatial distribution of TLI???increases from the front of the dam to the tail of the reservoir.Huaqiao,Maixihekou and Yanuzhai have higher value of TLI???,which are prone to eutrophication.In terms of seasonal changes,the TLI???is the highest in summer,followed by spring,autumn and winter.The N:P ratio is high,with a mean values 49.47.It is indicats Phosphorus is a limiting element in Baihuahu reservoir.?4?Water temperature,dissolved oxygen,transparency,chlorophyll,permanganate index have important correlations with nitrogen?total nitrogen,ammonia nitrogen?in Baihuahu Reservoir.It indicates water environment affects spatial and temporal distribution characteristics of total nitrogen and ammonia nitrogen in Baihuahu reservoir.It indicates that microbial activities,decomposition of organic matter,nitrification and denitrification in water affect the formation and transformation of ammonia nitrogen and total nitrogen.In addition,the total phosphorus has a significant correlation with the permanganate index that indicats a great relationship with the decomposition of organic matter in Baihuahu reservoir. |
PDF Full Text Request