In order to explore the diurnal variation of water quality factors in different layers of crab ecoculture ponds,the water quality factors in upper,middle and lower layers of 3 ponds in Maogang area,Songjiang,Shanghai were monitored day and night for 3 consecutive sunny days in August 2014.The results showed that there were diurnal variation and stratification in all the water quality factors.There were no significant differences in the diurnal variations of water temperature,pH,CODMn concentration and PO43--P concentration in the 3 water layers.The difference of DO concentration and NO2--N concentration in the upper and lower water layers was significant.The concentration of NH4+-N and NO3--N in the 3 water layers were significantly different.In a day,the water temperature,DO concentration,pH and NO3--N concentration were lowest at 5:00,NH4+-N and NO2--N concentrations were the highest at 5:00,CODMn concentration was the highest at 1:00,PO43--P concentration was relatively stable.There was a negative correlation between the diurnal variation of NH4+-N concentration and DO concentration.%为了探究河蟹生态养殖池塘不同水层水质因子昼夜变化规律,于2014年8月选择3个连续的晴天天气对上海松江泖港地区3个河蟹生态养殖池塘上层、中层和下层的水质因子进行昼夜监测.结果表明:水质因子均存在昼夜变化和分层现象,3个水层的水温、pH、CODMn浓度和pO34--P浓度昼夜变化差异不显著;上层和下层水体的DO浓度和NO2--N浓度差异显著;3个水层的NH4+-N浓度和NO3--N浓度均表现出显著差异.一天中,水温、DO浓度、pH和NO3--N浓度在5:00最低,NH4-N、NO2--N浓度在5:00最高,CODMn浓度在1:00最高,PO3--P浓度较稳定;NH4+-N浓度和DO浓度的昼夜变化表现出负相关关系.
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