汉江支流梯级水库氮磷营养盐分布及驱动因子

Tempo-spatial Distribution and Driving Factors of Nitrogen and Phosphorus of Cascade Reservoirs in the Upreach of Hanjiang River

基于汉江支流堵河梯级水库2019年1-10月的水环境调查数据,该文分析了堵河梯级水库氮磷营养盐的时空分布特征及驱动因素,并运用水质指数法(WQI)评价了堵河梯级水库的水质现状。单因素方差分析显示:堵河上游龙背湾水库的磷酸盐(PO43--P)高于中、下游,但无机氮(DIN)差异不显著(p>0.05),DIN中硝酸盐氮(NO3--N)占比最高(89.38%~97.52%),亚硝酸盐氮(NO2--N)最低(0.35%~0.80%),但各水库间差异不显著(p>0.05)。堵河梯级水库的N/P比值时空差异明显(p<0.05),1月为氮限制,4-10月为磷限制,中、上游为氮限制,下游为磷限制。皮尔逊相关性分析显示:PO43--P含量变化与电导率呈极显著正相关关系(p<0.01),与水温呈显著负相关关系(p<0.05),相关系数为0.38和-0.28。NO2--N与溶解氧和pH呈显著正相关关系(p<0.05),与高锰酸盐指数呈极显著正相关关(p<0.01),相关系数分别为0.35、0.31和0.45。水质评价显示:调查期间,堵河梯级水库的WQI均值为83.5,但有一定的时空异质性,上游水库的水质优于中、下游;10月水质优于1月、4月和7月。总之,堵河梯级水库水环境因子的变化存在时空异质性,WQI水质健康评价等级为良好,表明堵河梯级水库的水环境受到轻微的破坏。

Based on the measured data of Duhe River cascade reservoirs in the upreach of Hanjiang River from January 2019 to October,2019,the tempo-spatial distribution characteristics and driving factors of nitrogen and phosphorus nutrients were analyzed,and the water quality status was evaluated by using Water Quality Index(WQI).One-way ANOVA results showed that the phosphate(PO;-P)of upper reservoir(LBW)was significantly higher than that in middle(SSL)and lower(PK),while the dissolved inorganic nitrogen(DIN)had no significant difference(p>0.05).Nitrate nitrogen(NO;-N)dominated in DIN for the highest proportion(89.38%~97.52%),and nitrite nitrogen(NO;-N)was the lowest(0.35%~0.80%),but there were no significant difference among reservoirs(p>0.05).Difference in N/P(DIN/PO;-P)ratio among reservoirs were significant(p<0.05),with N-restricted in January and the middle and upper reservoirs,and P-restricted from April to October and lower reservoir.Pearson correlation analysis showed that PO;-P was significantly positively correlated with Cond(p<0.01),and negatively correlated with WT(p<0.05),with correlation coefficients of 0.38 and-0.28,respectively.NO;-N was significantly positively correlated with DO and pH(p<0.05),and extremely significantly positively correlated with COD;(p<0.01),with correlation coefficients of 0.35,0.31,and 0.45,respectively.The water quality evaluation showed that during the investigation period,the average WQI of Duhe cascade reservoirs was 83.5,but there was a certain spatialtemporal haterogeneity.The water quality of upper was better than that of middle and lower reservoirs.The water quality in October is better than that in January,April and July.In brief,the change of water enviromental factors in Duhe cascade reerviors was spatiotemporal hterogeneity,and the water quality health evaluation grade was good,indicating that the water environment of the Duhe cascade reservoirs had been slightly damaged.