地理气候及湖盆形态对我国湖泊营养状态的影响

利用SPSS统计分析软件的相关性分析和曲线估计功能分析了我国145个湖泊富营养化指标与自然因素之间的关系.富营养化指标包括2008—2010年现场监测的总氮、总磷、高锰酸盐指数、透明度、叶绿素a(Chla)和营养状态综合指数(TLI),自然因素包括:2个湖盆形态指标(平均水深和面积)、3个湖泊地理位置指标(经度、纬度和海拔)和3个气候指标(年均温、年平均降水量和>0℃积温).相关性分析的结果表明,TLI指数与湖泊平均水深和海拔呈显著负相关(p<0.01),而与湖泊所在经度、>0℃积温呈显著正相关(p<0.01,p<0.05).Chla与湖泊平均水深呈显著负相关(p<0.05),与年均温和>0℃积温呈显著正相关(p<0.05).曲线估计的分析结果表明,TLI与湖泊平均水深和经度呈幂函数关系,与海拔和>0℃积温呈指数函数关系.研究结果还表明,贫营养湖泊位于高海拔(>1000m)和低经度(<105°)地区,并且湖泊的平均水深大于30m.年平均降水量低于1000mm,>0℃积温低于5400℃.

Regional differences in physiographical, climatological and morphological effects on lake trophic status in China

Correlation analysis and curve estimation were used to explore the relationships between eutrophication parameters and natural factors in a large scale using data from 145 lakes across China.Lake eutrophication parameters including total nitrogen(TN),total phosphorus(TP),chemical oxygen demand(CODMn),chlorophyll-a(Chla),Secchi depth(SD),and trophic level index(TLI) were collected and monitored for the period 2008~2010.Natural factors included three of geographic location,two of lake morphology,and three of climate variables.Correlation analysis in SPSS was used to investigate the key drivers of lake eutrophication.The results showed that TLI was negatively related to lake depth and elevation,and positively related to longitude and accumulated temperature(>0℃).Chl a was negatively related to lake depth and positively related to annual temperature and accumulated temperature(>0℃).Curve estimation indicated that TLI exhibited power function relationships with lake depth and longitude,and exponential function relationships with elevation and accumulated temperature(>0℃).The results also showed that oligotrophic lakes were generally located in higher altitude(>1000m) and lower longitude(<105°).The depth of oligotrophic lakes was deeper than 30m,with annual precipitation less than 1000mm and accumulate temperature(>0℃) lower than 5400 ℃.