洱海总有机碳的时空分布特征及其影响因素

Spatial-temporal Distribution Characteristics and Influencing Factors of Total Organic Carbon in Erhai Lake

为研究洱海水体总有机碳(TOC)的空间分布特征,逐月调查了2018年3月—2019年2月洱海水体11个点位总有机碳含量,探讨TOC与环境因子(水温(WT)、pH值、透明度(SD)、溶解氧(DO)、COD Cr、COD Mn、总磷(TP)、总氮(TN)、氨氮(NH 3-N)、叶绿素a(Chl a)、藻类细胞密度D)之间的关系。结果表明:洱海TOC的浓度范围为3.04~10.83 mg/L,年平均值为6.10±1.72 mg/L,夏季(6—8月)、秋季(9—11月)、冬季(12—2月)、春季(3—5月)TOC浓度呈现由大变小的趋势。Pearson相关分析显示(n=132):洱海TOC与COD Cr(r=0.913,p<0.01)、WT(r=0.801,p<0.01)、TP(r=0.730,p<0.01)、COD Mn(r=0.689,p<0.01)、NH 3-N(r=0.615,p<0.01)、Chla(r=0.530,p<0.01)、TN(r=0.383,p<0.01)、D(r=0.301,p<0.01)之间均呈显著的正相关,与SD(r=-0.654,p<0.01)、DO(r=-0.461,p<0.01)呈显著负相关,与pH(r=0.183,p<0.05)相关性不显著。洱海水体中的TOC含量是外源输入、内源产生、湖内迁移转化等多个过程动态平衡的结果,TOC浓度的时空分布也受到流域内降雨、农事活动、污水排放、施工、旅游活动、生物活动等的影响。

In order to study the spatial distribution characteristics of total organic carbon(TOC)in the Erhai water body,the total organic carbon content at 11 points in the Erhai water body from March 2018 to February 2019 was investigated monthly.The relationship among TOC and environmental factors water temperature(WT),pH value,transparency(SD),dissolved oxygen(DO),COD Cr,COD Mn,total phosphorus(TP),total nitrogen(TN),ammonia nitrogen(NH 3-N),chlorophyll a(Chl a),algae cell density are studied.The results showed that the concentration of TOC in Erhai Lake ranged from 3.04-10.83mg/L,and the annual average was 6.10±1.72mg/L.,the TOC concentration showed a trend from large to small in the following seasons summer(June-August),autumn(September-November),winter(December-February)and spring(March-May).Pearson correlation analysis showed(n=132)that TOC showed positive relationship with COD Cr(r=0.913,p<0.01),WT(r=0.801,p<0.01),TP(r=0.730,p<0.01),COD Mn(r=0.689,p<0.01),NH 3-N(r=0.615,p<0.01),Chla(r=0.530,p<0.01),TN(r=0..383,p<0.01),D(r=0.301,p<0.01).It significantly negatively correlated with SD(r=-0.654,p<0.01),DO(r=-0.461,p<0.01).There is no significant correlation between pH and TOC(0.183,p<0.05).The TOC content in Erhai Lake is the result of the dynamic balance of multiple processes such as exogenous input,endogenous production,and migration and transformation in the lake.The temporal and spatial distribution of TOC concentration was also affected by rainfall,agricultural activities,sewage discharge,construction,tourism activities,and the biological activities etc.