Study on the Total Organic Carbon Characteristics of Reservoirs in Karst Areas during Abundant and Dry Season:Take the Pingban Reservoir as an Example
In order to study the concentration level,spatial and temporal distribution characteristics and influ-encing factors of organic carbon in Karst areas,and reveal the carbon cycle rules of river reservoirs in Karst areas,water samples were collected and ρTOC together with other physicochemical factors were determined in Pingban Reser-voir in July and December 2022,and the correlation analysis between ρTOC and main environmental factors was con-ducted.The results show that the concentration of ρTOC in Pingban reservoir shows obvious spatial and temporal differ-entiation,ranging from 1.899 to 8.057 mg·L-1,the average concentration are 5.215 mg·L-1 and 3.336 mg·L-1 during the wet and dry period,respectively.There were significant spatial differences in ρTOC in the reservoir area during the wet period,with the highest ρTOC distribution at sampling site 1 near the dam site and the lowest concentration in the upstream area into the lake.The ρTOCdistribution of the whole lake is stable during the dry season.The spatial difference of surface temperature(TW),pH,and nitrate nitrogen ρ(NO-3-N)is small,the standard deviation of conductivity(γCOND)and total dissolved solid(ρTDS)is large,and the dispersion of data at each point is obvious.The correlation analysis shows that ρTOC is significantly positively associated with TW,pH,ρ(NO-3-N),and ρ(NO-2-N).The study found that the ρTOC concentration of the Pingban reservoir is at the medium level compared with other lakes,which is related to the water area and storage capacity;the organic carbon of Pingban reservoir is the result of the joint influence of runoff carrying nutrient salt into the lake and phytoplankton growth for photosynthesis.
total organic carbonpluvial and dry seasonPingban reservoirspatial and temporal differentiation
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