万峰湖水库冬季CO2通量与p(CO2)分布特征及形成机制

Distribution Characteristics and Formation Mechanism of CO Flux and p(CO) of Wanfenghu Lake Reservoir in Winter

为研究万峰湖水库冬季CO2通量与p(CO2)分布特征及形成机制,作者于2017年2月对万峰湖水库进行走航采样研究,结果表明:水平方向上,p(CO2)取值范围为158.65~371.53 Pa,均值为254.17 Pa;CO2通量取值范围为39.35~102.83 mmol/(m2·d),均值为65.21 mmol/(m2·d)。垂直剖面上,CO2分压与CO2通量随水深增加而增加,均值分别为423.50 Pa、114.87 mmol/(m2·d),总体表现为CO2的"源",且回水区>干流>马岭河支流。表水层p(CO2)和CO2通量变化速率为F-1>F-4>F-2>F-3,温跃层为F-1>F-3>F-2>F-4,低温层为F-4>F-1。与其他气候带河流、湖泊、水库相比,CO2通量处于中等偏高水平。马岭河支流、干流和回水区p(CO2)形成机制分别与浮游植物的呼吸作用、有机质的降解、外源河流的输入、碳酸盐的沉淀及底泥溢出的CO2有关。同时,回水区封闭库湾的"死水"区域也是导致p(CO2)及CO2通量高的又一原因。

In order to study the distribution characteristics and formation mechanism of CO2 flux and p(CO2)in Wanfenghu Lake Reservoir in winter,a navigational sampling study was carried out in February 2017.The results show that in the horizontal direction,the range of p(CO2)is 158.65~371.53 Pa,with the average value of 254.17 Pa;the range of CO2 flux is39.35~102.83 mmol/(m2·d),with the average value as 65.21 mmol/(m2·d).On the vertical profile,the partial pressure of CO2 and the flux of CO2 increase with the increase of water depth,with the average values being 423.50 Pa and 114.87 mmol/(m2·d),respectively.They are generally the"source"of CO2,with the backwater area>mainstream>a tributary of Maling River.The change rate of p(CO2)and CO2 flux in the surface water layer is F-1>F-4>F-2>F-3,the thermocline is F-1>F-3>F-2>F-4,and the cryogenic layer is F-4>F-1.Compared with other climatic zones rivers,lakes,and reservoirs,CO2 flux is at a moderately high level.The formation mechanism of p(CO2)in the tributaries of Maling River,mainstream and backwater area is related to the respiration of phytoplankton,the degradation of organic matter,the input of external rivers,the precipitation of carbonates and the CO2 spilled from the bottom sludge.At the same time,the"dead water"area of the closed reservoir bay in the backwater area is another reason for the high flux of p(CO2)and CO2.