春季黄海与渤海一氧化碳的浓度分布、海-气通量和光生产的研究

Distribution,Flux and Photoproduction of Carbon Monoxide in the Yellow Sea and the Bohai Sea in Spring

在春季开展了黄海与渤海表层海水和上方大气中CO的浓度分布、海-气通量和表层海水中CO的光化学生产的研究.用顶空分析法测得表层海水中CO的浓度([CO]surf)为(0.19～3.57)nmol.L-1,平均值为1.24 nmol.L-1(SD=0.79,n=69);总体来看,[CO]surf的分布呈现出近岸高、远海低的趋势.CO的浓度按取样和测试时间以小时为单位分割求平均值,该平均浓度表现出周日变化的特征,中午最高,凌晨最低,最大值约为最小值的10倍.黄海与渤海大气中CO的体积分数在215×10-9～850×10-9之间,平均值为414×10-9(SD=140×10-9,n=69),说明黄、渤海海区大气中CO的含量受到陆源输入的影响显著.黄、渤海表层海水均处于过饱和状态,CO的过饱和系数为0.42～18.90,平均值为3.61(SD=2.99,n=69),表明黄、渤海海水是大气CO的净源.CO的海-气通量采用LM86和W92这2个公式计算,平均通量分别为(1.22±1.70)μmol.(m2.d)-1和(2.13±2.91)μmol.(m2.d)-1.运用SMARTS2模型计算得到的黄、渤海的CO光化反应产率为54.60μmol.(m2.d)-1,整个调查区域的春季光致生成碳的量为26.95×109 g.光化学反应产率约为海-气交换通量的25～50倍,说明黄、渤海表层海水中的CO大部分被微生物所消耗.

Concentration distribution,sea-to-air flux,photoproduction of carbon monoxide（CO） in the surface seawater and atmospheric CO mixing ratio were measured in the Yellow Sea and the Bohai Sea.A headspace analysis system was used for CO measurement.The concentrations of CO in the surface seawater ranged from 0.19 to 3.57 nmol·L-1,with an average of 1.24 nmol·L-1（SD=0.79,n=69）.Overall,the concentrations of CO displayed a decreasing trend from the coast to the offshore stations and followed diurnal variations after classifying and averaging the CO concentrations according to sampling and analyzing time in the unit of one hour,with the maximum values in midnoon which was 10 folds higher than the minimum values in predawn.Atmospheric CO mixing ratios varied from 215×10-9 to 850×10-9,with an average of 414 ×10-9（SD=140×10-9,n=69）,due to obvious terrestrial input.The supersaturation factors of CO varied from 0.42-18.90,with an average of 3.61（SD=2.99,n=69）,indicating that the Yellow Sea and the Bohai Sea was a net source of atmospheric CO.The average sea-to-air fluxes of CO from the Yellow Sea and the Bohai Sea were estimated to be（1.22±1.70） μmol·（m2·d）-1 by the LM86 equation and（2.13±2.91） μmol·（m2·d）-1 by the W92 equation,respectively.Using SMARTS2 spectral irradiance model to estimate CO production,the photoproduction rate of CO was 54.60 μmol·（m2·d）-1 and the photoproduction of carbon in the Yellow Sea and the Bohai Sea was 26.95×109g in spring.The photoproduction rate of CO was 25-50 times higher than the sea-to-air flux,suggesting that most part of CO was removed by microbial process in the surface seawater.