春季东海一氧化碳的浓度分布、海-气通量、微生物消耗和暗反应生成研究

Distribution, flux, microbial consumption and dark production of carbon monoxide in the East China Sea in spring

为了探究陆架海域在全球海洋一氧化碳(CO)的生物地球化学循环中的地位,本文于2021年春季在中国东海对CO的浓度分布、海-气通量、暗反应生产和微生物消耗进行了研究。结果表明,东海大气中CO的体积分数为126.07×10^(-9)~353.15×10^(-9),平均值为(191.32±51.52)×10^(-9),呈现明显的近岸高、远海低的特点。表层海水中CO的浓度为0.83~4.08 nmol/L,平均值为(2.07±0.84)nmol/L,最大值出现在舟山群岛附近,最小值出现在夜间采样站位,受太阳辐射强度和陆源输入有机物的影响较大。近岸海水中CO的垂直分布呈现表层浓度高、随深度增加浓度逐渐减小的趋势。表层海水中CO的过饱和系数为4.98~24.96,平均值为13.94±5.77。CO的日海-气通量为2.62~9.38μmol/(m^(2)·d),平均值为(6.70±2.62)μmol/(m^(2)·d)。在CO的暗反应生成培养实验中,CO浓度随时间增长呈现线性增加的趋势,生成速率为0.024~0.50 nmol/(L·h),平均值为(0.20±0.14)nmol/(L·h),且与a350呈线性相关关系。表层海水中CO的微生物消耗速率常数为0.034/h~0.24/h,平均值为(0.11±0.08)/h。本文初步探究了中国陆架海域CO的暗反应生产,为构建中国陆架海域CO的生物地球化学循环体系提供了基础数据,有助于进一步认识陆架海域在全球海洋CO生物地球化学循环中的地位。

In order to explore the significance of shelf sea in the global biogeochemical cycle of marine carbon monoxide(CO), the distribution, flux, dark production and microbial consumption of CO were investigated in the East China Sea during spring in 2021. Atmospheric CO mixing ratios ranged from 126.07 ×10^(-9)to353.15 ×10^(-9), with an average of(191.32 ± 51.52) ×10^(-9), showing an obvious decreasing trend from coastal waters to open sea. The concentrations of CO in the surface seawater ranged from 0.83 to 4.08 nmol/L, with an average of(2.07 ± 0.84) nmol/L. The highest value appeared near Zhoushan Islands and the lowest value was measured at sampling stations at night, presenting evident influence by solar radiation intensity and terrestrial organic matter. The result of vertical distribution of CO in coastal waters presented that high concentration of CO occurred in the surface seawater and then decreased with increasing depth. The supersaturation factors of CO in the surface seawater varied from 4.98 to 24.96, with a mean of(13.94 ± 5.77). The sea-to-air fluxes of CO ranged from 2.62 to 9.38 μmol/(m^(2)·d) with the mean of(6.70 ± 2.62) μmol/(m^(2)·d). In the incubation experiments of dark production of CO, the concentration of CO increased linearly with the increase of time.Dark production rate varied from 0.024 to 0.50 nmol/(L·h), with the average of(0.20 ± 0.14) nmol/(L·h). There was a linear correlation between a350 and dark production rate of CO. Microbial consumption rate constants of CO varied from 0.034/h to 0.24/h, with the mean of(0.11 ± 0.08)/h. This research preliminarily investigates the dark production of CO in the nearshore area of China, which provides basic data for the construction of the biogeochemical cycle system of CO in the continental shelf area of China, and helps to deepen our understanding of the role of continental shelf areas in the biogeochemical cycle of CO in the global ocean.