Frontiers Science Center for Deep Ocean Multispheres and Earth System, And Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
Frontiers Science Center for Deep Ocean Multispheres and Earth System, And Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China; Institute of Marine Chemistry, Ocean University of China, Qingdao, 266100, China.
Environ Pollut. 2021 May 1;276:116749. doi: 10.1016/j.envpol.2021.116749. Epub 2021 Feb 16.
Methyl iodide (CHI) released from ocean is an important carrier of iodine, which plays an important role in ozone depletion in the atmosphere. Depletion of ozone has increased the amount of ultraviolet radiation that reaches the earth's surface and recent global warming has caused oceanic acidification as well as dust events, but how these environmental changes will affect CHI concentration in the ocean is unclear. In this study, the spatial distributions and sources of CHI in the atmosphere, seawater, and sediment porewater were measured in the Yellow Sea (YS) and the East China Sea (ECS) between June and July 2018. Higher concentrations in the atmosphere, seawater, and sediment were found in the YS than in the ECS, and surface seawater emissions were discovered to be the major contributors of atmospheric CHI concentrations. Anthropogenic pollutants could explain significant spatial variation in the distribution of CHI. High concentrations of CHI in sediment porewater increased diffusion into bottom waters, with diffusive fluxes of 0.2-6.5 nmol m d. Preliminary results during the in situ seawater incubation experiments showed that the photochemical production rate of CHI ranged from 0.008 to 0.214 pmol L h under ultraviolet light, and an enhancement emission of CHI from phytoplankton occurred with the addition of dust, while a reduction of CHI appeared under lower pH conditions.
碘甲烷（CHI）从海洋中释放出来是碘的重要载体，在大气臭氧消耗中起着重要作用。臭氧的消耗增加了到达地球表面的紫外线辐射量，而最近的全球变暖导致了海洋酸化和沙尘事件，但这些环境变化将如何影响海洋中的 CHI 浓度尚不清楚。在这项研究中，于 2018 年 6 月至 7 月期间，在黄海（YS）和东海（ECS）测量了大气、海水和沉积物孔隙水中 CHI 的空间分布和来源。在大气、海水和沉积物中，YS 的浓度高于 ECS，并且发现表层海水排放是大气 CHI 浓度的主要贡献者。人为污染物可以解释 CHI 分布的显著空间变化。高浓度的 CHI 存在于沉积物孔隙水中，增加了向底层水的扩散，扩散通量为 0.2-6.5 nmol m d。原位海水培养实验的初步结果表明，在紫外线下，CHI 的光化学产生率在 0.008 到 0.214 pmol L h 之间变化，添加沙尘会导致 CHI 的增强排放，而在较低 pH 条件下，CHI 会减少。
