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; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, 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; EnvironmentResearch Institute, Shandong University, Qingdao, 266237, China.
Environ Pollut. 2021 Feb 1;270:116305. doi: 10.1016/j.envpol.2020.116305. Epub 2020 Dec 15.
The spatial distributions, fluxes, and environmental effects of non-methane hydrocarbons (NMHCs) were investigated in the Yellow Sea (YS) and the East China Sea (ECS) in spring. The average concentrations of ethane, propane, i-/n-butane, ethylene, propylene and isoprene in the seawater were 18.1 ± 6.4, 15.4 ± 4.7, 6.8 ± 2.9, 6.4 ± 3.2, 67.1 ± 26.7, 20.5 ± 8.7 and 17.1 ± 11.1 pmol L, respectively. The alkenes in the surface seawater were more abundant than their saturated homologs and NMHCs concentrations (with the exception of isoprene) decreased with carbon number. The spatial variations of isoprene were consistent with the distributions of chlorophyll a (Chl-a) and Chaetoceros, Skeletonema, Nitzschia mainly contributed to the production of isoprene, while the others' distributions might be related to their photochemical production. Observations in atmospheric NMHCs indicated alkanes in the marine atmosphere decreased from inshore to offshore due to influence of the continental emissions, while alkenes were largely derived from the oceanic source. In addition, no apparent diurnal discrepancy of atmospheric NMHCs (except for isoprene) were found between daytime and night. As the main sink of NMHCs in seawater, the average sea-to-air fluxes of ethane, propane, i-/n-butane, ethylene and propylene were 31.70, 29.75, 18.49, 15.89, 239.6, 67.94 and 52.41 nmol m d, respectively. The average annual emissions of isoprene accounted for 0.1-1.3% of the global ocean emissions, which indicated that the coastal and shelf areas might be significant sources of isoprene. Furthermore, this study represents the first effort to estimate the environmental effects caused by NMHCs over the YS and the ECS and the results demonstrated contributions of alkanes to ozone and secondary organic aerosol (SOA) formation were lower than those of the alkenes and the largest contributor was isoprene.
本研究于春季调查了黄海（YS）和东海（ECS）中非甲烷烃（NMHCs）的空间分布、通量及其环境效应。海水中乙烷、丙烷、异丁烷/正丁烷、乙烯、丙烯和异戊二烯的平均浓度分别为 18.1±6.4、15.4±4.7、6.8±2.9、6.4±3.2、67.1±26.7、20.5±8.7 和 17.1±11.1 pmol L。表层海水中的烯烃比其饱和同系物更丰富，并且 NMHCs 浓度（异戊二烯除外）随碳数的增加而降低。异戊二烯的空间变化与叶绿素 a（Chl-a）和菱形藻、骨条藻、角毛藻的分布一致，异戊二烯主要由菱形藻、骨条藻、角毛藻产生，而其他生物的分布可能与其光化学产生有关。大气 NMHCs 的观测结果表明，由于大陆排放的影响，烷烃从近岸向近海减少，而烯烃主要来自海洋源。此外，在白天和夜间，大气 NMHCs（异戊二烯除外）没有明显的日变化差异。作为海水中 NMHCs 的主要汇，乙烷、丙烷、异丁烷/正丁烷、乙烯和丙烯的海-气通量平均值分别为 31.70、29.75、18.49、15.89、239.6、67.94 和 52.41 nmol m d。异戊二烯的年平均排放量占全球海洋排放量的 0.1-1.3%，这表明沿海和陆架地区可能是异戊二烯的重要来源。此外，本研究首次估算了 YS 和 ECS 中非甲烷烃造成的环境影响，结果表明，烷烃对臭氧和二次有机气溶胶（SOA）形成的贡献低于烯烃，最大贡献者是异戊二烯。
