Coastal observation of halocarbons in the Yellow Sea and East China Sea during winter: Spatial distribution and influence of different factors on the enzyme-mediated reactions

Yawen Zou; Zhen He; Chun-Ying Liu; Qianqian Qi; Gui-Peng Yang; Shihai Mao

doi:10.1016/j.envpol.2021.118022

Coastal observation of halocarbons in the Yellow Sea and East China Sea during winter: Spatial distribution and influence of different factors on the enzyme-mediated reactions

Environ Pollut. 2021 Dec 1:290:118022. doi: 10.1016/j.envpol.2021.118022. Epub 2021 Aug 21.

Authors

Yawen Zou¹, Zhen He², Chun-Ying Liu², Qianqian Qi¹, Gui-Peng Yang³, Shihai Mao¹

Affiliations

¹ Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
² Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Institute of Marine Chemistry, Ocean University of China, Qingdao, 266100, China.
³ Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Institute of Marine Chemistry, Ocean University of China, Qingdao, 266100, China. Electronic address: gpyang@ouc.edu.cn.

PMID: 34492527
DOI: 10.1016/j.envpol.2021.118022

Abstract

Volatile brominated compounds are important trace gases for stratospheric ozone chemistry. In this study, the spatial variations of dibromomethane (CH₂Br₂), bromodichloromethane (CHBrCl₂), dibromochloromethane (CHBr₂Cl) and bromoform (CHBr₃) in the seawater and overlying atmosphere were measured in the Yellow Sea (YS) and the East China Sea (ECS) in winter. The air-sea fluxes of CH₂Br₂, CHBrCl₂, CHBr₂Cl and CHBr₃ ranged from -11.46 to 25.33, -4.68 to 7.91, -8.60 to 4.08 and -88.57 to 8.84 nmol m^-2·d^-1, respectively. In order to understand the mechanism of halocarbons production, we measured bromoperoxidase (BrPO) activity (39.18-186.74 μU·L^-1) in the YS and ECS for the first time using an aminophenyl fluorescein (APF) method and performed in-situ incubation experiments in BrPO-treated seawater. The production rates of CH₂Br₂, CHBrCl₂, CHBr₂Cl and CHBr₃ ranged from 14.21 to 94.74, 0.00 to 19.74, 0.00 to 30.62 and 6.18-72.75 pmol L^-1·h^-1, respectively, in BrPO-treated seawater. There were significantly higher production rates in coastal waters compared with the open sea (P = 0.016) because of higher DOC levels near the coast. Moreover, the production rates of halocarbons increased with BrPO activity and H₂O₂ concentration. The results showed that enzyme-mediated reaction was an important source for the production of halocarbons in seawater. The present research is of great significance for understanding the production mechanisms of halocarbons in seawater and global oceanic halocarbons emissions.

Keywords: Bromoperoxidase activity; Distribution; Halocarbons; Hydrogen peroxide; Yellow sea and East China Sea.

MeSH terms

Air Pollutants* / analysis
China
Environmental Monitoring*
Hydrogen Peroxide
Oceans and Seas
Peroxidases
Seawater

Substances

Air Pollutants
Hydrogen Peroxide
Peroxidases
bromide peroxidase