Carbonate chemistry variability in the southern Yellow Sea and East China Sea during spring of 2017 and summer of 2018

Xue Deng; Gui-Ling Zhang; Ming Xin; Chun-Ying Liu; Wei-Jun Cai

doi:10.1016/j.scitotenv.2021.146376

Carbonate chemistry variability in the southern Yellow Sea and East China Sea during spring of 2017 and summer of 2018

Sci Total Environ. 2021 Jul 20:779:146376. doi: 10.1016/j.scitotenv.2021.146376. Epub 2021 Mar 16.

Authors

Xue Deng¹, Gui-Ling Zhang², Ming Xin³, Chun-Ying Liu⁴, Wei-Jun Cai⁵

Affiliations

¹ Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, PR China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; School of Marine Science and Policy, University of Delaware, Newark, DE 19716, United States.
² Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, PR China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China.
³ Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; Key Laboratory for Marine Bioactive Substances and Modern Analytical Technology, the First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, PR China.
⁴ Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, PR China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China. Electronic address: roseliu@ouc.edu.cn.
⁵ School of Marine Science and Policy, University of Delaware, Newark, DE 19716, United States.

PMID: 33752023
DOI: 10.1016/j.scitotenv.2021.146376

Abstract

Marginal seas are highly productive and disproportionately large contributors to global air-sea CO₂ fluxes. Due to complex physical and biogeochemical conditions, the southern Yellow-East China Sea is an ideal site for studying carbonate chemistry variability. The carbonate system was investigated in the area in spring of 2017 and summer of 2018. Dissolved inorganic carbon (DIC) and total alkalinity (TA) concentrations were higher in the SYS than the ECS due to material from carbonate weathering and erosion carried by the Yellow River. High pH and low DIC and TA were observed in the Zhe-Min Coastal Current in spring due to high primary productivity caused by Changjiang River input and the Taiwan Warm Current. Temperature and biological activity were the primary drivers controlling the partial pressure of CO₂ (pCO₂) in the SYS, pCO₂ was controlled by primary productivity related to nutrients carried by the Changjiang River and physical mixing in the Changjiang River plume and inner/middle shelves of the ECS, whereas temperature was the dominant factor determining pCO₂ distributions in the ECS outer shelf waters influenced by the Kuroshio Current. Overall, the entire study area shifted from a CO₂ sink (-4.18 ± 5.60 mmol m^-2 d^-1) to a weak source (1.02 ± 4.87 mmol m^-2 d^-1) from spring to summer. Specifically, the SYS and ECS offshore waters changed from CO₂ sinks in spring to sources in summer, while the Changjiang River plume was always a CO₂ sink.

Keywords: Air-sea CO(2) flux; Carbon cycle; Carbonate system; East China Sea; Southern Yellow Sea.