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Spring carbonate chemistry dynamics of surface waters in the northern E ast C hina S ea: Water mixing, biological uptake of CO 2 , and chemical buffering capacity
Author(s) -
Zhai WeiDong,
Chen JianFang,
Jin HaiYan,
Li HongLiang,
Liu JinWen,
He XianQiang,
Bai Yan
Publication year - 2014
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc009856
Subject(s) - alkalinity , carbonate , spring (device) , oceanography , surface water , chlorophyll a , chemistry , submarine pipeline , dissolved organic carbon , environmental chemistry , environmental science , geology , environmental engineering , mechanical engineering , biochemistry , organic chemistry , engineering
We investigated sea surface total alkalinity (TAlk), dissolved inorganic carbon (DIC), dissolved oxygen (DO), and satellite‐derived chlorophyll‐a in the connection between the Yellow Sea and the East China Sea (ECS) during April to early May 2007. In spring, Changjiang dilution water (CDW), ECS offshore water, and together with Yellow Sea water (YSW) occupied the northern ECS. Using 16 day composite satellite‐derived chlorophyll‐a images, several algal blooms were identified in the CDW and ECS offshore water. Correspondingly, biological DIC drawdown of 73 ± 20 μmol kg −1 , oversaturated DO of 10–110 μmol O 2 kg −1 , and low fugacity of CO 2 of 181–304 μatm were revealed in these two waters. YSW also showed CO 2 uptake in spring, due to the very low temperature. However, its intrusion virtually counteracted CO 2 uptake in the northern ECS. In the CDW and the ECS offshore water, Revelle factor was 9.3–11.7 and 8.9–10.6, respectively, while relatively high Revelle factor values of 11.4–13.0 were revealed in YSW. In the ECS offshore water, the observed relationship between DIC drawdown and oversaturated DO departed from the Redfield ratio, indicating an effect of chemical buffering capacity on the carbonate system during air‐sea reequilibration. Given the fact that the chemical buffering capacity slows down the air‐sea reequilibration of CO 2 , the early spring DIC drawdown may have durative effects on the sea surface carbonate system until early summer. Although our study is subject to limited temporal and spatial coverage of sampling, these insights are fundamental to understanding sea surface carbonate chemistry dynamics in this important ocean margin.