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Seasonal Variations and Drivers of Surface Ocean pCO(2) in the Seasonal Ice Zone of the Eastern Indian Sector, Southern Ocean
Title: | Seasonal Variations and Drivers of Surface Ocean pCO(2) in the Seasonal Ice Zone of the Eastern Indian Sector, Southern Ocean |
Authors: | Tozawa, Manami Browse this author | Nomura, Daiki Browse this author →KAKEN DB | Nakaoka, Shin-ichiro Browse this author →KAKEN DB | Kiuchi, Masaaki Browse this author | Yamazaki, Kaihe Browse this author | Hirano, Daisuke Browse this author | Aoki, Shigeru Browse this author →KAKEN DB | Sasaki, Hiroko Browse this author | Murase, Hiroto Browse this author |
Keywords: | carbonate chemistry | sea-air CO2 flux | carbon cycle | Southern Ocean |
Issue Date: | Jan-2022 |
Publisher: | American Geophysical Union |
Journal Title: | Journal of Geophysical Research Oceans |
Volume: | 127 |
Issue: | 1 |
Start Page: | e2021JC017953 |
Publisher DOI: | 10.1029/2021JC017953 |
Abstract: | To quantitatively assess the inorganic carbon cycle in the eastern Indian sector of the Southern Ocean (80-150 degrees E, south of 60 degrees S), we measured ocean surface temperature, salinity, total alkalinity (TA), the partial pressure of carbon dioxide (pCO(2)), and concentrations of chlorophyll-a (chl a), dissolved inorganic carbon (DIC), and nutrients during the KY18 survey (December 2018-January 2019). The sea-air CO2 flux in this region was -8.3 +/- 12.7 mmol m(-2) day(-1) (-92.1 to +10.6 mmol m(-2) day(-1)). The ocean was therefore a weak CO2 sink. Based on the DIC and TA in the temperature minimum layer, we estimated the change of pCO(2) from winter to summer (delta pCO(2)) due to changes in water temperature, salinity, and biological activity (photosynthesis). The spatial distribution of pCO(2) in the western part (80-110 degrees E) of the study area was mainly driven by biological activity, which decreased pCO(2) from December to early January, and in the eastern part (110-150 degrees E) by temperature, which increased pCO(2) from January to February. We also examined the changes in the CO2 concentrations (xCO(2)) over time by comparing data from 1996 with our data (2018-2019). The oceanic and atmospheric xCO(2) increased by 23 and 45 ppm in 23 years, respectively. These changes of ocean xCO(2) were mainly driven by an increase in CO2 uptake from the atmosphere as a result of the rise in atmospheric xCO(2) and increase in biological activity associated with the change in the water-mass distribution. |
Type: | article |
URI: | http://hdl.handle.net/2115/84341 |
Appears in Collections: | 水産科学院・水産科学研究院 (Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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