An initial study on ocean acidification in Southern waters of Vietnam

Phu Le Hung; Tuan Linh Vo Tran; Ngoc Pham Hong

doi:10.15625/1859-3097/16051

Author affiliations

Authors

Phu Le Hung Institute of Oceanography, VAST, Vietnam
Tuan Linh Vo Tran Institute of Oceanography, VAST, Vietnam
Ngoc Pham Hong Institute of Oceanography, VAST, Vietnam

DOI:

https://doi.org/10.15625/1859-3097/16051

Keywords:

Ocean acidification, Southern waters of Vietnam, aragonite, pH, CO2, CO32-, pCO2.

Abstract

Ocean acidification (OA) refers to the increase of dissolved CO₂and the reduction in the pH of seawater as a consequence of the absorption of large amounts of carbon dioxide (CO₂) by the oceans. This process is the result of large quantities of CO₂, produced by vehicles and industrial and agricultural activities. Over the past decades there have been many worldwide studies focusing on potential impacts of OA. However, researches regarding this issue remain scarce in Vietnam. In this paper, data of pH, total alkalinity (TA), dissolved inorganic carbon (HCO₃^-, CO₃^2-, CO₂), partial pressure of CO₂ (pCO₂) and the state of aragonite saturation (Ω_ar) measured in Southern waters of Vietnam in 2018 were used to: (1) Provide the initial data of OA parameters in Southern waters of Vietnam; (2) Compare the current situation of OA in Southern waters of Vietnam with the situation of world oceans. The results showed that mean values of pH, TA and CO₃^2- concentrations were 8.04 (7.92–8.11), 2300.28 µmol/kgSW (2,144.10–2,523.15), 218.83 µmol/kgSW (151.32–262.83), respectively. These values were higher in offshore areas than in coastal areas, especially at the estuaries. The average value of pCO₂ was 414.47 µatm (327.93–568.59), higher when compared with that of other areas (370 µatm). On the other hand, the state of aragonite saturation of the studied area had the similar patterns of TA and CO₃^2- concentrations. Most of values were always greater than 3, with this saturation state, the marine calcifiers are more likely to survive and reproduce.

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