An overview on the variation of sea surface pCO₂ in Northern South China Sea and its management

Abstract

To have better understandings of the partial pressure of carbon dioxide (pCO2)in northern South China Sea(NSCS), the pCO2readings from 1999-2012 were reviewed. Both the pCO2in NSCS and in the atmosphere also showed an increasing trends and the pCO2in NSCS varied across the seasons. There are many important processes that influenced the pCO2in NSCS, which were the rise of the temperature, biological production, seasonal upwelling, Pearl River discharge, increase in the concentration of atmospheric pCO2and the rate of calcification. These six mechanisms extend different strengths on the resultant sea surface pCO2in NSCS. The impact of induced sea water acidification on the marine phytoplankton by the high pCO2in NSCS would also be discussed. The drop of pH in the seawater would change the community of phytoplankton from diatom to dinoflagellate as a resistance to the change of pH of dinoflagellate that was better than the diatom. DMS, which was one of the climatically important gases, would also affected by the high pCO2induced seawater acidification. Hong Kong (HK) was studied as a case to estimate whether NSCS also faced the same impacts upon by the marine phytoplankton. The study showed that the diatom was relatively sensitive to the drop of pH in HK waters. The DMS producing marine phytoplankton was also affected by the drop of pH in HK waters. It was concluded that the NSCS might also face the same situation with HK. Finally, three instruments were recommended to have a better management in NSCS, namely, knowledge gaps and NSCS research priorities, valuing the NSCS as well as decision making team. Firstly, filling the knowledge gaps and NSCS research priorities aim to enhance the ability of the ocean sequestration to absorb and store the largest amount of anthropogenic CO2as possible. Afterwards, valuing the NSCS aims to protect the marine organisms, such as the phytoplankton, form the negative impacts of the decrease of ocean acidity. Last but not least, a good decision making team aims to balance the conflicts between those various options to reduce the anthropogenic CO2with ocean sequestration and impacts result from the ocean sequestration.