Production of Carbon Dioxide From Sub-aerially Exposed Continental Shelves and Oceanic Islands During Glacial Periods Since the Middle Pleistocene Climatic Transition

The EPICA Dome C ice core has yielded an 800,000-year record of atmospheric carbon dioxide composition from the Middle Pleistocene climatic transition to the present day. In this record, there is a sharp increase in carbon dioxide immediately following the glacial maxima during the glacial periods which to date remains difficult to explain. We will present evidence to show that sub-aerially exposed continental shelves and oceanic islands may be at least partly responsible for the production of the missing carbon dioxide. In exposed siliciclastic-dominated shelves and oceanic islands, acid-sulphate soil development would lead to the release of carbon dioxide. On the other hand, in exposed carbonate-dominated shelves and oceanic islands, karstification would also lead to the release of carbon dioxide. Selected cores from continental shelves and oceanic islands will be used to support this claim. Further studies on cores obtained from other continental shelves and oceanic islands would facilitate the estimation of carbon dioxide loss through comparison between Holocene marine deposits and their pre-Holocene counterparts. Additionally, information on the vegetation history of exposed shelves and oceanic islands during glacial periods may be obtainable to supplement our knowledge gap on past changes in the biological pump.