| Jeandel et al (2011) suggested that sediments of continental origin deposited along ocean margins are capable of releasing a significant proportion of their constituting elements to seawater. These authors underline that this release could significantly contribute to the geochemical and isotopic budgets of various species in the oceans, including Si. However, the release processes are not yet understood, and there is an urgent need to progress in this issue yielding an important component of the land-to-ocean flux. Theoretically carbonate, organic, or Fe-Si complexation on the particle surface can modify the solubility of mineral species. Direct or indirect impact from bacterial activity and/or the differential dissolution of minerals within the particle pool can also occur and yield this release. This talk will propose how different surface particle speciation can enhance element releases. It will also propose several experimental tracks and how the use of cutting edge analytical tools allowing the direct exploration of the particle surface speciation could help our oceanographic community to progress in the understanding of these processes, an essential prerequisite for the Earth System modelling. |