Origin and fate of biogenic particle fluxes in the ocean and their interaction with the atmospheric CO2 concentration as well as the marine sediment. (ORFOIS)

The main scientific objectives of project ORFOIS are to:

• identify and quantify globally the mechanisms underlying the transformation of biogenic particles to dissolved substances within the ocean water column in order to predict correctly surface ocean carbon dioxide sources and sinks;
• develop a refined particle flux model for operational use in ocean general circulation models which realistically describes particle dynamics in the water column, deposition of material to the sediment, and the interaction with the carbon dioxide partial pressure pCO2;
• provide a global closed carbon and nutrient budget for modern (preindustrial) conditions including the water column sediment interaction;
• estimate the changes in CO2 sea surface source sink patterns and vertical redistributions of carbon as well as nutrients for future global change, climate change as well as carbon sequestration scenarios including the associated potential economic impacts.

The ORFOIS project focused on the origin and fate of biogenic particle fluxes in the ocean and their interaction with the atmospheric CO2, as well as the marine sediment. Part of the project objectives included the development of a refined particle flux model for operational use in ocean general circulation models. The improved model needs to realistically describe particle dynamics in the water column, deposition of material to the sediment and the interaction with the partial pressure of CO2 (pCO2).

Compared to other state-of-the-art closed system models (Hamburg Model of the Ocean Carbon Cycle) the newly improved model is more realistic and more sensitive to changes in the potential driving mechanisms for glacial pCO2 reduction.