The main objectives of the project are:
I) To provide a data base of observations and a general circulation model which allow comprehensive studies of the silicon cycling in the oceans;
II) To reproduce the first principles of silicon cycling in today's world ocean by use of an ocean general circulation model;
III) To offer an explanation for the present opaline sedimentary distribution;
IV) To test our improved understanding of opal by a paleoceanographic application of the model and compare the simulations with the observed sediment record.
In order to enable full use of the paleoclimatic information of the opal sediment record we propose as scientifically innovative steps to: - gather all existing observed Si and opal data for the present ocean including flux rates and summarize them in a combined data set which allows systematic statistical and analytical evaluation (task 1- data base), - present a first coupled three-dimensional ocean-sediment model including opal and early diagenesis processes on the basis of an ocean general circulation model velocity field which allows realistic regional resolution of large scale oceanic tracer fields (task 2 - model reference run), - use both tools to systematically diagnose model deficiencies (task 3 - comparison) and try to remove disagreements between model and observations for the present ocean by development of new parametrisations for marine Si cycling, in particular for opal dissolution under various conditions (task 4- optimisation), - apply the optimal model version to ocean velocity fields which represent the Last Glacial Maximum and the mid-Miocene (open/closed Central America isthmus) (task 5 - validation).The project is based on a close collaboration of experimental and modelling scientists. It will provide the scientific community with operationally working tools for the use of biogenic silica in paleoceanographic investigations. 06
Funding SchemeCSC - Cost-sharing contracts