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Sensitivity of the marine biospheric Si cycle for biogeochemical parameter variations
Author(s) -
Heinze C.,
Hupe A.,
MaierReimer E.,
Dittert N.,
Ragueneau O.
Publication year - 2003
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2002gb001943
Subject(s) - biogeochemical cycle , biogenic silica , water column , settling , geochemical cycle , silicic acid , sediment , environmental science , flux (metallurgy) , biogeochemistry , tracer , geology , soil science , oceanography , environmental chemistry , chemistry , geomorphology , physics , organic chemistry , environmental engineering , nuclear physics
A systematic quantitative assessment of the marine silicon cycle is presented, based on a prognostic coupled water column‐sediment global biogeochemical ocean general circulation model (HAMOCC). The resulting tracer distributions are compared with a comprehensive marine Si database of measurements. The model parameters which govern the Si cycle within the model world are optimized through a linear response model. The functional relationships between the Si cycle parameters and the Si tracer distributions are derived from a series of sensitivity experiments addressing opal export production, particle flux through the water column, porewater chemistry, and external biogeochemical forcing. The most important parameters for a further quantitative improvement of the simulation are depth‐dependent opal dissolution kinetics, a productivity‐dependent opal settling velocity, a general change in maximum Si uptake velocity V max opal , and the clay as well as the Si input from continental weathering. The modeled Si budget shows a larger global export production, larger opal deposition rates onto the sediment surface and higher diffusive transports of porewater silicic acid into the open water column as estimated by Tréguer et al. [1995].