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Control mechanisms for the oceanic distribution of silicon isotopes
Author(s) -
Wischmeyer André G.,
De La Rocha Christina L.,
MaierReimer Ernst,
WolfGladrow Dieter A.
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 - 10.1029/2002gb002022
Subject(s) - silicic acid , silicon , isotopes of silicon , geology , isotope , silicic , stable isotope ratio , oceanography , sediment , environmental science , geochemistry , chemistry , paleontology , volcano , physics , organic chemistry , quantum mechanics
Marine diatoms take up silicic acid for the buildup of their opaline shells and discriminate against the heavier silicon isotope. For the first time, the overall oceanic distribution of silicon isotopes has been estimated by integration of the Hamburg Model of the Ocean Carbon Cycle, version 4 (HAMOCC4). It is shown that the relationship between the silicic acid concentration and its silicon isotope composition is not a simple Rayleigh distillation curve. Only the Southern Ocean and the equatorial Pacific show a clear functional dependency similar to the Rayleigh distillation curve. Model results can be used to predict opal silicon isotope compositions in the sediment and constrain the use of silicon isotopes as a proxy for silicic acid utilization. Owing to the structure of the Pacific current system, it might be valid to apply a relationship between surface silicic acid concentrations and the silicon isotope signal in the equatorial Pacific sediments.