@article{Dugdale_Wilkerson_2001, title={Sources and fates of silicon in the ocean: the role of diatoms in the climate and glacial cycles}, volume={65}, url={https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/688}, DOI={10.3989/scimar.2001.65s2141}, abstractNote={Diatoms with their fast growth rates and obligate requirement for Si have a unique relationship to the oceanic Si cycle with the potential for controlling the nutrient and CO<sub>2</sub> environment of large important areas of the ocean. The new production of diatoms based on both new nitrogen and Si sources is described using a Si-pump based upon the differential regeneration of the two elements. This approach, applied to the eastern equatorial Pacific, showed diatoms to respond as in a Si-limited chemostat, to the low source Si(OH)<sub>4</sub> in the Equatorial UnderCurrent. Increased Si(OH)<sub>4</sub> results in increased diatom productivity, suppression of non-diatom populations and decreased surface pCO<sub>2</sub>. The deficiency in source concentrations of Si(OH)<sub>4</sub> results from low Si(OH)<sub>4</sub>:NO<sub>3</sub> water originating in the vicinity of the Antarctic Polar Front, a consequence of the extraordinary trapping of Si by the Southern Ocean. In glacial periods this trapping is reduced several fold and likely results in increased Si(OH)<sub>4</sub> export to the north, and increased Si(OH)<sub>4</sub> production and deposition at the equatorial Pacific which can be expected to reduce surface pCO<sub>2</sub>. The connections between the eastern equatorial Pacific export production and Southern Ocean Si trapping may provide a major biogeochemical feedback system with implications for contemporary and paleoclimatology.}, number={S2}, journal={Scientia Marina}, author={Dugdale, R. C. and Wilkerson, F. P.}, year={2001}, month={Dec.}, pages={141–152} }