Testing the silica hypothesis: Measuring how silicon dissolution varies with temperature, dissolved organic carbon concentration, and aluminum concentration

I determined the amount and rate of silica dissolution from dust. X-Ray fluorescence measurements showed that approximately 60% of dust is silica, three times higher than values published by Gatz and Prospero (1996). Dissolution experiments show that 20--25% of the silica present in dust dissolves and becomes available for biological uptake, contrasting Wollast and Chou's (1985) 5--10% value.; These results suggest that the Aeolian Si fluxes to the ocean are greater than previously thought. Treguer (1995) estimated that wind delivers 0.5 teramoles Si/year to the ocean today. My estimates range from 7.6 to 10.6 teramoles Si/year. During glacial times, I estimate that the flux of Si to the ocean ranged from 12.6 to 23.1 teramoles Si/year. This increased flux of Si to the ocean during glacial times could have increased diatom population enough to lower atmospheric carbon dioxide levels by 80 ppm (Harrison, 2000).