||P.375 left column top paragraph: "On a time scale of 10,000 years or less, the mean concentration of silicic acid in the world ocean is assumed to be constant. The total content
of silicic acid in the oceans is close to 10^17 mol of Si, and the concentration of silicic acid in the world ocean averages about 70µM. As for its distribution in the world ocean, there are marked regional differences.
In surface waters of the central gyres the concentrations are usually <2µM, but in the Antarctic, concentrations are as high as 80 to 100 µM in surface waters during winter. Deep and bottom waters are usually silicic acid-rich, with concentrations varying from 10 to 40µM in the North Atlantic to 100 to 160µM in the Antarctic, and 140 to 180µM in the North Pacific."