Notes and comments:

1. The terms "biogenic silica production" and "Si uptake" are synonymous for the data reported here. Thus "rho" also represents as the rate of Si uptake and "Vb" represents the specific rate of Si uptake.

2. All reported rates are derived from the measured 32Si activity in particulate matter recovered from incubated samples, based on triplicate, 40-minute liquid scintillation counts. Counting precision was <1% in almost all cases. The overall uncertainty in "rho" and "Vb" can only be estimated, but it is almost certainly no less than 5%.

3. Silica measurements were made only on APFZ cruises. There were no corresponding measurements in the Ross Sea.