The following description is from a final report for an NSF OCE award provided by the dataset contact.

As biomass increases, steady state Fe prime invariably changes; this was minimized to less than 5% under all Fe conditions by making modifications to the Aquil recipe. In addition, excursions in media pH (which also change Fe' prime) were minimized by acclimating cells to pH buffer (EPPS) treated with chelex-100 resin.

A maximum of 750 pmol/L Fe prime is assumed because of Fe hydroxide precipitation, but for simplicity, the investigators report the results as Fe prime even at concentrations exceeding this maximum. Steady-state uptake rates for several diatoms continue to increase with increasing total Fe within the region of Fe hydroxide precipitation (Sunda and Huntsman 1995; Mar Chem 50:189).

In T. pseudonana experiment E, addition of Fe to remaining low Fe cultures after diel sampling resulted in an increase in growth rate after 24 h, confirming growth rate limitation by Fe. The similar Fv/Fm values under low and high Fe are consistent with the data of Price 2005 (Limnol. Oceanogr. 50:1159).

In P. tricornutum experiment C, the pH buffer stock solution was not properly buffered before use in cultures. While these particular experiments will need to be repeated, these samples may be useful for comparing the diatom transcriptomes during holocene and anthropocene conditions, as these pH values are consistent with predicted values for 2100 (Gruber et al. 1996 Global Biogeochemical Cycles).