Biogenic silica standing stock and productivity on the Mississippi-Alabama Shelf in Fall 2015

Diatoms are an important phytoplankton group in this region as they can dominate both the standing stock of phytoplankton and the rate of primary production at times. Unlike other phytoplankton groups, diatoms have an obligate requirement for silicon. Because diatoms can be important to regional primary production, there can be a strong coupling between the regional C and Si cycles. Because of this coupling, measurement of biogenic silica (bSi) production is a useful proxy to deduce the diatom-specific contribution to community rates, as silicoflagellates and radiolarians (which both use Si to build shells) are comparatively minor in biomass and grow slower than diatoms.