Dissolution Dominates Silica Cycling in a Shelf Sea Autumn Bloom

Abstract

Small marine microalgae called diatoms are responsible for significant levels of primary production in support of marine ecosystems. Diatom cells are formed from silica dissolved in seawater; however, diatom cells may also readily dissolve in seawater. Observationsof silica uptake and dissolution during the autumn period of enhanced microalgal productivity in a shelf seafound a nonliving detrital pool of diatomaceous material, which was dissolving faster than the few diatomspresent were making new cells. These observations highlight that certain periods of the year may be associated with rapid rates of dissolution and hence are important for recycling of material prior to the winter period when nutrient budgets in the water-column are set for the following year.