Availability of Steelmaking Slag as a Source of Essential Elements for Phytoplankton

Abstract

Steelmaking slag contains essential elements for growth of marine phytoplankton, such as iron, phosphorus and silicon. If these elements can be available for phytoplankton in seawater, the slag can be used as a fertilizer in marine environment. In this study, growth rates of the marineplanktonic diatom Thalassiosira guillardii were determined under enrichment with the slag to confirm the availability of these elements in seawater. The medium used in the growth experiments was a modified ESAW medium, in which a powdered decarburization steelmaking slag was added. The growth response of the diatom was determined by changed in vivo chlorophyll a fluorescence. The results suggest that the decarburization steelmaking slag can be an effective source of nutrients for marine phytoplankters.