Figure 7. The effect of diatom detritus on the release of phosphate from samples incubated in the dark under laboratory conditions. Control = estuary water with no sediment; + diatoms = estuary water plus diatom detritus; Sediment = estuary water above a sediment core; Sediment + diatom = estuary water, sediment core, and added diatom detritus. (Data of Lukatelich.¹)