P. Tallberg, The magnitude of Si dissolution from diatoms at the sediment surface and its potential impact on P mobilization, ARCH HYDROB, 144(4), 1999, pp. 429-438
The magnitude of the influence of diatom-derived dissolved Si on the mobili
ty of P at the sediment-water interface was investigated in eutrophic Lake
Vesijarvi, southern Finland. The spring bloom, which consisted of small cen
tric diatoms, depleted the Si from the water column (<100 mu g l(-1)) and w
as followed by a sharp increase in the diatom numbers at the sediment surfa
ce and by a peak of dissolved Si in the sediment interstitial water. The di
atom cells disappeared from the surface sediment on a time scale of weeks (
5 % d(-1)). Calculations based on the cell numbers and on the Si deficit in
the water column indicated that the dissolution of diatoms in the sediment
surface layer may produce Si pulses high enough to influence the mobility
of P.