C. Nalewajko et Tp. Murphy, A bioassay to assess the potential effects of sediment resuspension on phytoplankton community composition, J APPL PHYC, 10(4), 1998, pp. 341-348
A laboratory assay (SAGA or Sediment Ala;al Growth Assay) was developed to
assess the potential impact of sediment resuspension on the structure of ph
ytoplankton communities, and to evaluate the effectiveness of various sedim
ent treatments in decreasing the abundance of blue-green algae in the event
of sediment resuspension during storms. In assays with sediment from eutro
phic Akanoi Bay, Lake Biwa, Japan, 7-11 species of phytoplankton seeded fro
m the sediments grew during the 3-week assay indicating that sediment resus
pension has the potential to increase both phytoplankton biomass and specie
s diversity. Treatment of sediments with Ca(NO3)(2) substantially decreased
phytoplankton biomass (measured as chlorophyll concentration) in assays wi
th sediments from Akanoi Bay and the North Basin of Lake Biwa. Further, amo
ng various oxidation treatments of sediments, Ca(NO3)(2) was most effective
in decreasing or preventing filamentous blue-green algal growth in N- and
P-replete media. In contrast, when sediments were added to P-limited phytop
lankton dominated by green algae and diatoms, no growth of blue-green algae
occurred regardless of sediment treatment.