Multiple addition bioassay of Tjeukemeer water

Multiple addition bioassay of water from the eutrophic lake Tjeukemeer revealed that in 1979 from the end of May until the end of November, when the lake was dominated by Oscillatoria agardhii, N and not P was the principal factor limiting algal growth. During periods with very low concentrations of Tot-Fe_diss in the lake, chelated Fe also limited algal growth in the bioassays. The results of this study further suggested that the concentrations of trace metals have reached levels toxic to phytoplankton. Trace metals inhibited growth particularly when the lake received relatively humus-poor IJsselmeer water with a lower metal binding capacity.