
%0 Journal Article
%A Kobayashi, Tsuyoshi 
%A Church, Anthony G. 
%T Role of nutrients and zooplankton grazing on phytoplankton growth in a temperate reservoir in New South Wales, Australia
%J Marine and Freshwater Research
%D 2003/09/12
%V 54
%N 5
%P 609-618
%K Ben Chifley reservoir, calanoid copepods, chlorophyll a, Daphnia, interactive effect, nitrogen, phosphorus.
%R https://doi.org/10.1071/MF02025
%U https://www.publish.csiro.au/paper/MF02025 
%X The role of nitrogen (N) and phosphorus (P) and zooplankton grazing on the growth of a phytoplankton community was investigated at different times in the Ben Chifley reservoir. In situ nutrient enrichment bioassays (n = 12) indicated that phytoplankton growth was limited by P in 33% of experiments, by both N and P in 25% of experiments and no limitation was found in 42%. The hypothesis that N or P limitation occurred when ambient N : P ratios were different from the Redfield ratio was supported in 33% of bioassay experiments, suggesting that ambient N : P ratios do not always correctly indicate if N or P is limiting. Grazing rates of the reservoir zooplankton (&#62;150 &#956;m in size) ranged from 0.023&#8211;0.199 day&#8211;1 (mean: 0.078 day&#8211;1, n = 8). The grazing efficiency, as measured by a weight-specific clearance rate, ranged from 0.049&#8211;0.743 mL &#956;g dry wt&#8211;1 day&#8211;1, and was positively correlated with the relative biomass of Daphnia in the community. The nutrient-stimulated growth of phytoplankton ranged from 0.085&#8211;1.031 day&#8211;1 (mean: 0.461 day&#8211;1, n = 10). The effect of nutrient enrichment exceeded that of zooplankton grazing in 62% of experiments. Further study is necessary to understand a qualitative effect of nutrients and zooplankton grazing on the phytoplankton community structure in the Ben Chifley reservoir. 
