Abstract:

This paper studied the restrictive factors which affect the growth of phytoplankton in Dianshan Lake through the Nutrient Enrichment Bioassay,combining by two analysis methods including factorial analysis of variance and postcomparison analysis.The growth rate and the maximum average stock as well as the maximum average growth rate were affected by the nutrients including PO^3-₄P、NH³N、NO^-₃N.The results show that the concentration of PO^3-₄P could promote the growth of algae and increase the growth rate and standing stock.With the increase of PO^3-₄P concentration(0.13 ~0.53 mg/L),the promotion could be enhanced,PO^3-₄Pwas regarded as the first restrictive factors in Dianshan Lake;The promotion to algae of NO^-₃N in low concentration(291~591 mg/L) was small,while inhibition effects could be displayed in higher concentration(5.91~8.91 mg/L)；NO^-₃N could inhibit the growth of algae and the inhibition effect is enhanced with the increase of concentration(1.25~7.25 mg/L).In addition,the combination of PO^3-₄P and NO_^-3N could promote the growth of algae significantly,suggesting that the interaction effect exists between PO^3-₄P and NO^-₃N.