The absorption of nitrogen(N) and phosphorus(P) by Hydrodictyon reticulatum was studied under laboratory conditions, and field studies were carried out simultaneously in a eutrophic reservoir in south China to assess its growth ability. Results showed that the optimal N:P ratio was 15 for its growth. Hydrodictyon reticulatum absolved phosphorus very rapidly, and almost removed phosphorus off thoroughly at various N:P ratios after growing three days. Removal rates of TN were all above 74% at variou...