Abstract: Based on the data from the mangrove areas of Tieshan Bay that were collected during investigations conducted in January, May, August, and November 2008, the authors analyzed temporal and spatial variation of the nutrition in the water, and the relationship of nutritional level and distributions with environment and biological factors., The results roughly disclosed nutrient-limiting factors and their causes. The results showed Si and N concentrations were relatively high, and P concentration was low. Seasonal variation characteristics of nutritions include nutrients were generally high in spring and low in autumn and winter. Nutrition concentration and distribution were severely influenced by terrestrial input, aquaculture wastewater and litter-fall of mangrove. Terrestrial input impacted Si most heavily, less on P, and the least on N. Significance relationships were found between Si and environmental factors (23 times), between P and environmental factors (19 times), and between N and environmental factors (18 times). Primary productivity, zooplankton biomass and phytoplankton biomass were mostly influenced by N and P in spring, and by Si in autumn. P was a limiting factor in this area, N is sufficient, and Si is the highest. Nutritional level of water is eutrophic in spring, mesotrophic in summer, and oligotrophic in autumn and winter.

Key words: Tieshan Bay, mangrove, water, nutritional level, component characteristic