Mesocosm Experiments of Nutrient Effects on Enteromorpha prolifera Growth

Nutrient effects on Enteromorpha prolifera growth are studied in mesocosm experiments in the coastal sea area of Qingdao in June 2008.It is shown in the results from the mesocosm experiment that the wet weight biomass of Enteromorpha prolifera group supplied with nutrients becomes evidently higher than that of either the group supplied without any nutrients or the group directly sampled from the studied sea area.The daily average growth rate of the group supplied only once with a f/2 nutrient dose is 10%,that with N is 9%,and the daily average growth rate of the group directly sampled from the studied sea area is only 4%.Enteromorpha prolifera(E.prolifera for short) can rapidly absorb a large quantity of nutrients in a short time.The experimental group supplied only once with the f/2 dose(diluted from the stored solution with the f/8 concentration) can absorb 9.25 μmol·g-1·h-1 of N,and 0.63 μmol·g-1·h-1 of P in the 24 h after the nutrient solution has been added.Richer nutrients can make E.prolifera grow more rapidly.E.prolifera growth obviously depends upon nutrient type and concentration.The surroundings with multiple and rich nutrients is helpful for the E.prolifera growth.It is learnt from the comparison between NH4-N and PO4-P that the N supply is a more important role for E.prolifera growth.