Test of Resource Competition Theory Between Microalga and Macroalga Under Phosphate Limitation

摘要

Short-term batch cultures were used to measure the phosphate-dependent growth kinetics for a marine microalga, Tetraselmis subcordifarmis (Wille) Hazen, and a marine macroalga, Ulva pertusa Kjellm. Results were fitted to the Monod model. U. pertusa had a lower half-saturation constant and maximum growth rate, which were 0.016 μmol/L and 0.16 d~(-1) respectively, while the growth kinetics of T. subcordiformis were 0.021 μmol/L and 0.83 d~(-1). Long-term semicontinuous nutrient competition experiments were performed between T. subcordifarmis and U. pertusa under phosphate limitation in laboratory. Loss rates were manipulated to get the same or different resource requirement values (R~*) of the two species. Comparison between the theoretical predictions derived from Monod kinetics and the outcome of competition experiments indicated that the Monod model could predict the results only when the R~* values of the two species were significantly different, and T. subcordifarmis displaced U. pertusa when they had the same resource requirements. The Monod model can only partly predict the competition results between mieroalga and macroalga.