Fig. 8. The dependences of relative abundances in a four-species culture on the initial environmental nitrogen to phosphorus ratio. 1 — Ch. vulgaris (the demands ratio q^N/q^P = 8); 2 — S. obliquus (q^N/q^P = 13); 3 — S. quadricauda (q^N/q^P = 19); 4 — Ankistrodesmus sp. (q^N/q^P=25).