[Sedimentation in the seasonal cycle of unicellular algae. Model analysis]

The efficiency of quick sedimentation (quicker then at normal condition) of unicellular algae at the end of seasonal cycle was studied in Okhotsk Sea. Model researches were based on the effect of competition of two algae populations. Analytical investigations of simplified variant of mathematical model and computing experiments showed that cell sedimentation and falling into the unfavorable (dark and cold) environment could be compensated by the increase in survival under these "negative" conditions. Vertical mixing of water has effect. Generally, mechanism of convective mixing is one of the factors that helps competing populations of unicellular algae to exist under conditions of changing environment.