No difference in the proportion of recruited cells was observed before and after the usual overwintering period,suggesting that the annual benthic overwintering does not impair the ability of Microcystis to inoculate the water column in the fol-lowing spring.However,in the oldest population,the proportion of recruited cells were lower under all the experimental conditions tested,indicating a decrease in the ability of older benthic population of Microcystis to the recruitment process.