This report summarizes the changes in the phytoplankton communities of seven lake basins following artificial enrichment with nitrate, phosphate and carbon. Data presented comes from the studies of Lakes 227, 304, 226 (southeast and northwest basins), 261, and 302 (north and south basins) carried out from 1969 to 1973. A total of 280 taxa were identified and a table indicates where they were found and at what season of the year.