2.08, while H
b
’ ranged from 1.14 to 3.37, at a meanfor the 2004-2005 period of 2.10 (Fig. 4). Thelowestspeciesdiversitywasobservedinbothlakesinspringwhenphytoplanktonbiomasswasthehighest, while the greatest species diversity wasnoted in summer. Larger differences in the value of this index for number and biomass were noted inLake Licheñskie, which indicates that small forms of nanoplankton occurred less abundantly than they did in Lake Œlesiñskie. There was, however, a strong