Original paper

Occurrence, coexistence and competition of Limnothrix redekei and Planktothrix agardhii: analysis of Danish-Estonian lake database

Nõges, Peeter; Ott, Ingmar


The occurrence and coexistence of Planktothrix agardhii and Limnothrix, redekei were studied based on pooled long-term databases of Danish and Estonian lakes. P. agardhii was more common in Denmark and L. redekei in Estonian lakes. Most of the variables, which mean values differed while grouped by species (Secchi depth, Chl a, light attenuation coefficient, phosphates and total P contents, N/P ratio, pH) showed a higher trophic status associated with the occurrence of P. agardhii compared with L. redekei. The analysis showed that the higher water transparency in "redekei" lakes could not be the factor explaining the success of L. redekei but was rather a phenomenon accompanying the lower phosphorus level. The often observed later invasion of L. redekei into lakes inhabited by P. agardhii cannot be explained by differences in the species nutrient requirements. L. rededkei developed seasonally earlier than P. agardhii but still signs of competition could be revealed in cases of their mass occurence. For L. redekei the coexistence with P. agardhii was more common than the occurrence without P. agardhii.


planktothrix agardhiilimnothrix redekeieutrophicationshallow lakes