Stable patterns in size structure of a phytoplankton species of Lake Kinneret

The aim of the study was a search for typical structure patterns of phytoplankton assemblages, based on the long-term dynamics analysis. As a test case we used the interannual phytoplankton variability of Lake Kinneret (Israel). The dominant phytoplankton species (Peridinium gatunense) structure was presented as the frequency-weighted taxonomic size spectrum (TSS) which describes the size distribution of the operational taxonomic unit (OTUj) occurrence frequencies. Using 24 years monitoring data, the TSS annual patterns of P. gatunense were compared. Typical persistent TSS patterns were evident even during years of pronounced deviations from the typical patterns of phytoplankton biomass dynamics and species composition. By correlation analysis, hierarchical cluster analysis and ANOVA the TSS variability was quantified and compared. While the TSS general shape was almost constant, its amplitude variations allowed us to distinguish between three levels of annual bloom intensity.