Phytoplankton and Macrophytes in Bulgarian Standing Water Bodies.

The current status of a lake can be evaluated via monitoring based on biological quality elements. Reference aquatic flora communities reflect pristine situations that exist or would exist with no or very minor disturbances from anthropogenic pressure. Phytoplankton and macrophytes were studied in 10 national lake types (L1, L3, L4, L5, L7, L8, L11, L12, L13, L17). Type-specific taxa and groups character in reference and near reference conditions were described. Abiotic parameters (water chemistry) were also discussed. Descriptor species from 25 FGs were registered in phytoplankton communities in lakes in reference and near reference conditions. Dinoflagellates (L0) cryptomonads (Y) and various benthic/periphytic taxa (MP) were distributed in almost all lake types. Character descriptor species and FGs were reported for lake types L1 and L5. Motile mixotrophic dinoflagellates (L0) and cryptomonads (Y) had highest relative biovolume in ultraoligotrophic alpine lakes (L1) due to their ability to utilize effectively scarce trophic resources. Motile euglenoids (W1, W2), small-celled colonial Cyanobacteria (K), green algae and small cryptomonads (X1, X2), coccal green algae (J) and meroplanctonic diatoms (MP) dominated phytoplankton community in riverine marshes (L5). Recorded FGs from natural lakes were also common in and their analog among heavy modified water bodies: shallow lowland reservoirs L17. Phytoplankton communities of L13 (small and medium-size semi-mountain reservoirs in the Eastern Balkans) were more similar with those of L11 (large deep reservoirs) and mountain L1, L3. Further surveys are needed in order to classify specific features of phytoplankton communities in L3, L4, L7, L11 and L12. [ABSTRACT FROM AUTHOR]