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Horvatic J.,Odjel za Biologiju Sveucilista | Persic V.,Odjel za Biologiju Sveucilista | Kocic A.,Odjel za Biologiju Sveucilista | Santo V.,Zavod za Javno Zdravstvo | And 5 more authors.
Hrvatske Vode

The impact of nutrients on the growth potentials of the green algae Chlorella kessleri was investigated in the Boroš Drava, in the Lanka canal (Hungary) which flows into it and also in the Drava River (84 and 83 r.km), which receives waters from the Boroš Drava. The impact of the available nutrients on the growth of the algal culture C. kessleri was monitored by means of the miniaturized biotest in laboratory conditions and then compared with the nutrients in the in situ conditions. The greatest growth potential of the algae C. kessleri was determined in the Lanka canal, where the highest in situ quantities of inorganic nitrogen and O-phosphates were available to the algae, and the lowest in the Boroš Drava, in which the total N was mostly of organic origin. The biotest of nutrient enrichment showed a significant nitrogen limitation, i.e. N and P co-limitation at all stations of the Boroš Drava. At the stations of the Drava River and the Lanka canal, N and P, both individually and combined, did not act as a limiting factor on the growth of the algal culture C. kessleri, thus indicating a significant nutrient load at these stations. The biotest method is suitable for monitoring of trophic conditions and limiting nutrients in shallow waters which are exposed to increased nutrient input. Source

Horvatic J.,Odjel za Biologiju Sveucilista | Kocic A.,Odjel za Biologiju Sveucilista | Bucanac D.,Srednja Strukovna Skola | Persic V.,Odjel za Biologiju Sveucilista | Varga M.,Odjel za Biologiju Sveucilista
Hrvatske Vode

Seasonal changes of freely floating and submersed macrophytes of species in the flogbit community (As. Hydrocharidetum morsus-ranae) in the amelioration drainage canal Barbara in Baranja (northeastern Croatia) at the settlement Darda were investigated from June to September 2009 by the use of quadrant method. A total of 10 species was identified, of which the most represented was the species Hydrocharis morsus-ranae, followed by Salvinia natans and Ceratophyllum demersum. Species of the genus Hydrocharis and Salvinia were the most developed in August, and of Lemna trisulca and Myriophyllum spicatum in June and September. During summer months, the mass of fresh matter decreased in submersed species (with an increase in total chlorophyll concentrations), and increased in freely floating species. The values of nitrates indicated high status of water quality according to the Regulation on water quality standard, whereas the quantity of total phosphorus ranged from high to occasionally bad. The presence of the flogbit community in the canal Barbara is an indicator of eutrophic conditions. Source

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