Istraživan je utjecaj nutrijenata na potencijal rasta kulture zelene alge Chlorella kessleri u Boroš Dravi, kanalu Lanka (Mađarska) koji u nju dotječe, te u rijeci Dravi (84 i 83 r.km), koja prima vodu Boroš Drave. Utjecaj dostupnih nutrijenata za rast alga kulture C.kessleri praćen je minijaturiziranim biotestom u laboratorijskim uvjetima te uspoređen s nutrijentima u in situ uvjetima. Najveći potencijal rasta alga C. kessleri utvrđen je u kanalu Lanka, gdje su i algama dostupne količine anorganskog dušika i o-fosfata in situ bile najveće, a najmanji u Boroš Dravi, gdje je ukupni N bio uglavnom organskog porijekla. Biotest obogaćivanja nutrijentima pokazao je na svim postajama Boroš Drave značajnu limitaciju dušikom, odnosno N i P kolimitaciju. Na postajama rijeke Drave i kanalu Lanka N i P pojedinačno i u kombinaciji nisu djelovali kao ograničavajući čimbenici na prirast alga kulture C. kessleri ukazujući na značajnije opterećenje hranjivim tvarima na tim postajama. Metoda biotesta pogodna je za praćenje trofičkih uvjeta i limitirajućih nutrijenata u plitkim vodama koje su izložene povećanom unosu nutrijenata..; 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.