Naslov
Bioassay method in the trophic evaluation of a wetland area-case study in the Danubian region (1426-1388 r.km)

Autori
Peršić, Vesna ; Horvatić, Janja ; Mihaljević, Melita

Izvornik
Periodicum biologorum (0031-5362) 107 (2005), 3; 293-298

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
bioassay; Chlorella kessleri; trophic level; Danube wetlands

Sažetak
Background and Purpose: The primary objective of this investigation was to examine the effects of nutrient enrichment, by using miniaturized algal bioassay, on the growth of the unicellular green alga C. kessleri in order to make a comparative evaluation of the trophic level and productivity of water ecosystems of the Danube (1426-1388 r.km) and its wetland areas. Comparative algal growth potential (AGP) of original water samples was done in inoculum concentrations of 400.000 and 800.000 cells/ml of C. kessleri. Materials and Methods: Water samples were collected on September 12th and November 14th 2002, and March 27th 2003 at 13 localities in the Danubian region. The miniaturized bioassay method was used to establish the algal growth potential of C. kessleri. Results: The results of AGP in nutrient enrichment bioassay indicate that algal growth was generally limited by nitrogen. Based on the results of chemical analysis the highest nitrate concentrations were measured at locations of the Danube main-arm and the smallest nitrate concentrations were measured at locations of the flood protected area of Kopački Rit Nature Park and the Stara Drava dead arm. Ratio of total nitrogen to total phosphorus (N/P) varied in September from 3.945 to 18.268, in November from 0.747 to 8.97 and in March from 0.670 to 14.176. According to AGP results (46.566 - 100.288 mg/l DW), the waters in the wetland area of the Danube region were oligomesotrophic to mesotrophic and highly productive. Conclusions The bioassay method is more suitable for the trophic evaluation with inoculum concentration of 800.000 cell/ml of Chlorella kessleri than with inoculum of 400.000 cell/ml. Nitrogen was the limiting nutrient for growth potential of C. kessleri in 79% of samples and phosphorus in only 2% of the samples, while in 19% of samples there was no significant influence of added nutrients on the growth of C. kessleri. A greater trophic potential of the investigated localities was established on the basis of the N/P ratio than on the basis of the AGP of C.kessleri.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA