engleski

Seagrass Zostera noltei as bioindicator of ecological status of Croatian transitional waters

During the implementation phase of the EU Water Framework Directive, CYMOX method (Cymodocea nodosaindex) was used to determine the ecological status of Croatian transitional waters. During the monitoring program, it was found that C. nodosadoes not sufficiently inhabit some of Croatian transitional waters and that it can not be used as indicator species for the whole area. In contrast, seagrass Zostera noltei is very abundant in almost all Croatian transitional waters therefore slightly modified CYMOX method was applied on this species. In total, 9 meadows from different transitional waters located along entire Croatian coast, were analyzed. For calculation of ecological quality ratio (EQR) values, 12 parameters were considered: total leaf weight, root weight ratio, and percentage of N, ratio of isotope 15N, ratio of isotope 34S, amounts of Cu, Cd, Zn, Ni, Mn, Fe and Pb in rhizomes. Obtained EQR values showed that 3 meadows were in bad ecological status, 4 in good and 2 were in very good ecological status. Significant correlation (R2=0.87 ; p<0.01) between obtained EQR values and measured abiotic parameters (NO3-, NO2-, NH3, PO43-, SiO42-, organic matter in sediment) at sampling location was found. The obtained results show and suggest that seagrass Z. noltei could be used as a bioindicator of ecological status of transitional waters in Croatia.

Zostera noltei; ecological status

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