For the calculations of the Ecological Quality Ratio (EQR) of a waterbody, the ZKI values for all the replicates from the waterbody were calculated separately.
The quality status of macrozoobenthos of a waterbody was determined by comparing the EQR of macrozoobenthos quality element to the boundary values.
(1) The EQR calculation should be based on at least three grab sampling stations replicated three times.
The obtained ZKI EQR ranks correlated with the median BSPI values in the Gulf of Finland waterbodies 1 to 5 (Spearman R = -0.4, p < 0.05; Fig.
At the highest BSPI values, the EQR showed results ranging from poor to good quality in our data set.
The correlations between the EQR (on metric level and average) and the selected eutrophication variables in different water types are shown in Table 5.
Application of the EQR instead of raw data is expected to improve the indicative power of the parameters as it includes type-specific adjustment of the indicator through the use of type-specific reference conditions.
Strong relationships were identified both on raw data level and calculated, type-specific EQR level.
Results of Pearson correlation analysis between SAV indicators' EQR values and selected eutrophication variables.