Assessment of the ecological status of transitional waters in Sicily (Italy): First characterisation and classification according to a multiparametric approach

A 1-year cycle of observations was performed in four Sicilian transitional water systems (Oliveri-Tindari,Cape Peloro, Vendicari and Marsala) to characterise their ecological status. A panel of variables amongwhich trophic and microbial (enzyme activities, abundance of hetetrophic bacteria and of bacterial pollutionindicators) parameters, were selected. Particulate organic carbon (POC) and nitrogen (PON) andchlorophyll-a (Chl-a) contents defined the trophic state, while microbial hydrolysis rates and abundancegave insights on microbial community efficiency in organic matter transformation and on allochthonousinputs. To classify the trophic state of examined waters, the synthetic trophic state index (TRIX) was calculated.Microbial hydrolysis rates correlated positively with POC and Chl-a, which increased along the eutrophicationgradient. The significant relationships among TRIX, trophic and microbial parameters suggestedthe use of leucine aminopeptidase, alkaline phosphatase and POC as suitable parameters to implementthe Water Framework Directive when assessing the ecological status of transitional water systems.