BIODIVERSITA’ E STATO ECOLOGICO DI SEI LAGUNE NEL DELTA DEL PO (VENETO, ITALIA), NEL CONTESTO DELLA WATER FRAMEWORK DIRECTIVE (WFD 2000/60/EC).

The European Water Framework Directive (WFD 2000/60/EC) establishes a framework for the protection of all water (inland surface waters, transitional (Estuarine) waters, coastal waters and groundwater) which: a) prevents further deterioration, protects and enhances the status of water resources; b) promotes sustainable water use; c) aims at enhancing protection and improvement of the aquatic environment through specific measures for the progressive reduction of discharges; d) ensures the progressive reduction of pollution groundwater and prevents its further pollution; e) contributes to mitigating effect of floods and droughts. The ecological quality status of 20 stations from six Adriatic coastal lagoons was assessed using a suite of biotic indices: S (number of taxa), N (total number of individuals per sample), d (Margalef’s Index), J’ (Pielou’s Index), H’ (Shannon-Weaver diversity), AMBI, M-AMBI, BENTIX, BOPA, BITS. The analysis indicated the difficulties in deriving and using the existing indices from benthic communities in highly variable environmental conditions in coastal lagoons. Different metrics rendered different results: AMBI classified the majority of the stations as “Good/Moderate”, M-AMBI as “Good/Moderate/Poor”, BENTIX as “Poor/Bad”, BOPA as “High/Good” and BITS as “High/Good/Moderate”. Sediments are predominantly silt and clay, only in some sea mouths stations there is sand dominance. This sediment’s typology favour TOC accumulation. TOC values are comprise between 7,7 mg/g in station 2 Sacca del Canarin and 30,9 mg/g in station 4 Sacca di Scardovari. In Magni et al. (2009) were report that normal TOC values in coastal lagoons are between 10 and 28 mg/g (in Cabras, Orbetello and Venice lagoon). This is an index that show a good ecological status in Delta Po river lagoons. If we consider that AMBI and M-AMBI are indices developed for estuarine and coastal environmental, that BENTIX is developed for Mediterranean ecosystem, that BOPA not consider oligochaeta (very abundant in our lagoons) and that BITS is an index developed specifically for coastal lagoon, it possible deduce that Delta del Po lagoons are in EcoQ “Moderate-Good”, supported also by TOC data.