Articles | Volume 16, issue 9
Research article
02 Sep 2016
Research article |  | 02 Sep 2016

Observed and simulated trophic index (TRIX) values for the Adriatic Sea basin

Emanuela Fiori, Marco Zavatarelli, Nadia Pinardi, Cristina Mazziotti, and Carla Rita Ferrari

Abstract. The main scope of the Marine Strategy Framework Directive is to achieve good environmental status (GES) of the EU's marine waters by 2020, in order to protect the marine environment more effectively. The trophic index (TRIX) was developed by Vollenweider in 1998 for the coastal area of Emilia-Romagna (northern Adriatic Sea) and was used by the Italian legislation to characterize the trophic state of coastal waters.

We compared the TRIX index calculated from in situ data (“in situ TRIX”) with the corresponding index simulated with a coupled physics and biogeochemical numerical model (“model TRIX”) implemented in the overall Adriatic Sea. The comparison between in situ and simulated data was carried out for a data time series on the Emilia-Romagna coastal strip. This study shows the compatibility of the model with the in situ TRIX and the importance of the length of the time series in order to get robust index estimates. The model TRIX is finally calculated for the whole Adriatic Sea, showing trophic index differences across the Adriatic coastal areas.

Short summary
This study shows the capability of the numerical model in reproducing the trophic index (TRIX) calculated from in situ data. The ecosystem simulations can represent an important support for monitoring activities, allowing the use of TRIX to be extended to larger areas where in situ sampling activities are difficult to implement. The model TRIX was calculated for the whole Adriatic Sea, showing trophic differences across the Adriatic Sea.
Final-revised paper