I would like to ask the authors to revise the paper following the points raised the referees. One question might require additional elaboration in the final version. The authors and the referee #2 have contrasting opinions concerning the presence of grooundwater in the lagoon. My suggestion is that the referee's view (no groundwater inflows - two component mixing) should be explicitly presented as an alternative hypothesis together with your refutation of it. Furthermore, the paper says little about the hydrogeology of the study area. Is there any hydrogeological evidence of subsurface inflow into the lagoon which might be used to support your argumentation?