Strong archeological evidence suggests that the islands within the northern

Lagoon have been inhabited since Roman times and up to the Medieval Age. Examples of wooden waterside structures were found dating back between the first century BC and the second century AD (Canal, 1998, Canal, 2013 and Fozzati, 2013). As explained in Housley et al. (2004), due to the need for dry land suitable for building, salt marshes were enclosed and infilled to support small islands on which early settlements were built. Sites that go back to Roman imperial times are now well documented in the northern part of the lagoon. In the city of Venice itself, however, the first archeological evidence found PD-0332991 ic50 so far dates back to the 5th century AD. Only later, in the 8th to 9th century AD, did Venice start to take the character of a city (Ammerman, 2003). By the end of the 13th century, Venice was a prosperous city with a population of about 100,000 inhabitants (Housley et al., 2004). At the beginning of the 12th century, sediment delivered by the system of rivers threatened to fill the lagoon (Gatto and Carbognin, 1981). In the short term, the infilling of sediment affected the navigation and harbor activity of Venice, while in the long term,

it opened up the city to military attack by land. This situation motivated the Venetians to divert the rivers away from the lagoon, so that the sediment load of the rivers would discharge directly into the Sitaxentan Adriatic Sea. This human intervention was carried out over the next few centuries so that all the main rivers see more flowing into the lagoon were diverted by the 19th century (Favero, 1985 and Bondesan and Furlanetto, 2012). If the Venetians had not

intervened, the fate of the Venice Lagoon could have been the same as that of a lagoon in the central part of the Gulf of Lions in the south of France. This lagoon was completely filled between the 12th and 13th century (Sabatier et al., 2010). In the 19th century, significant modifications included a reduction of the number of inlets from eight to three. The depth of the remaining inlets also increased from ∼5 m to ∼15 m, with a consequent increase in tidal flow and erosive processes (Gatto and Carbognin, 1981). In the last century, dredging of major navigation channels took place in the central part of the lagoon to enhance the harbor activity. The exploitation of underground water for the industrial area of Marghera (Fig. 1) contributed to a sinking of the bottom of the basin (Carbognin, 1992 and Brambati et al., 2003). Also, the lagoon surface decreased by more than 30 percent due to activities associated with land reclamation and fish-breeding. The morphological and ecological properties of the lagoon changed dramatically: salt marsh areas decreased by more than 50 percent (from 68 km2 in 1927 to 32 km2 in 2002) and some parts of the lagoon deepened (Carniello et al., 2009, Molinaroli et al., 2009 and Sarretta et al.