Venice and Her Lagoon, The Ultimate Symbiotic Relationship

View of the lagoon from the bell tower on Torcello

Venice, more than any other city, is dependent upon and simultaneously threatened by its natural environment. Ecologists often use the word symbiosis to describe relationships between organisms. For one thousand years, Venice and her lagoon exhibited a form of mutually beneficial symbiosis; without the lagoon, Venice would never have survived, and without Venetians, the lagoon would be a historical artifact found only in old maps and in sedimentary records. The lagoon provided both sustenance and protection to Venetians for over one thousand years; meanwhile the Venetians had the foresight to divert the Brenta and Piave Rivers several centuries ago, preventing the fluvial sediment flux from turning the lagoon into a large salt flat.

The relationship between Venice and the lagoon continues, albeit under new circumstances. While Venetians remain dependent on the lagoon for food and transport, they have inadvertently damaged the ecosystem with both sewage effluent and the development of the Porto Marghera Industrial Zone on the mainland, whose waste products have contaminated much of the central lagoon. In addition, the added impact of tourism, which generates sewage, trash, and pollution from cruise ships, has been detrimental to the lagoon. Meanwhile the city continues to sink relative to the local sea level, and, therefore, the lagoon threatens the very existence of the city. In response to this escalating threat the city has developed a controversial plan to build a series of dams that can close off the lagoon during high tides, deemed the MOSE project, as its solution to the problem. MOSE and other new projects will have their own effects on the lagoon and its ecosystem by re-suspending sediments and changing circulation patterns.

Surprisingly, despite all this, large sections of the Venice Lagoon remain quite healthy. In recent years, the city has done a better job with both regulation and protection of the ecosystem. The stringent regulations in the industrial zone have reduced the amount of pollutants entering the environment. In 1994 the city reinstated a strict dredging program of the city canals, which has created a noticeable improvement in the quality of water. Many salt marshes have been reinforced with protective barriers, and some salt marshes have been built with dredge materials. Today, the lagoon remains home to dozens of species of birds such as the Sandwich Tern, many of which nest or spend the winter here. Hundreds of species of fish and shellfish remain in the lagoon, most making their home in the relatively pristine salt marshes of the north lagoon or in the area west of Pellestrina. In fact, some species survive and, nowadays even thrive, within the canals of the city of Venice.

Though conditions are improving, the lagoon continues to be threatened by the ever increasing number of tourists. These tourists can help to ensure the lagoon’s continued survival for the next millennium by disposing of their trash in proper receptacles, requesting that taxi drivers reduce speed, and therefore their wakes, in the vicinity of marshes, and flushing toilets only when necessary.

Today the lagoon is awash with sites containing evidence of Venetian interaction with the lagoon much of which can be explored during a short, private boat tour. Context’s own Science and Secrets of the Lagoon excursion gives tourists the opportunity to visit a number of these sites in the Northern Lagoon with an expert on the lagoon environment, allowing a rich discussion of the history and current safeguarding methods of the lagoon:

Forte di Sant’Andrea: Located near the Lido Inlet, Forte di Sant’Andrea was built nearly 500 years ago to offer further protection for the city against ships arriving from the Adriatic. Today it remains as excellent evidence of the “sinking” of Venice compared to mean sea levels as its cannon ramparts are approaching sea level.

Northern marshes: Many hectares of marsh exist in the northern lagoon in various stages of protection or reconstruction. These marshes are home to numerous species of birds and shellfish that can often be seen on any tour of the north lagoon.

Burano and Torcello: Though famous for silk, pastel colored houses, and a beautiful church these islands also maintain a strong fishing industry, which today offers a fantastic glimpse of the historic relationship between the lagoon and its inhabitants.

MOSE: Passing through the Lido Inlet one can begin to understand the breadth and scope of the MOSE project, the largest public works project in the history of Italy. From the dredging of the inlet and the emplacement of locks to the construction of a large island, this exciting project is well underway.

Venetian canals: The canals within the city are cleaner than they have been in many years due to strict dredging programs. Pay attention as you walk around: Look down and you might get a glimpse of the many species of algae, shellfish, and even small fish that reside here.

-John Rapaglia.  John is a coastal oceanographer obtained his PhD at the Marine Science Research Center of Stony Brook University, NY. He came to Venice in 2002 on a Fullbright Scholarship and designed Context’s Science and Secrets of the Lagoon excursion. John is currently working in Kiel, Germany, but plans on returning to Venice often.

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