Every year, the mayor of Venice celebrates the Marriage of the Sea. This ceremony, practiced since the 11th century, symbolizes the deep bond between the amphibious city and its lagoon. However, this bond is currently under threat. Years of overtourism, excessive maritime traffic, and pollution, coupled with rising sea levels and climate change, have brought the fragile lagoon to a critical point. The consequences could be devastating for one of the world's most famous destinations.
IA Index: Library of Mediterranean Knowledge
Venice would not survive without its lagoon.
22-med – November 2025
• The lagoon of Venice has lost 70% of its barenes in a century: erosion, maritime traffic, and pollution threaten a heritage ecosystem.
• Citizen projects (Respira Barena, SOS Barena) mobilize serajanti, researchers, and volunteers to restore the islets and promote carbon sequestration.
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Spanning approximately 50,000 hectares, the lagoon of Venice is a delicate ensemble of islands, canals, and barene, these small low islets covered with vegetation. It is one of the largest wetlands in the Mediterranean, recognized as a World Heritage Site by UNESCO. As a semi-closed basin, the lagoon mixes freshwater from rivers with salty seawater, creating a complex and precious ecosystem. At the heart of the lagoon lies the historic city of Venice, "founded on the waters, surrounded by waters, defended by waters instead of walls," as an edict from 1500 describes it.
This unique configuration, which allowed Venice to protect itself from enemies for centuries, now leaves the lagoon extremely vulnerable to pollution.
The daily scourge of plastic
The most visible problem remains plastic pollution, particularly from single-use plastics. Walking through the city, especially between March and September when there are more tourists, one often encounters overflowing trash bins. Waste falls to the ground and is then blown into the water by the wind or seagulls. Bottles, bags, plates, containers, and other objects end up in the canals or on the seabed day after day.
However, as serious as it is, plastic pollution is only part of the problem. The lagoon also receives wastewater from numerous industrial activities, notably from a big industrial complex, as well as from Venice, from its historic center to the mainland, and from Chioggia. Data on the presence of persistent organic pollutants is concerning. Twenty years ago, the study "The Wounded Lagoon," led by Stefano Guerzoni and Stefano Raccanelli (Libreria Editrice Cafoscarina, 2003), highlighted this chronic contamination.
Disrupted currents, a disfigured lagoon
In the southern part of the lagoon, the construction of large canals and docks for commercial and tourist ships has altered the currents. Coupled with the increase in waves caused by the constant passage of motorboats, these changes have destroyed much of the lagoon's original configuration, which was once primarily composed of barene.
This situation could worsen. At the beginning of October, Luana Zanella, the head of the environmentalist and socialist group Alleanza Verdi e Sinistra in the Italian Chamber of Deputies, questioned the Minister of the Environment, Gilberto Pichetto Fratin, about projects intended to bring large cruise ships back into the lagoon. Zanella considers these projects to be "devastating." She highlighted that the plans involve digging new canals and displacing millions of cubic meters of highly polluted mud.
"These projects go against the desire to restore the hydrogeological balance and habitat of the lagoon, which, by the way, is a UNESCO heritage site," explains Zanella. She points out that there are alternative solutions, such as docking ships outside the lagoon, that have already been evaluated positively by the Environmental Impact Assessment Commission. She adds: "Venice will only survive if we save its lagoon."
Islets in peril: a major ecological role
Time is of the essence: the area of the lagoon covered by barene has decreased by 70% over the last hundred years. This disappearance has serious consequences. In addition to hosting plants that can withstand variations in salinity, temperature, and tides, these islets serve as a habitat for over a hundred species of birds, some of which are rare.
These islets also play a significant climate-related role. They absorb and store large amounts of carbon dioxide—between thirty and fifty times more than terrestrial forests.
Residents and one artist have mobilized
In the face of this situation, local initiatives are emerging. Allison Zurfluh, a Swiss-American artist, has split her time between Venice and Switzerland for over ten years. In 2023, she co-founded the Barena Association, of which she is now president. "We aim to protect and restore the northern part of the Venice lagoon, a unique and invaluable habitat threatened by erosion due to human activities," she explains.
The association collaborates with researchers, volunteers, and local artisanal fishermen, known as serajanti, many of whom are from families that have lived in this part of the lagoon for generations.
Cleaning to revive
With the Respira Barena project, the association undertakes to clean the lagoon of the waste accumulated over the years: ghost nets, plastics, glass, metal, household appliances, abandoned motors. “It’s work that makes us happy because we see with our own eyes how the freed areas literally start to breathe again and become covered with plants and life”, says Zurfluh.
Alongside the serajanti, who know and love every inch of this part of the lagoon, she feels like she's "really making a difference."
Restoring the barene to protect Venice
The SOS Barena project draws on the expertise gained through the University of Padua's Life Vimine program. The project involves installing structures made of natural, biodegradable materials around the most threatened islets. These barriers enable marsh vegetation to regrow and protect the soil from erosion.
The association trains and pays the serajanti to perform this work. "In this way, we make a small contribution to the survival of this fishing community, which uses sustainable methods based on centuries-old traditions," emphasizes Zurfluh. "Unfortunately, their livelihood is threatened by pollution, maritime traffic, the climate crisis, and the blue crab invasion.” The goal is to install approximately 300 of these barriers by the end of 2025, which will allow the barena to sequester between 17.7 and 59.3 tons of carbon.
Thanks to initiatives like this one, as well as the commitment of various associations, NGOs, and committees, there is still hope for Venice's lagoon.
Photo credit: The Porto di Lido-San Nicolò and the lagoon of Venice ©Didier Descouens