Venetian Lagoon

TheVenetian Lagoon(Italian:Laguna di Venezia;Venetian:Łaguna de Venesia) is an enclosed bay of theAdriatic Sea, innorthern Italy, in which the city ofVeniceis situated. Its name in theItalianandVenetian languages,Laguna Veneta(cognate of Latinlacus'lake'), has provided the English name for an enclosed, shallowembaymentof salt water: alagoon.
The Venetian Lagoon stretches from theRiver Silein the north to theBrentain the south, with a surface area of around 550 square kilometres (212 square miles). It is around 8% land, including Venice itself and many smaller islands. About 11% is permanently covered by open water, orcanals, as the network of dredged channels are called, while around 80% consists ofmud flats, tidal shallows andsalt marshes. The Lagoon is the largestwetlandin theMediterranean Basin.
It is connected to theAdriatic Seaby threeinlets:Lido,MalamoccoandChioggia. Situated at one end of a largely enclosed sea, the lagoon is subject to large variations in its water level.The most extreme are thespring tidesknown as theacqua alta(Italian for "high water"), which regularly flood much of Venice.
The nearbyMarano-Grado Lagoon, with a surface area of around 160 square kilometres (62 square miles), is the northernmost lagoon in the Adriatic Sea and is sometimes called the "twin sister of the Venice lagoon".
The Lagoon of Venice is the most important survivor of a system ofestuarinelagoons that in Roman times extended fromRavennanorth toTrieste. In the fifth and sixth centuries, the Lagoon gave security to Romanised people fleeing invaders (mostly theHunsand theLombards). Later, it provided naturally protected conditions for the growth of theVenetian Republicand itsmaritime empire. It still provides a base for aseaport, theVenetian Arsenal, and forfishing, as well as a limited amount ofhuntingand the newer industry offish farming.
The Lagoon was formed about six to seven thousand years ago, when themarine transgressionfollowing theIce Ageflooded the upper Adriatic coastal plain.Deposition of river sediments compensated for the sinking coastal plain, and coastwise drift from the mouth of thePotended to form sandbars that closed tidal inlets.
The present aspect of the Lagoon is the result of human intervention. In the fifteenth and sixteenth centuries, Venetian hydraulic projects designed to prevent the lagoon from turning into a marsh reversed the natural evolution of the Lagoon. Pumping ofaquiferssince the nineteenth century has increasedsubsidence. Many of the Lagoon's islands had originally been marshy, but a gradual drainage programme rendered them habitable. Many of the smaller islands are entirely artificial, while some areas around the seaport of theMestreare also reclaimed islands. The remaining islands—-including those of the coastal strip (Lido,PellestrinaandTreporti)—-are essentiallydunes.
Venice Lagoon has been inhabited from the most ancient times, but it was only during and after thefall of the Western Roman Empirethat people coming from theVenetian mainlandsettled in numbers large enough to found the city ofVenice. Today, the main cities inside the lagoon are Venice (at the centre of it) andChioggia(at the southern inlet);Lido di VeneziaandPellestrinaare inhabited as well, but they are considered part of Venice. However, most of the inhabitants of Venice, as well as its economic core (its airport and harbor), are on the western border of the lagoon, around the former towns ofMestreandMarghera. There are also two towns at the northern end of the lagoon:Jesolo(a famous sea resort) andCavallino-Treporti.
Bottlenose dolphinsoccasionally enter the lagoon, possibly for feeding.
The level of pollution in the lagoon has long been a concern.The largephytoplanktonandmacroalgaeblooms in the late 1980s proved particularly devastating.Researchers have identified the lagoon as one of the primary areas where non-indigenous species are introduced into theMediterranean Sea.
Cruise ships crossing the Venetian Lagoon have contributed to air pollution, surface-water pollution, decreased water quality, erosion, and loss of landscape.
From 1987 to 2003, the Venice Lagoon was harmed by a reduction in nutrient inputs and by macroalgal biomasses caused byclimate change, and by changes in the concentration and distribution ofnitrogen, organicphosphorusandorganic carbonin the upper sediments. At the same time, however, theseagrassesstarted a natural process of recolonization, helping to partially restore the pristine conditions of the marine ecosystem.
The Venice Lagoon is mostly included in theMetropolitan City of Venice, but the south-western area is part of theProvince of Padua.
The largest islands or archipelagos by area, excluding coastal reclaimed land and the coastalbarrier beaches:
Other inhabited islands include: