Atlantis in laguna?? Discover the lagoon along the Voga Longa route in May

From thriving lagoon settlements to lonely bird sanctuaries in the north-eastern lagoon: This is a blog post with a lack of pictures of what I am describing - because what is left is the calm lagoon waters, and the islands have disappeared beneath. This is why lagoon archeology is a big topic here with us... just look at the website Archeo-Sub. With the upcoming boat events in May, it is good to know what one would have seen along the boat course five hundred years ago, and the difference is very touching and stark - because today there is - nothing left. This is the story of the island groups of Ammiana, Santa Cristina and Costanziaca.
A famous view towards Torcello: from the island of Sant'Ariano
With the boats of Voga Longa passing near this area of the lagoon, aptly named laguna morta (where less sea water exchange takes place), those islands I am referring to would have been quite a sight.
Why, there is an Atlantis effect in laguna - slight though, I mean that seismic activity is present in the lagoon, as is described in this article by La Nuova Venezia. Take the example of the island of Malamocco, which was flooded and destroyed by a seaquake (maremoto) earthquake (just like the mythical island state of Atlantis was said to have been) around the years 1106 and 1117 AD. 
Usually, simply erosion is the reason for islands disappearing, in particular if they are located near the natural lagoon channels (where the river mouths transport not only debris but are also characterized by strong currents of water that erode the fundaments and banks of the islands in their wake. Sometimes the Venetian  Republic authority Magistato alle acque succeeded in safeguarding the islands, sometimes not, as you will see. So this is why the islands in the lagoon are usually fortified by thick red brick walls ...
Laguna nord-orientale, view towards Burano and Torcello
Island of San Michele (cemetary) with re-inforced banks to withstand erosion, as the main channel from Murano towards Venice is passing nearby ...
Sometimes there are insiduous currents in the lagoon, and the channels are marked by the bricole (usually home to gabbiani reali - sea gulls)
Isola La Certosa - also fortified by these typical red brick walls
Groviglio di bricole - there are waterways that need to be caved out regularly to be deep enough for boats to pass !
As May is the month when two of the most renowned boating events take place in the lagoon (Festa della Sensa, Voga Longa), why not take a look a bit further ahead into the churning waters of the lagoon, off the boat event routes.
If you would like to learn more about the islands that are circled by this percorso, I have a book recommendation for you, if you speak Italian: a book that I remember on my grandmother's bookshelf ever since. It is not one of the glossy ones, often very beautifully bound and illustrated, but it is a very elegant one, with a light brown cover including black and white photos and illustrations, by Giannina Piamonte, published in 1975. This book is a favorite with us because it is a trove of information on the lagoon non reperibile in questi giorni: Litorali ed isole.
The book comes with two detailed maps of the lagoon first published in 1838, taken from the four-book series "Il fiore di Venezia" (guess, we have that too in our library...), and is divided into four sections (north-west, north-east, south-east and south). And it is here that I have had ample opportunity to learn about these island groups located between Torcello and Lio Piccolo. 
Voga Longa journey: passing by the islands Certosa and Sant'Erasmo, Burrano and returning to Murano and to Venice ... more at the homepage Voga Longa. And the islands I am mentioning here would have been in the ´upper right corner of the picture above.
The island groups of Ammiana and Costanziaca were settled by the refugees from Altino in the fifth century AD, and it was there that the inhabitants of Iesolo and Eraclea sought refuge as well. Seven churches were built on the island, but all have been destroyed by the sea, and were given up in 1442 when the monks moved to Venice, to the convent of SS Filipo e Giacomo (Sant'Apollonia). From Ammiana, actually a few canals and dossi (small elevations), like the Motta di San Lorenzo are left. You can read more on a website on Medevial archeology which the link above leads to.
Ammiana - lagoon archeology
Ammiana and Costanziaca - where they should have been ... in the far back, you can see the leaning belltower of Burano
Long before the islands became eroded by the currents, they became ever more often flooded by the tides. This ambiente attracted mosquitos and other amphibious animals, often snakes, making the territory of the often half-flooded and swampy islands malsane "unhealthy". So the inhabitants left the islands to decay and finally disappear amongst the waves, often as a whole but often only in part, with the remaining parts having been transformed into what is now called barene and velme - that is, salt-loving plants (piante alofile) have settled and represent the only vegetation in many flood-exposed parts of the lagoon.
So this it what you should know about a lagoon area looking rather unkempt and empty, when you come here and pass nearby, maybe on a visit to Burano or Torcello... so today this part of the lagoon has become a natural bird paradise or sanctuary, so to say, with nature taking us back to the aspects of the beginning of life in the lagoon.
Undisturbed home to waterfowl
Book "Uccelli  in Laguna", including a link to the "Atlas of birdlife in the lagoon of Venice"