Salt pan stream     Vera Cruz, Aveiro, Portugal


The marinha is not a marina. It's a series of shallow pools for evaporating salt, a system that dates back at least to the Xth century. The marinhas on the West side of Aveiro are part of a network of salt making sites along the coasts of Portugal, Spain, France and Britain. Salt is taken in from the sea at high Spring tides, and runs by gravity through a system of small sluices into pools separated by low mud banks. Over roughly a month it becomes gradually more saline, encouraging the growth of the micro algae Dunaliella salina, which turns the pools orange and reputedly gives the salt an aroma of violets.

A proof of concept for a longer term installation, the stream brings the marinhas into the performance and into conversations about environments going on in the lab. For some people in the lagoon group, it was their first time in the city. Others knew the city well and had spent time among the marshes, paths, creeks and open water that separate Aveiro from the beaches and the sea dunes. At one point there was a plan to take a solar powered boat out onto the lagoon. This was scaled back to a field trip to the group of marinhas nearest the city, followed by occasional further trips back and forth.

People could be seen scattered out across the grid of the marinha: standing or crouching on the narrow bunds: talking, taking pictures, or recording sounds. Birds with different length beaks and legs stood in the shallow water, feeding, or took flight - stilts, godwits, ringed plovers, egrets. An embankment separates the marinha from the river channel, and beyond that a series of islands with structures in different states of repair - a ruined barn on one; a new looking oyster farm with solar panels on the next. Looking back towards the city, a flyover carries traffic and trains, with pools, marsh grasses and graffiti underneath it. High sounds of waders overlay the flows of traffic.

Further out, a track runs out along the channel. Here you begin to feel you are really in the wetland. Flamingos and herons stand or lift off the mud. The fast incoming tide meets and mixes with the fresh water of the river, forming rough turbulent areas and drifting patches where the water looks thick and smooth. It's an open windy place with tall grasses, traditionally used for thatching the piles of salt on the marinhas - although the piles you saw were covered in tarpaulins held down with nets and stones.

The salt harvesting is part of the local folklore and official heritage: a figure raking salt, a mound of salt, join those in boats or vernacular dress in white line drawings woven in to the grey carpet in the Hotel Meliá Ría, where you are confined after a Covid outbreak in the group. Isn't Ría a model of car? It is the name for the lagoon, Portugal's largest wetland, on the edge of which the the marinhas are an ancient nature-culture, with some indications of a new phase, through the production of artisanal flor de sal.

The marinha is not the lagoon. It takes water from the lagoon into a holding pool - viveiro - whose name suggests that that water is direct / live from the sea - it's full of salt - it comes over the levee on the highest (Spring) tides, when solar and lunar gravity are aligned, and pours into the viveiro. After this it is distributed through the grid.

The micro habitats of the salt pans give rise to curious forms of vegetation and micro organisms. Samphyre (Crithmum maritimum and other species) shows vivid green and bright red colorations, depending on the exchange of micronutients in its rooting area. The sense of flows within the marinha as a sub region of the wider Ría environment is increased by perceptual slippages of scale: cracks in a dry pan look like satellite imagery; small aquatic plants growing in silt look like large conifers on an open landscape. The marinha is not a microcosm of the Ría. But as a modified zone on its margins, it participates in the movement of water in the Ría systems. Its shapes - essentially a grid with rounded corners - seem at once organic and technical: on Open Street Maps somebody has drawn many of the boundaries of this region in great detail, perhaps with a vector application. The marinha appears, in this way, as a kind of commentary - a productive filter on the system of the Ría.

Blurred imprints of the feet of salt workers levelling the pans are overlain with larger or smaller prints of waders. These marks remind the viewer of basic recordings, like the marks in wax cylinders, with potential to be reanimated in the form of scores for some performance to be imagined.

The sounds of the marinha are not sounds of wild nature. The salt harvest is a business and individual pans can be taken to be owned by individual households or small companies. Is it clear, however, that the salt evaporation depends on cooperative maintenance of the marinha infrastructure - the packed bunds, boards which subdivide the pools, larger dykes and sluices - as it depends on the quality of the water that feeds the viveiro.

Salt and fresh water are in constant exchange in the Ría, together with sand and sediments from the Boco River. Aveiro, 'the Venice of Portugal,' is a city of canals: water and land are clearly demarcated. This relationship becomes less defined as you walk out of the city into the marshes.

Dan Hill talked about the East Kolkata Wetlands as an alternative form of technology to a water purification plant. Wetlands can filter human waste and provide diverse habitats for water birds, invertebrates, fish, amphibians. In this sense they put the human / non human boundary directly in question, by setting up literal exchanges.

Residents of Gloriá, on the western side of the city, are called ceboleiros, with its echos of civility. We imagine them tending rows of onions. Further out on the edge of the lagoon, at Vera Cruz, people's livelihoods depend on the water. These are the cagaréus, fishers who 'shit over the edge of the boat.' A recent report confirms that many people here make an informal livelihood from fishing, shellfish collection, foraging, repairing fishing tackle, hunting on the marshes - activities that largely escape the official economy. They sit - perhaps uneasily - alongside larger scale production: aquaculture, industrial fishing, tourism.

Wetlands are hard things to engage with. There are many opportunities for wildlife to move and hide. This cryptic and elusive quality of environmental entities can make them hard to bring into the political frame. The lagoon is not a charismatic species. Its significance for the city of Aveiro as it imagines itself as a 'technical' city, is unresolved.

Imagined as a way to perform the marinhas, the live stream curiously crosses over with some kinds of 'traditional (re)enactment.' Unspectacular and leaving no long term record, it opens a transient connection with old technologies and emerging nature cultures as tools with which to think environmental futures.

Or it simply reminds us there is something out there.

. . .

The live stream forms part of the final presentation by the MTFLabs which has taken place in the city over the week. During this time, the Lagoon group worked back and forth between the salt pans and the project space in the Teatro Aveirense.

The recording is from the site of the live stream, rather than the live stream itself. It is from a dyke between two pools further off from the city than the main research site by the first set of marinhas, where the sounds of traffic on Saturday evening drowned out other sounds. This double duplicity creates an opening and invitation to imagine a re distribution of sounds as the internal combustion engine runs its course and the sense we have of the wetland shifts.

Flamingos, reeds, traffic, periurban sounds


MTFLabs 2020
City of Aveiro
Locus Sonus soundmap
Acoustic Commons network
Participants, producers, collaborators in the Lab
Dan Hill @cityofsound
Sons e memórias de Aveiro (SOMA)
Assessment of the status, development and diversification of fisheries-dependent communities - Aveiro, Portugal. Case study report, European Commission, August 2010
Lisa P. Sousa et al: Incorporation of Local Knowledge in the Identification of Ria de Aveiro Lagoon Ecosystem Services, Journal of Coastal Research, Special Issue No. 65, 2013.