**1. Introduction**

The abundance and diversity of organisms in the Atacama Desert are severely limited by the high levels of desiccation and ultraviolet light [1,2]. In the Andes Mountains highlands, biodiversity is higher and plants have been used for centuries by local communities for feeding, foraging and ethnomedicine [3–8]. Microalgae and cyanobacteria are part of the Andes biodiversity but seldom acknowledged. Based on their nutritional and digestive benefits, microalgae and cyanobacteria (i.e., *Chlorella*, *Dunaliella*, *Arthrospira* and *Nostoc*) have been part of the human diet in South America, North America, Asia and Africa. Also, some species are natural resources for a variety of organic molecules with high interest to the biotechnological industry (proteins, amino acids, vitamins, polyunsaturated fatty acids, pigments) [3,4,9,10]. Edible members of the *Nostoc* genus are found in China where *Nostoc flagelliforme* has been consumed as a delicacy for centuries but its collection is prohibited today due to over-exploitation [11,12]. In South America, an indigenous foodstuff harvested in the Andes wetlands, known as Llayta, is the dry biomass of macrocolonies of a cyanobacterium from

the genus *Nostoc* (Figure 1). Llayta consumption is a practice that can be traced back to pre-Columbian times and it has been recorded in documents from the 17th century [13,14] and, in a more recent botanical report [15].

**Figure 1.** Locations, in southern Peru and northern Chile, where information on Llayta was acquired.

Thus, the genus *Nostoc* has been an old component of the human diet in South America, and it continues to be used today as a food additive in northern Chile (Arica y Parinacota and Tarapacá Regions) and in southern Peru (Tacna City) (Figure 2) [5,6,8,16–18]. However, and based on preliminary interviews, this ancient culinary legacy is disappearing and it is already unknown by the urban communities from other areas of the region; for example, at Antofagasta, the major coastal city in northern Chile, nearly 400 km south of Iquique (Figure 2).

**Figure 2.** A dry colony of Llayta obtained at a major food market in Arica, Chile. (Bar: 1 cm).

Our report provides the results of a microethnographic study conducted to learn how much people know about Llayta and their perception on this ancestral Andean ingredient, and is meant to be complementary to biochemical studies done on Llayta [4]. This work was based on the following considerations: (i) Llayta consumption is a feeding practice transmitted through generations in the rural Andean world of South America, without reports of adverse effects on human health; (ii) Llayta consumption is an old culinary legacy that is disappearing in regions of South America; (iii) Llayta is a nutritional ingredient containing essential amino acids (58% of total amino acids) and polyunsaturated fatty acids (33% total fatty acids); (iv) the prevalence of undernourishment in South America; (iv) Llayta consumption can be revitalized with appropriate educational strategies and new food derivatives can be developed from the biomass of the isolated cyanobacterium from Llayta [4,9,18,19].

We propose that this microethnographic approach will help us to explore explanations for an apparent decrease in Llayta consumption, and to provide arguments and suggestions for the revitalization of this feeding practice.

#### **2. Materials and Methods**

#### *2.1. The Microethnographic Study*

The microethnographic study on Llayta was designed to learn about the direct or indirect knowledge people have about Llayta by collecting social representations [20] from interviewing participants, including drawings prepared by children. The main expressions about Llayta were ethnographically registered and analyzed in order to explain the social worlds built by persons about their understanding of the surrounding natural, social and cultural environment [21].

#### *2.2. Sample for the Microethnographic Study*

Observations were carried out during the first half of 2014 in Tacna (Peru) and Putre (Chile) (Figure 2). Tacna is a Peruvian city located at the frontier between Peru and Chile with an active commercial exchange with Arica and Iquique, two coastal cities in Chile. Putre is a rural village at 2500 m above sea level in the Andes Range in northern Chile, close to sites where Llayta is harvested.

The participants were 19 active members of their community who were informed about the origin and purpose of the study. Their selection was based on their willingness to participate anonymously in the interviews.

The participants were 12 fourth-grade students (7 boys and 5 girls, 9–10 years old) and three middle-aged adults (three males and two females) from Putre, Chile. Participants from Tacna, Peru, were two vendors (one female and one male) working at the main food market of the city. Interviews and observations were conducted at sites normally used by the participants (street, market place, school, and hotel).

Oral interviews were conducted with all participants in order to learn their direct or indirect knowledge about Llayta (origin, physical description, uses, places where Llayta grows and is sold, its quality as food). In addition, children were also asked to draw representations of Llayta in order to evaluate how close their depictions were from the real subject.
