Biodiversidade algal e análise dos serviços ecossistêmicos em uma salina do Nordeste, Brasil

Abstract

The salt production by evaporation of sea water is one of the oldest processing activities. In several arid coastal regions, this process is carried out naturally, or artificially in interconnected tanks. The saltwork areas have high ecological value for several species of fauna and flora. These areas provide stable habitat, reproduction grounds, as well as feeding areas for various species. In the tanks where salt is produced, communities of vertebrate, invertebrate and algae (macro and micro) are comparable to hypersaline environments, presenting distribution models as a function of the salinity gradient. The present study was carried out in an industrial salt work (Salinor - Salinas do Nordeste S.A) located on the northern coast of Rio Grande do Norte. This study aimed to analyze the composition and structure of macroalgal communities in relation to the salinity gradient and to identify the potential ecosystem services associated with the study area. This research was divided into two chapters. The first chapter refers to the macroalgae characterization and distribution and environmental factors that influence the presence or absence of these organisms in a restricted saltwork area (ponds). In the second chapter, taking into account the ecological and economic importance of saltwork areas, the study was concerned with the ecosystem services analysis provided by these areas. For the macroalgae distribution study, were delimited 17 stations into the salt work area where the macroalgae are was present. A total of 32 macroalgae species were identified, of which 59% belonged to the group of red algae (Rhodophyta), 38% the green algae (Chlorophyta) and 3% the brown algae (Ochrophyta). The spatial distribution was associated to several environmental parameters. Among all the factors, salinity was considered as the principal, that determined the macroalgae composition and distribution. However, the interaction of different factors, such as depth, pH, temperature and nutrients, had a different influence on the different taxonomic groups. As for the ecosystem services analysis, provided by the saltwork biodiversity, it was possible to identify a total of 41 ecosystem services generated by the different habitats (mangrove, hypersaline tidal flats, caatinga, evaporators and crystallizers). The ecosystem services analyzed were classified in four categories (provision, support, regulation and cultural), with different functions such as food supply, biodiversity maintenance, carbon sequestration, research and ecotourism. Thus, the ecosystem services performed by saltwork areas demonstrate the importance of this areas not only in the biodiversity maintenance, but also from the economic approach.