Wetland soils, especially those under a semi-arid climate, are among the least studied soils in the tropics. The hypersaline tidal flats on the north-eastern Brazilian coast, locally named apicum, are coastal wetland ecosystems in the peripheral portions of semi-arid estuaries. Despite their great ecological importance, they have been highly impacted by anthropogenic activities. Morphological and analytical data of six soil profiles, representative of the different coastal compartments (mangroves, apicum and coastal tablelands) of the north-eastern Brazilian coast, were examined to better understand the pedogenesis of apicum soils. The hypersaline tidal flat soils were classified as Typic Fluvaquents and Typic Sulfaquents with the following main characteristics: predominance of sand fraction (62–77%); presence of high-activity clays (>24 cmolc kg–1 clay); clay fraction comprising kaolinite, illite, smectite and an interstratified smectite/illite; exchangeable complex dominated by Na+ (ESP =15%); elevated levels of salinity (electrical conductivity, EC 25–44 dS m–1); alkaline pH values (7.5–9.5). The sandy texture and quartz-dominated composition of the hypersaline, tidal flat soils indicate a pedogenesis associated with the superficial addition of mineral material. This upbuilding process would have lowered the watertable (relatively to the ground level) and decreased the flooding frequency by the tides, favouring salinisation and solonisation processes at the hypersaline tidal flats. Furthermore, the still-existing hydromorphism would have promoted the maintenance of gleisation and sulfidisation. The presence of pyrite on the hyper-saline tidal flat soils further corroborates the formation of apicum soils from/over buried mangroves.

Hypersaline tidal flats (HTFs) are transitional ecosystems commonly occurring in arid and (or) semiarid coastal regions. These ecosystems typically border mangrove forests. Hypersaline tidal flats perform important functions related to the maintenance of coastal biodiversity as well as support socioeconomic and cultural activities in local communities. Despite their importance, HTFs are rarely studied, especially with regard to the understanding of their formation and function. From the premise that the knowledge on the formation of HTF and soil contribute to the understanding of ecological relationships occurring in these ecosystems, a review is presented. Flat topography, coastal dynamics, pronounced hydric deficit, limited frequency, and duration of tidal flooding are the key factors for the formation of these coastal wetlands. The active pedogenetic processes (salinization, gleyzation, sulfidization, and bioturbation) are highly influenced by these factors and present important ecological roles, specifically in regards to carbon and nutrient dynamics. This review presents evidence for the necessity of further studies on the ecological relationships in HTFs, as well as determining the ecological connection between HTFs and other wetlands. Filling this knowledge gap is essential if we are to improve public policies and conservation laws on the protection of all coastal ecosystems.

Meireles, A.J. A, Gorayeb, A, Silva, D.R.F, Lima, G.S, 2013. Socio-environmental impacts of wind farms on the traditional communities of the western coast of Ceará, in the Brazilian Northeast The global expansion of wind power has resulted from the development of scientific research that aims to establish an energy network which minimizes the emission of pollutants derived from the combustion of fossil fuels. Ceará, in the Brazilian Northeast, has a considerable potential for the generation of environment-friendly power, due to the occurrence of strong winds on many parts of the coast and at higher elevations. Given this, the present study aimed to evaluate the socio-environmental damage caused by the installation of a wind farm on the coastal plain of the municipality of Camocim, on the western coast of the state, and to identify the consequences for the coastal environment and the traditional community of Xavier, which survives primarily on fishing, agriculture, and the extraction of natural re...