Diógenes Félix da Silva Costa

GEOGRAPHICAL LOCATION AND SOLAR SALT PRODUCTION

Along the Brazilian shoreline, on the northern coast of Rio Grande do Norte State Brazil) are located the largest solar saltworks of the country. The present research aims to evaluate the sustainability of the consumption of estuarine water and the area required for salt production in Brazilian solar saltworks situated along the estuary of the River Apodi-Mossoro (Rio Grande do Norte State). The analysis of the total area of production values, water volume estuary used and annual salt production was carried out, relating to the area required for this production in a solar saltwork located upstream (lower estuary) and another downstream (high estuary) in this estuary. That due to high salinity values of estuarine water upstream, the downstream saltworks require a production area three times larger than those located upstream, which obtain a production only twice superior. It was verified that the saltworks located downstream utilize the largest area and require more water volume for salt production.

Influence of ecological filters on phytoplankton communities in semi-arid solar saltern environments

ObjectiveThis study analyzed the influence of ecological filters (abiotic variables) on the phytoplankton community in hypersaline ecosystems.MethodsThe abiotic variables measured herein were: pH, water temperature, salinity, ammonium ion, total nitrogen, nitrite, nitrate, total phosphorus, and soluble reactive phosphorus. The phytoplankton community was studied for density, richness and Shannon-Wiener diversity index. Data were analyzed using analysis of variance, linear regression and Canonical correspondence analysis (CCA).ResultsIn total, 110 taxa were identified in 3 solar salterns, distributed into 9 taxonomic classes, with the predominance of Cyanobacteria (41.8%) and Bacillariophyceae (22.7%). The species Pseudanabaena galeata was the only species sampled in all saline environments. Salinity significantly influenced the richness in the three salterns, Augusto Severo (F(1,22) = 23.2, p <0.001), Francisco Menescal (F(1,22) = 50.02, p <0.001) and Santa Clara (F(1,22) = 66.33, p <0.001). The first two CCA axes explained 41.6% of total data variability, with a negative relationship with soluble reactive phosphorus for axis 2.ConclusionThe study showed the influence of the dynamics of salterns ecosystems on the phytoplankton community structure. This is associated with filters developed by the environment, where the increasing salinity, temperature and precipitation of salts influence the composition of these organisms in the ecosystem.

A multi-scale approach as a strategy for environmental analysis of hydrographic microbasins

This work is a landscape analysis of a microbasin in the Núcleo de Desertificação do Seridó and used a mapping strategy based on a multi-scale approach. The approach used land use and cover as the analysis parameter and two scales: the microbasin and the larger surrounding reservoir of the microbasin. The Shrubby Caatinga class was verified as being predominant throughout the microbasin. Based on the data collected, a comparative analysis was made of land use and cover surrounding the principal reservoir, which was identified as being predominantly the Open Shrubby Caatinga class. It was evident that even though intense anthropogenic use (removal of vegetation cover) has not occurred in the microbasin, the surrounding area of the principal reservoir has a high percentage of the Open Shrubby Caatinga, Herbaceous/Temporary Cultivation Caatinga and Exposed Soil classes, which are degraded areas that were cleared during previous years to create pastures and/or areas for temporary cultivation.

ANÁLISE FITOECOLÓGICA E ZONAÇÃO DE MANGUEZAL EM ESTUÁRIO HIPERSALINO

El manglar es un ecosistema costero de gran importancia ecologica, presentando una elevada fragilidad frente a procesos naturales y a la intervencion humana en la zona costera. El estudio en cuestion tiene por objetivo analizar la relacion entre la distribucion de las especies de mangle y los parametros geoquimicos del agua y del suelo, en el estuario del rio Apodi-Mossoro, localizado en el litoral septentrional de Rio Grande do Norte, que es un estuario hipersalino. Para la caracterizacion de la vegetacion fueron utilizados datos floristicos y estructurales de muestras tomadas a lo largo del estuario, los que fueron relacionados con datos de salinidad de agua y de suelo. Los resultados indican que la salinidad actua como factor limitante en la distribucion de las especies de mangue a lo largo del estuario, este parametro debe ser tenido en consideracion al elaborar los planes de manejo y restauracion ambiental en el estuario en analisis.