Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Atributos funcionais de diatomáceas perifíticas : uma abordagem para avaliação ambiental de reservatórios no semiárido

Auteur : Oliveira, Dayany Aguiar de

Université de soutenance : Universidade Estadual da Paraíba

Grade : Mestre em Ecologia e Conservação. 2020

Résumé partiel
Semi-arid reservoirs are influenced by several anthropic impacts (such as sewage discharges, hydrological, physical and chemical changes), and this interferes with the integrity of the water in these systems, often making their use for public supply, fish farming and leisure activities unfeasible. economic. Thus, it is important to evaluate the environmental quality of these systems, mainly using biological communities (peripheral diatoms), comparing metrics (density and biomass) to measure the level of environmental impact. In this context, we evaluated the environmental quality of different impact gradients based on a set of functional attributes and biological metrics (density and biomass) of peripheral diatoms. The study was carried out in four periods (June, September and December and March 2015), in the Poções, Sumé and Cordeiro reservoirs located in the state of Paraíba. Through Principal Component Analysis (PCA), the sites were classified into impact groups (less impacted, intermediate impact and severely impacted), and later related to biological metrics (density and biomass) to determine which one best characterized the gradients. Soon after, the functional attributes of the peripheral diatoms were selected and related to the environmental variables in each gradient of environmental impact. It was observed that biomass was more sensitive to variation in environmental gradients, with species segregation occurring in each gradient of environmental impact. In LD sites (less impacted sites), the species Rhopalodia gibba (28588.46 mm3cm-2) had the highest biomass, whereas in ID sites (intermediate impact sites), the most representative species was Nitzschia dissipata (102714.83 mm3cm -2), while in the SD sites (severely impacted) the largest biomass observed was of the species Gomphonema gracile (89412.84 mm3cm-2). Analyzing the size of the species, it was seen that the largest sizes had a high contribution on the LD sites, while the smallest sizes were present on the sites with the greatest environmental impact (ID and SD)

Présentation

Version intégrale (2 Mb)