Qualidade ambiental do estuário Mamanguape atrvés da bioindicação de diatomáceas (Bacillariophyta)

Abstract

In order to characterize the environmental quality and multitemporias changes Mamanguape River Estuary, remote sensing analyzes were performed (IVs) Vegetation Index and Rating and analysis of diatom community in sediments. Bordered by two protected areas, both federal liability management (CUs), the APA of the Mamanguape River Bar (APA Mamanguape) and ARIE Foz do Mamanguape River (ARIE Mamanguape), the estuary is an important conservation and refuge area for Trichechus manatus. The general hypothesis of this study were: i) conservation units, although quite pressured by anthropogenic changes have served effectively the conservation of Mamanguape estuary and, ii) the species of diatoms found along the estuary and the physicochemical factors indicating high quality environmental body aquatic. For analysis of multitemporal estuary, modifications over the years it was used vegetation and classification index. Six images were obtained corresponding to the region analyzed by Glovis website, for the years 1985, 1994, 1999, 2001, 2010 and 2016. The images were processed in the program ERDAS version 9.3 and analyzed by the NDWI indices Albedo and Classification. It was done Pearson correlation to analyze possible associations between data accumulated rainfall and analyzed indices. The NDWI and Albedo found correlation with the accumulated rainfall, different classification which showed that monoculture (previous deployment creating UC) and the tanks of shrimp (implementation in 2001) increased sharply by 2016, with a decrease in vegetation south associated with monoculture in both conservation areas, with further expansion in APA Mamanguape. For diatoms analysis, the twelve sampling points were predisposed according to the presence of human disturbances (aquaculture tanks, the presence of solid waste and the absence of these factors) at two different periods a higher flow estuary and a lower flow (drought and flood). The ebb was obtained in ANA's website through HIDROWEB software that provides the streamflow data. It was collected in situ Dissolved Oxygen (DO), temperature of water and air, electrical conductivity, water transparency (Seccli), pH, and samples of surface water for later total phosphorus analysis (Pt) and orthophosphate (Ortho-P). Sediment samples were obtained for Pt analyzes, Ortho-P, organic matter and diatoms. 47 taxa was detected diatomaceous distributed on both hydroperiods, with the region of greater richness ZM characterized in mangrove vegetation is composed of silt and clay sediment. There were no major changes of taxa in both periods analyzed, except Seminavis cf. robusta, Pleurosigma aestuari, Cocconeis sp., and Grammatophora sp. found only in the period of higher flow. The species that were present in all zones were Diploneis cf. bombus and Diploneis sp. For ZM were recorded high availability of Pt both in water and sediment and high abundance of diatom species. In conclusion: i) the classification index was more effective in understanding the different landscapes and changes in protected areas, indicating structural changes in vegetation and activity progress with economic purposes; ii) the region of mangrove (ZM) has acted as a nutrient filter and diatomaceous arising both from the continent and ocean, as well as the areas of continental shrimp tanks.