Geoquímica de sedimentos e bioquímica de macrófitas em manguezais do litoral oeste do Ceará

Abstract

The red mangrove (Rhizophora mangle L.) of the studied areas represents an important biome of the Brazilian northeast coast about which little is known about the geochemical and biochemical characteristics.In this context, the research evaluated the environmental quality of the estuary of the river Ceará (area 1) and the Coreaú river (area 2), with the mangrove of the estuary of the Coreaú river, supposedly without pollutants, as a control area.Twelve random samples of rhizosphere sediments and leaves of the plants present in each area were collected and in the field physical and chemical measurements. The content of minerals was quantified using X-ray diffraction (XRD), X-ray Fluorescence (FRX) and Scanning Electron Microscopy coupled to a Dispersive Energy Spectrometer (SEM-EDS), as well as the analysis of the elements in the tissue were performed using the FRX.For biochemical characterization several methodologies were used, such as quantification of total nitrogen, analysis of enzymatic activities related to stress were extracted protein extracts of the leaves, and the extract was used in the determination for total soluble protein dosageCatalase activity (CAT), activity of Guaicol Peroxidase (GPOX), Activity of Ascorbate Peroxidase (APX), activity of Phenylalanine Ammonia Liase (PAL), Β-1,3-glucanase activity (GLU), Chitinase activity, Superoxide Dismutase activity (SOD).The contents of chlorophyll, carotenoids and phenolic compounds were also determined, aiming to correlate the substantial sediment chemistry with biochemical responses in the leaf tissues of the studied areas.In general, the data obtained show that the mangroves studied are alkaline areas, polyalins with similarities in their mineralogy differing with the presence of Cd in area 1 and absence in area 2, It was observed that biochemical responses presented greater stresses in area 1 and were significant in area 2, although fluorescence responses in sediments and leaves showed an area free of toxic elements.In addition, sampled points revealed the presence of trace elements in leaf tissue and absence in sediments, leading to a consideration for the absorption of these elements not only via soil, The presence of anthropogenic trace metals in plants may be an indicator of inorganic pollution of the environment.