Effect of seasonality and estuarine waters on the phytoplankton of the Guamá River (Belém, Amazon, Brazil).

This study aimed to analyze the application of the Phytoplankton Community Index-PCI and Functional Groups-FG in determining the water quality of the Guamá River (Pará, Amazônia, Brazil). Samplings occurred monthly for analyses of phytoplankton and physical and chemical parameters, for two years, at the station where water was collected for human supply consumption. Seasonality influenced electrical conductivity, total suspended solids, dissolved oxygen, transparency, winds, true color, and N-ammoniacal. The ebb tide showed high turbidity and suspended solids. The density varied seasonally with the highest values occurring in September and December (61.1 ind mL-1 and 60.2 ind mL-1, respectively). Chlorophyll-a was more elevated in December (21.0 ± 4.7 µg L-1) and chlorophyll-c higher in relation to clorophyll- b indicated the dominance of diatoms. Functional Group P prevailed in the study months. Through the PCI índex the waters of Guamá River varied from reasonable to excellent and the TSI ranged from oligo to mesotrophic. The use of Functional Groups proved to be a promising tool in the determination of water quality since it covered the most abundant species in the Environment, but the PCI is not adequate to characterize Amazonian white-waters rivers, which have diatoms as the leading dominant group.

Bioacumulation of trace elements in the crab Ucides cordatus (Linnaeus, 1763) from the macrotidal mangrove coast region of the Brazilian Amazon.

In this study, trace element concentrations were measured in chelipod and gill samples of the crab U. cordatus by induced coupled plasma optical emission spectrometry (ICP OES). The element average concentrations between the structures were statistically compared. Gill concentrations of Cu and Zn were higher in female crabs, while in chelipods, Pb concentrations were higher in males. The concentration of Zn in crabs from Curuçá City were higher than the recommended by health agencies, but the provisional tolerable daily intake value (PTDI), for Zn and Cu, showed only 10 and 23% contribution, respectively. The bioaccumulation factor was higher than 1 for Cu (gills and chelipods) and Zn (only for chelipods), which suggests bioaccumulation for these elements. Further metallomic and oxidative stress analyses are suggested, in order to evaluate possible protein and/or enzymatic biomarkers of toxicity.