Dantas Dos Santos

This book focuses on oceanographic research carried out in the Formoso River estuary (08 39’S/35 10’W) and aimed to understand the seasonal dynamics of sedimentological and geochemical processes in the estuary. A total of 48 sediment samples were collected in September 2014 and March 2015. Particle size, geochemical analyses were carried out: MOT, CaCO3, TOC, PT, PO and PI and the C/P elemental ratio was calculated. The sediments were predominantly sandy and poorly sorted at both times. The gravel fraction accounted for little of the total samples and the largest proportion of the mud fraction occurred upstream of the estuary.As for the C/P ratio, there were dominant values above 300, indicating the continental origin of the organic matter. Seasonally, there was an increase in the parameters granulation, degree of selection and TOC, and a decrease in the parameters CaCO3, MOT, PT, PO and PI. It can be seen that the estuary is subject to the anthropogenic actions that surround it. It has shown anomalies in the spatial distribution of organic matter in the areas adjacent to the shrimp ponds and under the influence of sewage from the region’s urban areas.