Dendrometrical Structure and Physicochemical Analysis of Mangrove Sediments from the Nyong River Estuary (Cameroon, Atlantic Coast)

Abstract

Mangrove estuaries are not immune to the threats posed by climate and anthropogenic constraints on aquatic environments. In the Nyong River estuary, mangrove ecotone has capital importance for biodiversity conservation due to its localization in the Douala-Edéa protected area. For this study, seven quadrats were delimited in aim to evaluate mangrove structure and assessed his interplay with sediment and water physicochemical characteristics. The study revealed a total of 120 individuals of 4 regularly encountered species over a distance of 14 km: <i>Rhizophora racemosa, Avicennia germinans, Rhizophora harrisonii </i>and <i>Phoenix reclinata</i> palms. The marshy soils under the mangrove have Total Nitrogen percentages varying between 0.04 and 0.68%. Total Organic Carbon (from 2.20 to 8.61%) and Total Organic Matter (from 3.66 to 14.64%) contents have a similar pattern. The ratios of Carbon and Nitrogen (C/N) reflect the presence of organic matter and plant debris over a large proportion of the estuary. The ratio of Nitrogen and Phosphate (N/P) reflects the low availability of nitrogen in relation to phosphorus. The cation elements evolve on average in the order Ca<sup>2+</sup> ˃Mg<sup>2+</sup> ˃Na<sup>+</sup> ˃K<sup>+</sup>. This study provides information that would help explore linkages for future research on biogeochemical balance in mangrove sediment and their implementation.