Transport and distribution of fluvial pollen in the northern portion of Guanabara Bay, southeastern Brazil: A paleoenvironmental tool

Paleovegetation studies require understanding the relationship between vegetation dynamics and the processes controlling pollen deposition. This article investigates the mechanisms of pollen deposition and the associated vegetation patterns within the hydrographic basin of Guanabara Bay, a region of considerable ecological diversity and complexity situated in southeastern Brazil. Fifty-six surface sediment samples were collected from several Guanabara Bay hydrographic basin locations. Palynological analysis was used together with multivariate methods, such as Non-Metric Multidimensional Scaling (NMDS) and cluster analysis, were used to identify patterns of similarity between the samples. Furthermore, Statistical tests, including ANOSIM, were employed to assess significant differences in taxon composition among the study areas. The palynological analysis identified a high frequency of shrub and herbaceous pollen types, mainly represented by Poaceae. The mangrove vegetation, represented by Avicennia and Rhizophora, was recorded primarily on samples near the intertidal zone. This research contributes to a better understanding of pollen-vegetation relationships and the mechanisms governing pollen transport within estuarine sediments. The findings provide valuable insights into the potential pollen sources in Guanabara Bay, aiding in assessing ecological changes and environmental preservation efforts. Further studies are necessary to expand the knowledge of pollen transport dynamics and vegetation patterns in large basins with complex vectors, such as the Guanabara Bay watershed.