Modern pollen and non-pollen palynomorph assemblages of salt marsh and subtidal environments from the Ría de Vigo (NW Iberia)

Pollen and non-pollen assemblages were studied in 40 surface samples obtained from different sedimentary environments of two salt marshes and the subtidal area in the Ría de Vigo (NW Iberia). The percentage and concentration distributions of pollen, dinocysts and other non-pollen palynomorphs (NPP), which include fungal and algal spores, were analyzed by numerical methods. Our purpose was to determine whether the studied environments have a characteristic pollen fingerprint. Also, we aimed to assess how the specific abiotic conditions and the local/regional vegetation of the environments studied influence the surface pollen pattern.A cluster analysis grouped the samples into six pollen classes corresponding to marsh zones with different local vegetation and abiotic conditions. A principal component analysis supported the classification and showed that most of the environments studied had characteristic pollen patterns. The best differentiated ones were those of the low marsh dominated by Halimione portulacoides (mainly characterized by the local pollen predominance) and the subtidal area (characterized by high percentages of dinocysts and regional pollen, particularly of Pinus and Erica). A gradient was also evidenced in the distribution of some palynomorphs and may respond to abiotic factors, such as altitude above the mean sea level and distance from the pollen sources.Here, we provide new data on the relationship between modern palynomorphs and coastal habitats from the Ría de Vigo that could be useful for interpreting ancient environments by comparing the modern pollen analogues with the fossil data. This study may have implications for paleoenvironmental reconstructions in coastal and shallow marine environments, particularly in those of NW Iberia.