Geochemical and micropalaeontological characteristics of saltmarshes in the Estero de Urias coastal lagoon, Gulf of California, Mexico

The elemental composition of sediments and the distribution and abundance of microfossils were analyzed in two saltmarsh areas of the Estero de Urias coastal lagoon (Gulf of California, Mexico) to determine the current environmental characteristics of this restricted marine environment. Enrichment by metals (particularly Cu, Ni, Pb and 2n) was detected likely due to the combustion of fuels related to the harbour activities and the thermoelectric station adjacent to the coastal lagoon. Benthic foraminifera and ostracods showed a relationship with topographic elevation above mean sea level, with very few species constituting the assemblages. No relationship was observed between sediment pollution and the presence or abundance of individuals and tests. The combined approach between geochemistry and micropalaeontology is considered suitable for the identification of possible human impacts and sea-level variations from historical and Holocene sedimentary sequences of this coastal region.