Composition and sources of sediment organic matter in a western Iberian salt marsh: Developing a novel prediction model of the bromine sedimentary pool.

Salt marshes are sensitive highly productive habitats crucial for carbon cycling. This study presents a comprehensive analysis of organic geochemical indicators and geochronology in the Mira salt marsh (SW Portugal) over eight centuries. The closely intertwined carbon and bromine (Br) biogeochemical cycles in these environments can influence the fluxes of volatile compounds such as ozone-depleting methyl bromide, emphasizing the importance of understanding sediment organic matter (OM) origin, budget, and composition in salt marshes.

Refractory organic matter in coastal salt marshes-effect on C sequestration calculations.

The age and ability of salt marshes to accumulate and sequester carbon is often assessed using the carbon isotopic signatures (ΔC and δC) of sedimentary organic matter. However, transfers of allochthonous refractory carbon (C) from the watershed to marshes would not represent new C sequestration. To better understand how refractory carbon (C) inputs affect assessments of marsh age and C sequestration, ΔC and δC of both total organic carbon (TOC), C, and non-C organic matter fractions were measured in salt marshes from four contrasting systems on the North Atlantic coast.

Coastal barrier stratigraphy for Holocene high-resolution sea-level reconstruction.

The uncertainties surrounding present and future sea-level rise have revived the debate around sea-level changes through the deglaciation and mid- to late Holocene, from which arises a need for high-quality reconstructions of regional sea level. Here, we explore the stratigraphy of a sandy barrier to identify the best sea-level indicators and provide a new sea-level reconstruction for the central Portuguese coast over the past 6.5 ka.

A 700 year record of combustion-derived pollution in northern Spain: tools to identify the Holocene/Anthropocene transition in coastal environments.

There is an uneven geographical distribution of historic records of atmospheric pollutants from SW Europe and those that exist are very limited in temporal extent. Alternative data source is required to understand temporal trends in human impacts on atmospheric pollution. Polycyclic aromatic hydrocarbons (PAHs), heavy metal content and stable Pb isotopic ratios in a sediment core from a salt marsh in northern Spain were used to reconstruct the regional history of contaminant inputs over the last 700 years.