My main research area is the Hg biogeochemistry in the aquatic environment. More recently I´m focused in developing my knowledge on mercury stable isotope techniques to evaluate the processes of mercury methylation/demethylation in estuarine ecosystems mainly in contaminated saltmarsh areas. I also start working with mercury stable isotopes to evaluate mercury sources in estuarine ecosystems in order to better understand the biogeochemistry processes involved in Hg cycle. However, I have also developed a substantial research program in the related field of trace- and rare earth- elements biogeochemistry in Portuguese aquatic ecosystems. Knowing their concentrations and distributions it will be possible to understand their impacts in the environment, namely their accumulation into Biota. Moreover, this knowledge also may serve to design and implement methodologies to recovery and reuse these metals to future uses, mainly in green technologies and in a wide range of industries. I have also studied the role of halophyte plants in the biogeochemistry of the REE in sediments from saltmarsh areas. This information is useful for a broader characterization of the saltmarsh systems. I start my knowledge on mercury isotope ratios and their fractionation patterns to evaluate Hg sources, processes, transport and fate in estuarine ecosystems, mainly in saltmarsh areas, evaluating at the same time, the role of saltmarsh plants in the mercury biogeochemistry cycling. I have been involved in several national and international projects through which I developed an interest and research expertise in environmental biogeochemistry, mostly in aquatic ecosystems. Consequently, I have established several productive collaborations with universities and research laboratories worldwide. My research interests by topics include: Analytical Chemistry: In the development and implementation of analytical methodologies to quantify contaminants in environmental matrices, particularly in the development of in situ strategies for sampling and routine analyses. More recently I’m particularly interested in the use of stable isotopes (mainly of mercury) to access biogeochemical processes. Contaminant Cycling in wetlands (salt-marshes): Despite this topic being related with the other below, I’m particularly interested in salt-marshes ecosystems. This type of wetlands experience constantly changing conditions and are influenced by a variety of chemical and physical variables that may affect trace elements biogeochemical processes. Moreover, the effect of salt-marsh plants in the sediment chemistry is particularly interesting. Environmental Chemistry: To understand the biogeochemical processes involved in trace element speciation, partitioning and fate and their relation with other physico-chemical variables. I’m particularly interested in early diagenesis mechanisms and how they influence other trace elements chemistry in sediments. Environmental Pollution and Ecotoxicology: To better understand the effect of pollution in living organisms particularly the physiological and ecotoxicological effects (behaviour, oxidative stress, etc). Extreme Environments: To better understand the effect of climate change and extreme events scenarios in the degradation of a) estuarine environments mostly saltmarsh areas and b) artic permafrost soils and their impact in surrounding environments, concerning the release of contaminants and organic matter. I also started extend my knowledge about possible extra-terrestrial life, by searching for organic molecules that are representative of life forms (biomarkers) that may potentially exist in icy moons of Jupiter and Saturn, using natural ice samples as a proxy of icy moons.