João Canário

João Canário
University of Lisbon | UL · Instituto Superior Técnico

PhD

About

154
Publications
27,745
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,858
Citations
Introduction
My main research interests are on the field of environmental chemistry mainly in the fate and biogeochemistry of key pollutants in the environment. At the present time I'm at CQE of IST focusing my work in biogeochemical cycle of contaminants in Antarctica and in understanding the changes in contaminant, carbon and sulfur cycles in the Arctic melting permafrost due to climate warming. I'm also starting to look on the ecotoxicological effects of key pollutants input in the polar living organisms
Additional affiliations
January 2011 - December 2012
University of Lisbon
September 2007 - October 2007
Acadia University
Position
  • Invited Researcher
January 2007 - present
Environment Canada
Education
September 2017 - September 2017
Instituto Superior Técnico
Field of study
  • Chemistry
September 2000 - October 2004
Universidade NOVA de Lisboa
Field of study
  • Environmental Sciences (Environmental Chemistry)
September 1998 - June 2000
Universidade NOVA de Lisboa
Field of study
  • Marine Sciences

Publications

Publications (154)
Preprint
Full-text available
Thermokarst lakes and ponds are a common landscape feature resulting from permafrost thaw, but their intense greenhouse gas emissions are still poorly constrained as a feedback mechanism for global warming because of their diversity, abundance and remoteness. Thermokarst waterbodies may be small and optically diverse, posing specific challenges for...
Article
Current knowledge of the processes that shape prokaryotic community assembly in sea ice across polar ecosystems is scarce. Here, we coupled culture-dependent (bacterial isolation on R2A medium) and culture-independent (high-throughput 16S rRNA gene sequencing) approaches to provide the first comprehensive assessment of prokaryotic communities in th...
Article
With thousands of discovered planets orbiting other stars and new missions that will explore our solar system, the search for life in the universe has entered a new era. However, a reference database to enable our search for life on the surface of icy exoplanets and exomoons by using records from Earth's icy biota is missing. Therefore, we develope...
Article
Full-text available
Methylmercury (MeHg) is a toxic and bioaccumulative organo-metallic compound that is naturally produced in many ecosystems. Organisms that occupy the lower trophic positions in food webs may be key factors in the assessment of MeHg biomagnification between ecosystems. Here we present a review of the peer-reviewed literature examining MeHg bioac-cum...
Article
Full-text available
The Great Whale River in subarctic Quebec, Canada, is one of the main freshwater inflows to Hudson Bay. This region is experiencing rapid climate change, with pronounced impacts on the cryosphere, and ongoing socio-economic development that may accelerate with future road and shipping links. This review integrates information available to date on t...
Conference Paper
Full-text available
Warming of the circumpolar north is accelerating permafrost thaw, with implications for landscapes, hydrology, ecosystems and the global carbon cycle. In subarctic Canada, abrupt permafrost thaw is creating widespread thermokarst lakes. Little attention has been given to small waterbodies with area less than 10,000 m 2 , yet these are biogeochemica...
Article
Deception Island is an active volcano in the Antarctica being volcanism a source of mercury. To improve the understanding of the Hg cycle in this remote ecosystem, pyroclastic gravel and water samples were collected and total (THg) and monomethylmercury (MMHg) concentrations were measured as well as the potential for Hg methylation. Gravel samples...
Preprint
Full-text available
In situ air concentrations of gaseous elemental mercury (Hg(0)) and vegetation–atmosphere fluxes were quantified in both high (Cala Norte, CN) and low-to-moderate (Alcochete, ALC) Hg-contaminated saltmarsh areas of the Tagus estuary colonized by plant species Halimione portulacoides (Hp) and Sarcocornia fruticosa (Sf). Atmospheric Hg(0) ranged betw...
Article
Full-text available
Thermokarst lakes result from the thawing of ice-rich permafrost and are widespread across northern landscapes. These waters are strong emitters of methane, especially in permafrost peatland regions, where they are stained black by high concentrations of dissolved organic matter (DOM). In the present study, we aimed to structurally characterize the...
Article
Full-text available
Bacterial natural products (NPs) are still a major source of new drug leads. Polyketides (PKs) and non-ribosomal peptides (NRP) are two pharmaceutically important families of NPs and recent studies have revealed Antarctica to harbor endemic polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes, likely to be involved in the pro...
Article
Full-text available
Thermokarst waterbodies caused by permafrost thawing and degradation are ubiquitous in many subarctic and Arctic regions. They are globally important components of the biogeochemical carbon cycle and have potential feedback effects on climate. These northern waters are mostly small lakes and ponds, and although they may be mapped using very high-re...
Article
The plant Halimione portulacoides, an abundant species widely distributed in temperate salt-marshes, has been previously assessed as bioindicator and biomonitor of mercury contamination in these ecosystems. The present study aims to assess uptake and distribution of total mercury (THg) and methylmercury (MMHg) within H. portulacoides, potential mer...
Article
Background: Neuronal and sensory toxicity of mercury (Hg) compounds has been largely investigated in humans/mammals with a focus on public health, while research in fish is less prolific and dispersed by different species. Well-established premises for mammals have been governing fish research, but some contradictory findings suggest that knowledg...
Article
Salt marshes act as natural deposits of different metals (e.g. heavy-metals), while halophyte plants are known to retain and accumulate them in the different tissues. Scarce data exists on accumulation, partition and fractionation of YREE in these plants. To study the relationship between halophyte plants and YREE, contents of these metals were det...
Poster
Some of the icy moons of Jupiter and Saturn (e.g. Europa, Ganymede and Enceladus) are thought to be habitable environments that may host extra-terrestrial life . Ecosystems analogue to environments on Earth may exist in these icy world . Preparatory work using Earth samples that are analogous to icy moons is critical for the success of future space...
Article
Full-text available
Microbial activity is a critical factor controlling methylmercury formation in aquatic environments. Microbial communities were isolated from sediments of two highly mercury-polluted areas of the Tagus Estuary (Barreiro and Cala do Norte) and differentiated according to their dependence on oxygen into three groups: aerobic, anaerobic, and sulphate-...
Article
Mercury naturally contaminated environments, like Deception Island (Antarctica), are field labs to study the physiological consequences of chronic Hg-exposure at the community level. Deception Island volcanic vents lead to a continuous chronic exposure of the phytoplanktonic communities to potentially toxic Hg concentrations. Comparing Hg-contamina...
Article
This study examined the susceptibility of fish (Liza aurata) eyes and brain to metals(loids) contamination under realistic exposure conditions. A multidimensional approach was applied to fish caught at a chronically contaminated site (BAR) and at a reference site of the Tagus estuary (Portugal), which comprised metals(loids) accumulation in eyes an...
Conference Paper
Full-text available
The yttrium and rare earth elements (YREE) increased use has resulted in a large widespread in the aquatic environment, and particularly, in estuaries, where salt marshes act as natural deposits of different contaminants from industrial and urban wastes (Brito et al., 2018). Halophyte plants, such as Sarcocornia fruticosa and Spartina maritima, kno...
Article
Full-text available
Mercury (Hg) distribution in saltmarsh sediments and in three selected halophytes (Limonium narbonense, Sarcocornia fruticosa and Atriplex portulacoides) of a wetland system (Marano and Grado Lagoon, Italy) following a contamination gradient in sediments was investigated. The Hg uptake was evaluated at the root system level by calculating the enric...
Article
Six campaigns were performed in North Channel (CNOR), Barcas Channel (BC) and lower zones (EZ) of Tagus estuary to better understand methylmercury (MMHg) and mercury (Hg) transport and fate. Highest concentrations of particulate and dissolved MMHg were observed in CNOR in bottom waters and in the warmest months. The MMHg distribution coefficients b...
Article
Mercury (Hg) reduction performed by microorganisms is well recognized as a biological means for remediation of contaminated environment. Recently, studies demonstrated that Hg-resistant microorganisms of Tagus Estuary are involved in metal reduction processes. In the present study, aerobic microbial community isolated from a highly Hg-contaminated...
Article
Full-text available
Mercury (Hg) dynamics was evaluated in contaminated sediments and overlying waters from Tagus estuary, in two sites with different Hg anthropogenic sources: Cala Norte (CNOR) and Barreiro (BRR). Environmental factors affecting methylmercury (MMHg) production and Hg and MMHg fluxes across sediment/water interface were reported. [THg] and [MMHg] in s...
Article
Intertidal sediments of Tagus estuary regularly experiences complex redistribution due to tidal forcing, which affects the cycling of mercury (Hg) between sediments and the water column. This study quantifies total mercury (Hg) and methylmercury (MMHg) concentrations and fluxes in a flooded mudflat as well as the effects on water-level fluctuations...
Article
This study examines, for the first time, the neurotoxicity of Hg(II) and MeHg in fish (Diplodus sargus) in a time-course comparative perspective and considering realistic exposure levels and routes. Both forms followed an identical time-variation pattern of accumulation in the brain, but dietary MeHg was more efficiently transported to the brain. M...
Article
Neurotoxic methylmercury (MMHg) is formed from inorganic divalent mercury (Hg 2þ). However, it is poorly understood to what extent different mercury (Hg) pools contribute to existent MMHg levels. In this study, ambient concentrations of total Hg (THg) and MMHg as well as rates of methylation and demethylation were measured simultaneously in sedimen...
Article
Full-text available
The Tagus Estuary is one of the most Hg-contaminated estuaries in SW Europe. Sediment cores were sampled at two low Hg-contaminated sites inside the natural park, Alcochete (ALC) and Vale Frades (VF), and analyzed for mercury and methylmercury. Concentrations of Hg and MeHg in sediments were below 1 μg g⁻¹ and 4.4 ng g⁻¹, respectively. While in sum...
Article
The current study aims to shed light on the neurotoxicity of MeHg in fish (white seabream − Diplodus sargus) by the combined assessment of: (i) MeHg toxicokinetics in the brain, (ii) brain morphometry (volume and number of neurons plus glial cells in specific brain regions) and (iii) fish swimming behavior (endpoints associated with the motor perfo...
Article
Oceans constitute one of the most important reservoirs for mercury. In order to provide a first insight into the concentrations of Hg species in the Atlantic sector of the Southern Ocean a sampling campaign was carried out south of the Polar Front.
Article
Full-text available
The Ardley Cove area (located on the Maxwell Bay shoreline, Fildes Peninsula, King George Island, Antarctica) is characterized not only by its high biodiversity, but also by a high density of scientific stations, making it potentially one of the most impacted areas of Antarctica. In order to assess the source, contamination levels, distribution and...
Article
Full-text available
The Arctic is a water-rich region, with freshwater systems covering about 16 % of the northern permafrost landscape. Permafrost thaw creates new freshwater ecosystems, while at the same time modifying the existing lakes, streams, and rivers that are impacted by thaw. Here, we describe the current state of knowledge regarding how permafrost thaw aff...
Conference Paper
Full-text available
Neurotoxic methylmercury (MeHg) is formed from inorganic divalent mercury (HgII). However, it is poorly understood to what extent different geochemical Hg pools contribute to existent MeHg levels. Many procedures have been developed to measure the concentration of MeHg from different sample matrices, and the use of isotope enriched mercury species...
Article
Full-text available
There are several aspects of inorganic mercury (iHg) toxicokinetics in fish that remain undeveloped despite its environmental ubiquity, bioaccumulation capacity and toxicity. Thus, this study presents the uptake, distribution and accumulation of iHg following water contamination by adopting a novel set of body compartments (gills, eye wall, lens, b...
Article
Full-text available
Deception Island is an active volcano located in the Antarctic Peninsula, a region with a very complex geotectonic setting. The associated Quaternary volcanism is directly linked to the recent rifting in the Bransfield back-arc basin which, in turn, is associated to the subduction of Phoenix plate under the Antarctic plate that became inactive 4 Ma...
Conference Paper
Full-text available
Estuaries are highly dynamic links between the terrestrial and ocean reservoirs. Resolution of the biogeochemical cycle of mercury (Hg) within estuaries is complicated by their physical, chemical and hydrological dissimilarities, variation in productivity, biodiversity, differences in Hg inputs and propensity for Hg bioaccumulation in food webs. On...
Conference Paper
The Polar Research Group of the University of Lisbon has been studying the ice-free areas of the Antarctic Peninsula region for several years and conducting both field data collection with multiple techniques and also remote sensing imagery analysis. The recent technological developments of Unmanned Aerial Vehicles, allowing for fully automatical a...
Article
Full-text available
Mercury (Hg) contamination of aquatic systems has been recognized as a global, serious problem affecting both wildlife and humans. High levels of Hg, in particular methylmercury (MeHg), were detected in surface sediments of Tagus Estuary. MeHg is neurotoxic and its concentration in aquatic systems is dependent upon the relative efficiency of reduct...
Conference Paper
Full-text available
Mercury is one of the major contaminants due to its toxicity and easy bioaccumulates in aquatic systems. The Tagus estuary has been contaminated by mercury from an inoperative industrial plant in Barreiro and an operative chloralkali industry in Cala Norte. To better understand Hg distribution in intertidal sediments, sampling campaigns were done c...
Conference Paper
Biogeochemistry of methylmercury (MeHg) in sediments is not completely understood, regarding seasonal and spatial variations within estuaries. Historical mercury (Hg) contamination in Tagus estuary is known but MeHg variability is poorly documented. Here, seasonality of MeHg is assessed in pore waters for the first time and in solid sediments from...
Poster
Full-text available
The multivariate statistical technique of Principal Component Analysis (PCA) was applied in this work to study interrelationships of sediment parameters and metal speciation data (Hg and MeHg), as well as spatial variations in different sites from Tagus estuary (CN, BRR, ALC and VF). Data pre-treatment and descriptive statistics allowed the interpr...
Conference Paper
n order to understand carbon and nutrients biogeochemical cycling in Tagus estuary intertidal sediments, cores were collected in contrasting mudflats: Barreiro (BRR), subjected to high anthropogenic pressure, Alcochete (ALC) under moderate/small pressure and Vale de Frades (VF) in Tagus natural reserve. Analyses of pore waters organic dissolved car...
Article
Full-text available
Mercury occurrence was evaluated in samples of edible muscle tissue of 27 blue sharks (Prionace glauca) caught in the Atlantic Ocean, adjacent to the south and southeastern Brazilian coast, indicating a slight increase in comparison with previous data obtained for the same studied area and being higher than those fish caught at different sites of t...