Emmanuel Tessier

Hydrô Réunion · Management

Estos lagos son nichos ecológicos únicos para especies endémicas y migratorias, y su estudio es crucial para entender la biogeoquímica en ambientes extremos. En este sentido, los lagos del Altiplano, como: las lagunas Colorada, Verde y Blanca, tienen niveles extremos de arsénico (80 mg L−1 en el agua y 6.5 g kg−1 en sedimentos), como también concen...

The gold extraction process by mercury amalgamation is recognized worldwide as a process presenting an environmental and health risk linked to mercury contamination of the geo and biosphere close to the gold panning site. The aim of this work is to assess the risk of contamination by mercury of populations living in the locality of Bétaré-oya, whic...

Molybdate inhibits sulfate respiration in sulfate-reducing bacteria (SRB). It is used as an inhibitor to indirectly evaluate the role of SRB in mercury methylation in the environment. Here, the SRB Pseudodesulfovibrio hydrargyri BerOc1 was used to assess the effect of molybdate on cell growth and mercury methylation under various metabolic conditio...

Accurate interpretation of mercury (Hg) isotopic data requires the consideration of several biotic factors such as age, diet, geographical range, and tissue metabolic turnover. A priori knowledge of prey-predator isotopic incorporation rates and Hg biomagnification is essential. This study aims to assess Hg stable isotopes incorporation in an Arcti...

Identifying metabolism and detoxification mechanisms of Hg in biota has important implications for biomonitoring, ecotoxicology, and food safety. Compared to marine mammals and waterbirds, detoxification of MeHg in fish is understudied. Here, we investigated Hg detoxification in Atlantic bluefin tuna Thunnus thynnus using organ- specific Hg and Se...

Methylmercury in soils and vegetation from the Amazonian rainforest is still poorly studied. Hence, the aim of this work was to determine the total mercury [THg] and methylmercury [MeHg] concentrations in litter and surface soil, MeHg deposition via litterfall, and the MeHg fate during a forest fire in the Amazonian rainforest. Sampling of litter,...

Identifying Hg sources to aquatic ecosystems and processes controlling the levels of monomethylmercury (MMHg) is critical for developing efficient policies of Hg emissions reduction. Here we measured Hg concentrations and stable isotopes in sediment, seston and fishes from the various basins of the Baltic Sea, a large brackish ecosystem presenting...

Mercury (Hg) emissions from forest fires, especially tropical forests such as the Amazonian forest, were shown to contribute significantly to the atmospheric mercury budget, but new methods are still necessary to improve the traceability and to reduce the great uncertainties related to this emission source. Recent studies have shown that the combus...

Mercury (Hg) has been recognized as a global pollutant owing to its volatility from anthropogenic sources and long-range transport. Microbial-mediated transformations of Hg species are key processes for understanding the environmental impact of Hg. Until know, effort has been made by using pure cultures, while insight into Hg pathways at the commun...

The key factors which affect the abiotic photodemethylation process of monomethylmercury (MMHg) in the freshwaters has remained unclear. Hence, this work aimed to better elucidate the abiotic photodemethylation pathway in a model freshwater. Anoxic and oxic conditions were implemented to investigate the simultaneous photodemethylation to Hg(II) and...

This work quantified the accumulation efficiencies of Hg in cuttlefish, depending on both organic (MeHg) and inorganic (Hg(II)) forms, under increased pCO2 (1600 μatm). Cuttlefish were fed with live shrimps injected with two Hg stable isotopic tracers (Me202Hg and 199Hg(II)), which allowed for the simultaneous quantification of internal Hg accumula...

The sulphur cycle has a key role on the fate of nutrients through its several interconnected reactions. Although sulphur cycling in aquatic ecosystems has been thoroughly studied since the early 70's, its characterisation in saline endorheic lakes still deserves further exploration. Gallocanta Lake (NE Spain) is an ephemeral saline inland lake whos...

This study investigates the seasonality of the mercury (Hg) concentration of olive tree foliage, an iconic tree of the Mediterranean basin. Hg concentrations of foliage, stems, soil surface, and litter were analyzed on a monthly basis in ancient olive trees growing in two groves in Lebanon, Bchaaleh and Kawkaba (1300 and 672 m a.s.l. respectively)....

Mercury (Hg) is a highly toxic metal that adversely impacts human and wildlife health. The amount of Hg released globally in the environment has increased steadily since the Industrial Revolution, resulting in growing contamination in biota. Seabirds have been extensively studied to monitor Hg contamination in the world's oceans. Multidecadal incre...

Total and dissolved concentrations of inorganic mercury (IHg) and methylmercury (MeHg) in water (Adour Estuary) were determined during three sampling campaigns and related to biogeochemical variables (nutrients, organic matter). Factors (sampling time, sample type) were included in analysis of covariance with effect separation. The urban estuary su...

While mercury (Hg) is a major concern in all aquatic environments because of its methylation and biomagnification pathways, very few studies consider Hg cycling in remote alpine lakes which are sensitive ecosystems. Nineteen high-altitude pristine lakes from Western/Central Pyrenees were investigated on both northern (France) and southern (Spain) s...

Mercury (Hg) is a global pollutant of environmental and health concern; its methylated form, methylmercury (MeHg), is a potent neurotoxin. Sulfur-containing molecules play a role in MeHg production by microorganisms. While sulfides are considered to limit Hg methylation, sulfate and cysteine were shown to favor this process. However, these two form...

Seafood has a great ecological and nutritional value for human and wildlife communities. However, accumulation of mercury (Hg) in fish is a concern to animal and human health. There is a crucial need to understand Hg speciation in marine organisms through controlled feeding experiments. This study represents a first assessment of the biological pro...

The speciation of both redox reactive and volatile selenium (Se) compounds, barely reported in pristine aquatic environments, has never been investigated in remote alpine lakes, considered as sensitive ecosystems to detect the effect of global change. This work presents an integrated investigation on Se distribution and speciation conducted in 20 h...

Mercury (Hg) is a global pollutant of environmental and health concern; its methylated form, methylmercury (MeHg) is a potent neurotoxin. Sulfur-containing molecules play a role in MeHg production by microorganisms. While sulfides are considered to limit Hg methylation, sulfate and cysteine were shown to favor this process. However, these two forms...

Mercury (Hg) pollution in the ocean is an issue of global concern, however bioaccumulation regimes of this ubiquitous pollutant in marine apex predators have important knowledge gaps. Our fish length and stable isotope (δ15N and δ13C) normalized data of Greenland halibut (GH) (Reinhardtius hippoglossoides) showed that Hg bioaccumulation in fillet t...

The present study aims to explore the bioaccumulation and biotic transformations of inorganic (iHg) and monomethyl mercury (MMHg) by natural pico-nanoplankton community from eutrophic lake Soppen, Switzerland. Pico-nanoplankton encompass mainly bacterioplankton, mycoplankton and phytoplankton groups with size between 0.2 and 20 μm. Species-specific...

The Hg isotopic composition of 1-year-old Norway spruce (Picea abies) shoots collected from Saarland cornurbation Warndt, Germany, since 1985 by the German Environmental Specimen Bank, were measured for a better understanding of the temporal trends of Hg sources. The isotopic data showed that Hg was mainly taken up as gaseous element mercury (GEM)...

Hg accumulation in marine organisms depends strongly on in situ water or sediment biogeochemistry and levels of Hg pollution. To predict the rates of Hg exposure in human communities, it is important to understand Hg assimilation and processing within commercially harvested marine fish, like the European seabass Dicentrarchus labrax. Previously, va...

In shallow aquatic environments, sediment is a significant source of monomethylmercury (MMHg) for surface water (SW). High-altitude aquatic ecosystems are characterized by extreme hydro-climatic constraints (e.g., low oxygen and high UV radiation). We studied, during two seasons, the diel cycles of MMHg in SW and sediment porewaters (PW) of Lake Ur...

The four largest freshwater lakes in southwestern France are of both ecological and economic importance. However, some of them are subjected to mercury (Hg) contamination, resulting in the ban of human consumption of piscivorous fish. Moreover, beyond predatory fish, little information exist regarding Hg levels in other species of these ecosystems....

Microorganisms are key players in the transformation of mercury into neurotoxic methylmercury (MeHg). Nevertheless, this mechanism and the opposite MeHg demethylation remain poorly understood. Here, we explored the impact of inorganic mercury (IHg) and MeHg concentrations from 0.05 to 50 μM on the production and degradation of MeHg in two sulfate-r...

A citer sous la forme : Wickel J., Fricke R., Durville P., Chabanet P., Dumestre M., Mulochau T., Pinault M., Tessier E. (2020). Updated checklist of the fish species of Reunion Island, 1-25, in: Dumestre & Wickel (2020). Évaluation de statuts de conservation pour les poisons récifaux à la Réunion. Marex/Deal 974, 27 pp+ annexes.

An interlaboratory study on the National Institute for Environmental Studies (NIES) certified reference material (CRM) No. 28 Urban Aerosols, collected on the filters of a central ventilating system in a building in Beijing city center, was performed to obtain informative values of Hg isotopic composition and total Hg (THg) mass fraction. The THg m...

Mercury (Hg) pollution threatens ecosystems and human health. Wastewater treatment plants (WWTPs) play a key role in limiting Hg discharges from wastewaters to rivers and lakes, but large-scale studies to estimate Hg loads and discharge at national levels are scarce. We assessed the concentration, flux, speciation, and removal of Hg in 64 (pre-stud...

Mercury (Hg) and lead (Pb) isotopic compositions were investigated in mosses and lichenscollected in a large mountainous beech forest (Iraty Forest) located on the French-SpanishPyrenean border. Hg isotopic signature in topsoil samples were also analyzed in selectedsampling sites. This is thefirst work that uses the complementary information of bot...

Microbial mercury (Hg) methylation transforms the inorganic mercury (Hg(II)) to the neurotoxin methylmercury (MeHg) in anoxic marine sediments. Both geochemical parameters and microbial activities constrain the net MeHg production, and were studied in the Capbreton Canyon. Twenty-three deep sea surface sediments were investigated within the first 3...

Submarine canyons are important stocks of commercial interest fish, whose consumption is one of the main monomethymercury (MeHg) exposure to humans. Currently, biogeochemistry of mercury in those biologically productive system is unknown. In this work, inorganic mercury (Hg(II)) and organic mercury (MeHg) distributions were measured in sedimentary...

In coastal environments, oscillating redox conditions represent a functional state affecting organic matter mineralization. Such transient diagenetic processes remain difficult to study in situ, and we therefore designed a specific reactor to provide experimental results that are environmentally relevant in this context. Here, we present the result...

Mercury (Hg) and methyl mercury (MeHg) concentrations have never been measured in sediments of coastal lakes of Aquitaine, although high concentrations of Hg have been measured in fish. Our objective was to characterize benthic biogeochemical processes and the distribution of Hg in lake sediments and to connect these results with fish contamination...

Hardangerfjord is one of the longest fjords in the world and has historical mercury (Hg) contamination from a zinc plant in its inner sector. In order to investigate the extent of Hg transferred to abiotic and biotic ecosystem compartments, Hg and monomethylmercury (MeHg) concentrations were measured in seawater, sediment, and seafood commonly cons...

In the South Indian Ocean, French territories include Reunion (Mascarene archipelago), Mayotte (Comoros archipelago) and the remote Iles Eparses in the Mozambique Channel (Glorieuses, Juan de Nova, Bassas da India, Europa), and Tromelin, North-East of Madagascar. Their coral reefs are varied, from 18 km2 of fringing reefs in Reunion to 1500 km2 of...

The sources and factors controlling concentrations of monomethylmercury (MMHg) in aquatic ecosystems need to be better understood. Here, we investigated Hg transformations in sediments, periphyton associated to green algae or aquatic plants and benthic biofilms from the Lake Titicaca hydrosystem and confronted them to the occurrence of active methy...

Priority substances set by the Water Framework Directive (WFD) are of major interest to evaluate the quality of coastal and marine systems, the final receptors for pollutant emissions. Emerging substances not regulated by the WFD, i.e. personal care products and pharmaceuticals, are of high concern since only scarce information of their occurrence,...

In this study, axenic cultures of sulfate-reducing (SRB) and nitrate-reducing (NRB) bacteria were examined for their ability to methylate inorganic tin and to methylate or dealkylate butyltin compounds. Environmentally relevant concentrations of natural abundance tributyltin (TBT) and 116Sn-enriched inorganic tin were added to bacterial cultures to...

Caractérisation de la forêt de mangrove de Madagascar pour actualiser l'estimation des stocks de production de crabe Scylla serrata.

Lake Uru Uru (3686 m a.s.l.) located in the Bolivian Altiplano region receives both mining effluents and urban wastewater discharges originating from the surrounding local cities which are under rapid development. We followed the spatiotemporal distribution of different mercury (Hg) compounds and other metal(oid)s (e.g., Fe, Mn, Sb, Ti and W) in bo...

The "strategic analysis" has been conducted in 2012-2014 as part of the process of creation of the Coral Sea nature park, an MPA located in New Caledonia. This document aims at giving a synthesis of the available knowledge and identifying key conservation and socio-economic issues that will be adressed by the Park's management plan in the future. A...

The first chapter of this booklet presents a synthesis of the management issues identified through the strategic analysis of the maritime space of New Caledonia, as a basis for the creation of the "Coral Sea Nature Park" in New Caledonia, one of the biggest MPA in the world in 2014. The second part of the book presents the boundaries, the manageme...

The reef fauna connectivity of the West Indian Ocean (WIO) is one of the least studied globally. Here we use genetic analyses of the grouper Epinephelus merra (Bloch 1793) to determine patterns of connectivity and to identify barriers to dispersal in this WIO marine area. Phylogeographic and population-level analyses were conducted on cytochrome b...

A b s t r a c t An annotated checklist of the fish species of La Réunion (southwestern Indian Ocean) comprises a total of 984 species in 164 families (including 16 species which are not native). 65 species (plus 16 introduced) occur in fresh-water, with the Gobiidae as the largest freshwater fish family. 165 species (plus 16 introduced) live in tra...

Examining the genetic structure of species allows an estimate of the level of evolutionary connectivity between localities; this information is important for marine biodiversity protection, in particular, for the delineation of marine protected areas. In this context, a total of 601 Lutjanus kasmira (Forsskål, 1775) were sampled in 16 localities of...

The reef fish Myripristis berndti (Jordan & Everman 1903) is a pantropical species. A genetic analysis was conducted on 353 individuals from 10 localities distributed across the SW Indian Ocean (SWIO) in order to determine patterns of connectivity in the SWIO. Both the mtDNA sequences (711-bp cytochrome b sequences) and the microsatellites (8 newly...

The objectives of marine protected areas (MPA), such as Reunion’s Marine Reserve founded in 2007, are (i) protect habitats (ecosystems) and resources (biodiversity) from increasing pressure due to a major urban, economic and recreational development; ii) manage uses and conflicts between traditional fisheries, spear-fishing, diving and recreational...

Scheme for classification of species to functional feeding groups. (0.05 MB DOC)

Fit of linear, polynomial, exponential, and power models to the relationship between standing biomass as the dependent variable and functional richness as the independent variable. (0.06 MB DOC)

Data used to establish the link between energy consumption and body mass in fishes. (0.25 MB DOC)

Effect of the number of individuals on the relationship between diversity and standing biomass. (0.14 MB DOC)

Standing biomass as a surrogate of ecosystem processes. (1.25 MB DOC)

Interpretation of the significant interaction between human density and biodiversity. (0.07 MB DOC)