Commercial traceability of <i>Arapaima</i> spp. fisheries in the Amazon basin: can biogeochemical tags be useful?

The development of analytical tools to determine the origin of fishes is useful to better understand patterns of habitat use and to monitor, manage, and control fisheries, including certification of food origin. The application of isotopic analyses to study calcified structures of fishes (scales, vertebrae, and otoliths) may provide robust information about the fish geographic origin and environmental living conditions. In this study, we used Sr and C isotopic markers recorded in otoliths of wild and farmed commercialized pirarucu (Arapaima spp.) to evaluate their prediction potential to trace the fishes origin. Wild and farmed fish specimens, as well as food used for feeding pirarucu in captivity, were collected from different sites. Isotope composition of otoliths performed by isotope-ratio mass spectrometry (IRMS; δ13C) and femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (LAfs-MC-ICPMS; 87Sr∕86Sr) were compared to the isotopic composition of water and of the food given to the fishes in the farms. Wild fish specimens that lived in environments with the largest fluctuation of river water Sr isotope ratios over time presented the largest Sr isotope variations in otoliths. A quadratic discriminant analysis on otolith isotopic composition provided 58&thinsp;% of correct classification for fish production (wild and farmed) and 76&thinsp;% of correct classification for the fish region. Classification accuracy for region varied between 100&thinsp;% and 29&thinsp;% for the Madeira and the Lower Amazon fishes, respectively. Overall, this preliminary trial is not yet fully developed to be applied as a commercial traceability tool. However, given the importance of Arapaima spp. for food security and the generation of economic resources for millions of people in the Amazon basin, further analyses are needed to increase the discrimination performance of these biogeographical tags.</p

Commercial traceability of <i>Arapaima</i> spp. fisheries in the Amazon basin: can biogeochemical tags be useful?

The development of analytical tools to determine the origin of fishes is useful to better understand patterns of habitat use and to monitor, manage, and control fisheries, including certification of food origin. The application of isotopic analyses to study calcified structures of fishes (scales, vertebrae, and otoliths) may provide robust information about the fish geographic origin and environmental living conditions. In this study, we used Sr and C isotopic markers recorded in otoliths of wild and farmed commercialized pirarucu (Arapaima spp.) to evaluate their prediction potential to trace the fishes origin. Wild and farmed fish specimens, as well as food used for feeding pirarucu in captivity, were collected from different sites. Isotope composition of otoliths performed by isotope-ratio mass spectrometry (IRMS; δ13C) and femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (LAfs-MC-ICPMS; 87Sr∕86Sr) were compared to the isotopic composition of water and of the food given to the fishes in the farms. Wild fish specimens that lived in environments with the largest fluctuation of river water Sr isotope ratios over time presented the largest Sr isotope variations in otoliths. A quadratic discriminant analysis on otolith isotopic composition provided 58&thinsp;% of correct classification for fish production (wild and farmed) and 76&thinsp;% of correct classification for the fish region. Classification accuracy for region varied between 100&thinsp;% and 29&thinsp;% for the Madeira and the Lower Amazon fishes, respectively. Overall, this preliminary trial is not yet fully developed to be applied as a commercial traceability tool. However, given the importance of Arapaima spp. for food security and the generation of economic resources for millions of people in the Amazon basin, further analyses are needed to increase the discrimination performance of these biogeographical tags.</p

Mercury Isotopic Fractionation during Pedogenesis in a Tropical Forest Soil Catena (French Guiana): Deciphering the Impact of Historical Gold Mining

ISI Document Delivery No.: GX5UI Times Cited: 0 Cited Reference Count: 65 Guedron, S. Arnouroux, D. Tessier, E. Grirnaldi, C. Barre, J. Berail, S. Perrot, V Grimaldi, M. Guedron, Stephane/0000-0003-4229-1566 Agence National pour la Recherche (ANR) through the project Interconnect [ANR-CESA 020 06] This study was funded by the Agence National pour la Recherche (ANR) through the project Interconnect (ANR-CESA 020 06 coordinated by Noureddine Bousserrhine from UPEC in Creteil). The authors gratefully acknowledge Cayian Feng from IPREM in Pau, Max Sarrazin and Patrick Seyler from the IRD center in Cayenne, Nicolas Gilliet from INRA in Rennes, and Tchia and Bruno Levessier from Qimbe Kio for their help in the laboratory and with field work and logistics. The authors thank the CMB company (Compagnie Miniere Boulanger) for providing us the access to the mine as well as the high-resolution topographic map used in Figure 1'. The authors also gratefully acknowledge Daniel Sabatier for his help in the identification and characterization of palm trees and leaves. The authors finally gratefullly thank the anonymous reviewers (especially reviewer 3) for their constructive reviews that allowed us to greatly improve the manuscript. 0 11 Amer chemical soc Washington 1520-5851International audienceWe used natural mercury (Hg) stable isotopes to investigate the Hg cycle in a rainforest soil catena (French Guiana) partially gold-mined during the early 1950s. Litterfall showed homogeneous Δ199Hg values [-0.18 ± 0.05‰, i.e., a modern gaseous elemental Hg (GEM) isotopic signature]. After litter decomposition, Hg bound to organic matter (OM) is mixed with Hg from pristine (-0.55 ± 0.22‰) or gold-mined (-0.09 ± 0.16‰) mineral materials. Negative Δ199Hg values in deep pristine mineral horizons (-0.60 ± 0.16‰) suggest the transfer of Hg bound to dissolved OM depleted in odd isotopes due to mass-independent fractionation during Hg abiotic reduction. Perennial palm tree leaves collected above gold-mined and pristine soil recorded contrasting Δ199Hg signatures likely resulting from GEM re-emission processes from soils and leaf surfaces. Upslope, soil δ202Hg signatures showed a negative shift (ϵ ∼ -1‰) with depth attributed to mass-dependent fractionation during Hg sorption and complexation onto iron oxides and dissolved OM. Downslope, higher δ202Hg values in soils resulted from hydromorphy [lower humification, greater Hg(II) reduction, etc.]. The unique Hg isotopic signatures of Amazonian soils probably result in multistep fractionation processes during pedogenesis (millions of years) and in a potentially different Hg isotopic signature of preanthropogenic background GEM

Belgium

Intrinsic biogeochemical markers, such as stable isotope ratios of carbon (C), nitrogen (N), sulphur (S) and mercury (Hg) are increasingly used to trace the effects of trophic ecology on Hg accumulation in marine top predators. However, they are often used separately. This leaves the interpretation of the data at times incomplete. Using a multivariate approach could contend with the complexity of the natural world and reveal patterns that would not be detectable by univariate methods. Our main objective was to assess which factor influences the most Hg sourcing in Arctic marine top predators and evaluate the consequences relative to the rates of exposure. We measured THg levels, C, N, S and Hg stable isotopes in three true seal species living in the Greenland Sea: the hooded seal Cystophora cristata, the harp seal Pagophilus groenlandicus and the ringed seal Pusa hispida. They present distinct habitat use, diet and geographical distribution. We integrated all the measured parameters into a multivariate analysis and quantify species multi-isotopic niches (SEAs) with SIBER. The multi-isotopic niches of the three species resulted highly separated. Hooded seals presented the largest multivariate SEA (Mode, 95% CI: 0.93, 0.60 – 1.41), a result of its highly distributed oceanic behaviour. Harp seals presented the second largest SEA (Mode, 95% CI: 0.31, 0.14 – 0.68), while ringed seals presented the smallest niche (Mode, 95% CI: 0.22, 0.14 – 0.37) as a result of its strong territoriality within the Scoresby Sound. Ringed seals presented the highest THg levels (1190±488 ng.g-1 dw), followed by hooded (881±942 ng.g-1 dw) and harp seals (407±289 ng.g-1 dw). Our study showed how habitat use (offshore / bentho-pelagic for Cc vs. offshore / pelagic for Pg vs. coastal / sympagic for Ph) is the most important factor influencing Hg accumulation in Arctic true seals. A species like the ringed seal; which lives in the fjords, on land-fast ice, is more influenced by the enhanced MeHg production typical of these zones and accumulate higher levels of Hg compared to offshore hooded and harp seals.SODYAR

Dispersal capacities of anadromous Allis shad population inferred from a coupled genetic and otolith approach

cited By 4International audienceUnderstanding dispersal capacities for migratory species is crucial for their management. By coupling otolith microchemistry and microsatellite genetic analyses, we provided information on snapshot and long-term dispersal capacity of Allis shad (Alosa alosa), an anadromous clupeid in decline throughout its distribution range. The allocation of natal origin was obtained from water chemistry and signatures in otoliths of juveniles and spawners within a Bayesian model. The majority of adults were assigned to a source river with high degrees of confidence; only 4% were undetermined. Otolith natal origins were used to define a population baseline by grouping individuals from the same natal river and not from the same sampling location as usually done. While A. alosa exhibited a high level of natal site fidelity, this species showed weak genetic structure, which supported the evidence of a substantial flow of strayers between river basins in the vicinity or at longer distances. However, long distance straying was probable but not frequent. In a context of global change, straying would be a key mechanism to drive dispersal and allow resilience of Allis shad populations

Evaluating the role of local mercury sources on spatial and temporal pollution trends in marine predators living in a changing arctic

peer reviewedThe consequences of a rapidly warming Arctic on environmental mercury (Hg) exposure in marine biota remains largely unknown. Stable carbon (C), nitrogen (N), sulphur (S) and Hg isotope ratios are increasingly used to harmonice and trace Hg sources, pathways and concentrations in marine top predators. Our objective was to identify Hg sources in marine Arctic predators at spatial and temporal scale and evaluate the consequences on Hg exposure over time. We measured THg concentrations, C, N, S, and Hg isotope ratios in muscle tissue of hooded Cystophora cristata and ringed seal Pusa hispida from East Greenland, collected between 1985 and 2019. We created multi-isotopic niches (standard ellipse areas, SEAs), after which we applied linear mixed models to relate temporal variation in Hg exposure and sources to environmental change (e.g. sea-ice, NAO). Hooded seals presented a larger SEA (mode, 95% CI: 0.93, 0.60 – 1.41) than ringed seals (mode, 95% CI: 0.22, 0.14 – 0.37). Ringed seals showed higher THg concentrations (Mean ± SD: 1.10 ± 0.48 µg g-1 dw) than hooded seals (0.88 ± 0.92 µg g-1 dw) on average. THg levels in hooded seal muscle decreased by 1.5% y-1, while no significant change was found for ringed seals. At spatial scale, habitat use (oceanic vs. coastal) was the most important driver of THg variability, with landfast ice-associated ringed seals being potentially influenced by enhanced coastal MeHg emission and accumulate higher THg levels. Attemporal scale, the shift in local marine biogeochemistry (represented by δ15N values) and prey biomass were the most important drivers of THg in ringed and hooded seals, respectively. The different Hg trends shown by the two species suggested how Hg sources are important drivers of bioaccumulation in Arctic seals, underling the necessity to reevalute their importance for the forecasting of future Hg trends in the Arctic Ocean

Is it really organic? - multi-isotopic analysis as a tool to discriminate between organic and conventional plants

Novel procedures for analytical authentication of organic plant products are urgently needed. Here we present the first study encompassing stable isotopes of hydrogen, carbon, nitrogen, oxygen, magnesium and sulphur as well as compound-specific nitrogen and oxygen isotope analysis of nitrate for discrimination of organically and conventionally grown plants. The study was based on wheat, barley, faba bean and potato produced in rigorously controlled long-term field trials comprising 144 experimental plots. Nitrogen isotope analysis revealed the use of animal manure, but was unable to discriminate between plants that were fertilized with synthetic nitrogen fertilizers or green manures from atmospheric nitrogen fixing legumes. This limitation was bypassed using oxygen isotope analysis of nitrate in potato tubers, while hydrogen isotope analysis allowed complete discrimination of organic and conventional wheat and barley grains. It is concluded, that multi-isotopic analysis has the potential to disclose fraudulent substitutions of organic with conventionally cultivated plants