The long-term evolution of pico- and nanophytoplanktonic communities in two coastal contrasting sites from the bay of Toulon was studied using monthly flow cytometry analyses during a seven-year ...period. Results highlighted higher abundance of both pico- and nanophytoplanktonic communities in the more eutrophic site (i. e. the Little Bay). Moreover, even if both sites were widely dominated by Synechococcus spp. population, it represented more than 90% of the population during summer in the Large Bay. Using diversity indices and rank frequency diagrams to study ecological successions in both sites, communities from the Little Bay (the most polluted site) appeared, paradoxically, as more diversified and more mature than that from the Large Bay. Communities from the Large Bay appeared as less diversified and juvenile linked to the dominance of Synechococcus spp. The complementarity of diversity indices and rank frequency diagram was revealed in this present work.
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•Combined use of diversity indices and RFD is relevant to study coastal ecosystems.•Ecosystems were more diversified and mature in the more polluted site.•Synechococcus spp. population widely dominated coastal areas from the Bay of Toulon.
Toulon bay is severely impacted by metal contamination induced by past and recent naval activities. In this work, Cu, Zn and Pb isotope compositions and elemental concentrations of fifty-five surface ...sediments were determined in order to map the spatial distribution of anthropogenic and natural sources along this land-sea continuum. Two sub-systems of Toulon Bay, the Small and Large bays, showed well-marked patterns on metal contamination levels and isotope signatures for Cu and Pb. The Small bay had the highest metal concentrations, and displayed average Pb and Cu isotope compositions of 1.1664 ± 0.0043 (1s, expressed as 206Pb/207Pb ratios) and −0.17 ± 0.19‰ (1s, expressed as δ65CuNIST values), respectively. It contrasted with the Large bay, with moderate to pristine metal concentrations and average Pb and Cu isotope compositions of 1.1763 ± 0.0079 (1s) and +0.08 ± 0.23‰ (1s), respectively. Lead isotope systematics indicated a binary source mixing process involving industrial and natural sources, while Cu isotope systematics showed a ternary mixing process involving two distinct anthropogenic signatures, interpreted as associated to new diffuse anthropogenic sources and old warfare material. In contrast, Zn isotope compositions in the Small and Large bays were practically the same: +0.06 ± 0.05‰ and +0.06 ± 0.11‰ (1s, expressed δ66ZnJMC values), respectively, denoting an overlap between isotope signatures of natural and anthropogenic sources. This study presents the first detailed spatial distributions of Cu and Zn isotope compositions for an aquatic system, and demonstrates the feasibility to use Cu isotopes as tracers of anthropogenic sources in coastal environments.
•Cu isotope systematic show a mixing process of natural and anthropogenic sources.•Low Cu contaminated sediments display δ65CuNIST values ranging from 0.0 to +0.2‰.•Contaminated sediments by diffuse sources tend to negative δ65CuNIST values.•Pb isotopes reveal mixing process involving industrial and natural sources.•Zn isotope system does not allow identifying mixing source processes.
This paper presents the investigation of strontium isotope ratios of about 650 different European natural mineral waters as part of the food traceability project “TRACE” funded by the EU. Analysed
...87Sr/
86Sr values in the natural mineral waters range from 0.7035 to 0.7777, which indicates an influence by a great diversity of rocks from young mantle derived basaltic rocks to very old silicic continental crust.
The results of the large scale investigation are used to elaborate a novel spatial prediction for strontium isotope ratios by combining the measured data with a GIS based geological map of Europe.
The resulting map can be used to predict the strontium isotopic composition of groundwater and thus the composition of bio-available strontium, which is available for uptake by plants and subsequently transferred into the food chain. We also show, as an example, that the strontium isotopic composition of honey and wheat from specific sample regions within the TRACE project correlates well with that of the natural mineral water as predicted by our map.
The proof of principle shown in our paper is highly relevant for geographical food authentication as it allows an assessment of the origin of food products without the immediate need for geographically authenticated materials which may not always be available. Our approach provides a cost effective first instance screening tool.
Mercury (Hg) is a global contaminant of environmental concern. Numerous factors influencing its bioaccumulation in marine organisms have already been described at both individual and species levels ...(e.g., size or age, habitat, trophic level). However, few studies have compared the trophic characteristics of ecosystems to explain underlying mechanisms of differences in Hg bioaccumulation and biomagnification among food webs and systems. The present study aimed at investigating the potential primary role of the trophic status of systems on Hg bioaccumulation and biomagnification in temperate marine food webs, as shown by their medium-to high-trophic level consumers. It used data from samples collected at the shelf-edge (i.e. offshore organisms) in two contrasted ecosystems: the Bay of Biscay in the North-East Atlantic Ocean and the Gulf of Lion in the North-West Mediterranean Sea. Seven species including crustaceans, sharks and teleost fish, previously analysed for their total mercury (T-Hg) concentrations and their stable carbon and nitrogen isotope compositions, were considered for a meta-analysis. In addition, methylated mercury forms (or methyl-mercury, Me-Hg) were analysed. Mediterranean organisms presented systematically lower sizes than Atlantic ones, and lower δ13C and δ15N values, the latter values especially highlighting the more oligotrophic character of Mediterranean waters. Mediterranean individuals also showed significantly higher T-Hg and Me-Hg concentrations. Conversely, Me-Hg/T-Hg ratios were higher than 85% for all species, and quite similar between systems. Finally, the biomagnification power of Hg was different between systems when considering T-Hg, but not when considering Me-Hg, and was not different between the Hg forms within a given system. Overall, the different parameters showed the crucial role of the low primary productivity and its effects rippling through the compared ecosystems in the higher Hg bioaccumulation seen in organisms from oligotrophic Mediterranean waters.
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•Seven offshore species from the Mediterranean Sea and the Atlantic Ocean examined.•Individual sizes, δ13C and δ15N values, Hg concentrations and speciation compared.•Mediterranean and Atlantic organisms differed for most of the parameters studied.•δ15N values reflected the different trophic status at the base of the two systems.•Oligotrophy likely drives the higher Hg bioaccumulation by Mediterranean organisms.
Higher Hg bioaccumulation by Mediterranean organisms likely linked to the lower primary productivity (oligotrophy) of Mediterranean waters in comparison with Atlantic waters.
In this work, a multi-elemental approach combining Cu and Zn stable isotopes is used to assess the metal contamination evolution in the Loire estuary bulk sediments. Elemental geochemical data ...indicate an increase of metal concentrations from the beginning of the industrial period peaking in the 1990s, followed by an attenuation of metal contamination inputs to the estuary. Zinc isotope compositions suggest a binary mixing process between Zn derived from terrigenous material and multi-urban anthropogenic sources. Copper isotope systematics indicate a single natural dominant source represented by weathered silicate particles from soils and rocks. This work demonstrates the applicability of Zn isotopes to identify anthropogenic Zn sources in coastal systems, even under a low to moderate degree of contamination. Further studies are required to constrain Cu sources and to elucidate possible effects of grain-size and mineralogy in the Cu isotope composition of sediment in the Loire estuary.
•Geochemical data and Cu and Zn isotopes were investigated in the Loire estuary.•Cu and Zn isotope compositions of sediments vary in spatial and temporal scales.•Zinc isotopes suggest a mixing process between terrigenous and urban sources.•Cu isotopes indicate a natural dominant source represented by weathered material.
The development of 3D printing in recent years opens up a vast array of possibilities in the field of flow analysis. In the present study, a new 3D-printed flow system has been developed for the ...selective spectrophotometric determination of lead in natural waters. This system was composed of three 3D-printed units (sample treatment, mixing coil and detection) that might have been assembled without any tubing to form a complete flow system. Lead was determined in a two-step procedure. A preconcentration of lead was first carried out on TrisKem Pb Resin located in a 3D-printed column reservoir closed by a tapped screw. This resin showed a high extraction selectivity for lead over many tested potential interfering metals. In a second step, lead was eluted by ammonium oxalate in presence of 4-(2-pyridylazo)-resorcinol (PAR), and spectrophotometrically detected at 520nm. The optimized flow system has exhibited a linear response from 3 to 120µgL−1. Detection limit, coefficient of variation and sampling rate were evaluated at 2.7µgL−1, 5.4% (n=6) and 4 sampleh−1, respectively. This flow system stands out by its fully 3D design, portability and simplicity for low cost analysis of lead in natural waters.
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•A 3D-printed Multi Pumping Flow System is presented.•Selective extraction of lead using Triskem Pb resin enables elimination of interferences.•Pb2+ can be quantified between 3 and 120µgL−1 with a LOD of 2.7µgL−1.•This flow system is a low cost and portable system allowing in-situ measurement.
Platinum (Pt) is considered a Technology Critical Element (TCE) and an emerging metallic contaminant with increasing release into the environment. Gaps in knowledge and understanding of environmental ...levels, fate and effects of Pt still exist, especially in the marine environment. This work presents Pt concentrations in the northwestern Mediterranean coast including: (i) temporal variability from sediment cores and farmed mussels in the Toulon Bay (historically affected by intense human activities) and (ii) spatial distribution from recent wild mussels collected along ∼ 700 km coastline with contrasting ecosystems (including natural reserves), quantified using voltammetry and inductively coupled plasma-mass spectrometry. The historical (>100 years) record of Pt in sediments from the Toulon Bay suggests the existence of non-negligible Pt sources older than those related to vehicle emission devices, such as petrol industry and coal-fired activities. A strong Pt increase in more recent sediments (from ∼12 to 16 ng g−1) and mussels (8-fold increase from ∼0.12 to 0.80 ng g−1) covering the past 25 years reflect the overall evolution of Pt demand in Europe (∼20-fold increase for vehicle catalysts in 20 years). Spatial biomonitoring of Pt in mussels along the northwestern Mediterranean coast is assumed to reflect inter-site differences of Pt exposure (0.09–0.66 ng g−1) despite seasonal effect on tissue development. This study highlights the need for thorough and regular monitoring of Pt levels in sediments and biota from urbanized coastal areas in order to better assess the environmental impact of this TCE, including potential risks for marine organisms.
•Platinum levels were monitored in contrasting sites of the NW Mediterranean coast.•Historical sediments reflect non-vehicle related, old Pt anthropogenic sources.•Past 25-years sediments and mussels show recent vehicle related Pt contamination.•Biomonitoring mussels reflect the degree of Pt contamination in coastal environment.
Primary consumers play a key role in coastal ecosystems by transferring organic matter from primary producers to predators. Among them, suspension-feeders, like bivalve molluscs are widely used in ...trophic web studies. The main goal of this study was to investigate variations of C and N elemental and isotopic ratios in common bivalves (M. edulis, M. galloprovincialis, and C. gigas) at large spatial (i.e. among three coastal regions) and different temporal (i.e. from seasonal to multi-decadal) scales in France, in order to identify potential general or specific patterns and speculate on their drivers.
The observed spatial variability was related to the trophic status of the coastal regions (oligotrophic Mediterranean Sea versus meso- to eutrophic English Channel and Atlantic ocean), but not to ecosystem typology (estuaries, versus lagoons versus bays versus littoral systems). Furthermore, it highlighted local specificities in terms of the origin of the POM assimilated by bivalves (e.g., mainly continental POM vs. marine phytoplankton vs. microphytobenthic algae). Likewise, seasonal variability was related both to the reproduction cycle for C/N ratios of Mytilus spp. and to changes in trophic resources for δ13C of species located close to river mouth. Multi-decadal evolution exhibited shifts and trends for part of the 30-year series with decreases in δ13C and δ15N. Specifically, shifts appeared in the early 2000's, likely linking bivalve isotopic ratios to a cascade of processes affected by local drivers.
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•Trophic status of coastal ecosystems explains the geographical variation of bivalve δ13C and δ15N.•Seasonal variability in C/N is related to reproduction cycle for mussel species.•δ13C seasonal variability is related to trophic resource variability for C. gigas and M. edulis.•Multi-decadal shifts and trends in C/N ratio, δ13C and δ15N were detected and likely related to climate change.
Here, we evaluate for the first time the performances of the newly developed laser direct infrared (LDIR) technique and propose an optimization of the initial protocol for marine microplastics (MPs) ...analysis. Our results show that an 8 μm porosity polycarbonate filter placed on a Kevley slide enables preconcentration and efficient quantification of MPs, as well as polymer and size determination of reference plastic pellets of polypropylene (PP), polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET), with recoveries ranging from 80–100% and negligible blank values for particle sizes ranging from 200 to 500 μm. A spiked experiment using seawater, sediment, mussels, and fish stomach samples showed that the method responded linearly with significant slopes (R 2 ranging from 0.93–1.0; p < 0.001, p < 0.01). Overall, 11 polymer types were identified with limited handling and an analysis time of ca. 3 h for most samples and 6 h for complex samples. Application of this technique to Mediterranean marine samples (seawater, sediment, fish stomachs and mussels) indicated MP concentrations and size distribution consistent with the literature. A high predominance of PVC (sediment, fish stomachs) and PE and PP (seawater, mussels) was observed in the analyzed samples.
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