What are the key factors influencing sediment quality along Western European rivers?
The composition of sediments in rivers and large streams provides indicators on many processes in the critical zone such as chemical pollution. Since 1945, a large amount of data was produced in Europe by managers and researchers to assess and monitor the quality of water bodies. Within the framework of the Interpol project, a database of 12,000 samples was implemented to study the key factors involved in the variability of metal concentrations in sediments between 1945 and 2020 along 7 European river corridors (Rhone, Seine, Lot-Garonne, Loire, Scheldt, Meuse and Rhine). The exploitation of these data allowed us to determine that spatial (location) and temporal (critical pollution period) factors were the most significant. At this scale, factors such as the analytical protocol or the type of matrix have a secondary influence on the variability of concentrations. Trend analysis of Cd, Pb and Zn showed that the middle and downstream sections of the corridors are affected by urban and industrial hotspots, while upstream contamination is mostly influenced by historical mining areas. This work has made all the data compiled available to the scientific community and managers and provides new results concerning the effectiveness of regulations.
(04/07/2022)
LEHNA, UCBL, ENTPE, CNRS, LEHNA IAPHY, LEHNA, UCBL, ENTPE, CNRS, GEDI, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, OFB - DRAS, OFB, GéHCO, UT
Approche optique et moléculaire non-ciblée pour caractériser et tracer les sources naturelles et anthropiques de matière organique dissoute (MOD) à l'échelle d'un bassin versant péri-urbain Auteurs
Les activités anthropiques à l’échelle d’un bassin-versant peuvent être très nombreuses (e.g. pratiques agricoles, industrielles, transport, tourisme). Ces activités engendrent des pressions qui se manifestent par l’apport de polluants vers les cours d’eau (e.g. micropolluants organiques, métaux traces). Il reste encore difficile d’identifier l’ensemble de ces sources de polluants au niveau d’un bassin versant péri-urbain. Du fait de son ubiquité, la matière organique dans sa fraction dissoute (MOD) constitue un complexe de molécules originaire à la fois ces activités mais également de sources plus naturelles (e.g. lixiviation de sols non-anthropisé, production autochtone). Ainsi, cette étude vise à déterminer si la MOD à travers ses propriétés optiques et moléculaires peut constituer un marqueur de sources naturelles et anthropiques. Pour cela, différentes sources typiques d’occupations de sols forestières, agricoles, mais également issues de rejets de stations de traitement des eaux usées et de ruissellements urbains ont été identifiées et prélevées à l’échelle d’un bassin-versant périurbain (Bassin de l’Yzeron, Observatoire de terrain en hydrologie urbaine). La MOD des échantillons a été caractérisée par une série de techniques analytiques optiques (UV-Vis, fluorescence 3D et HPSEC/UV-fluo) et moléculaire (LC-HRMS). Des analyses statistiques ont étaient appliquées sur le jeu de données généré pour identifier des marqueurs de sources échantillonnées a priori. Les résultats montrent qu’une combinaison pertinente d’indicateurs optiques permet de différencier les types de sources naturelles et anthropiques de MOD. Les données issues des analyses moléculaires ont permis de mettre en évidence un ensemble de molécules communes à toutes les sources de MOD mais surtout des ensembles de molécules typique de chaque type de source. Ces empreintes moléculaires typiques sont caractérisées par des classes de polarité et de masse de molécules.
(04/07/2022)
RiverLy, INRAE, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Copper contamination in vineyard soils of Bordeaux: spatial risk assessment for the replanting of vines and crops
Copper (Cu) is widely and historically used in viticulture as a fungicide against mildew. Cu has a strong affinity for soil organic matter and accumulates in topsoil horizons. Thus, Cu may negatively affect soil organisms and plants, consequently reducing soil fertility and productivity. The Bordeaux vineyards have the largest vineyard surfaces (26%) within French controlled appellation and a great proportion of French wine production (around 5 million hl per year). Considering the local context of vineyard surfaces decreasing (vine uprooting) and possible new crop plantation, the issue of Cu potential toxicity rises. Therefore, the aims of this work are firstly to evaluate the Cu contamination in vineyard soils of Bordeaux, secondly to produce a risk assessment map for new vine or crop plantation. We used soil analyses from several local studies to build a database with 4496 soil horizon samples. The database was enhanced by means of pedotransfer functions in order to estimate the bioaccessible (EDTA-extractable) Cu in soils of samples without measurements. From this database, 1797 georeferenced samples with CuEDTA concentrations in the topsoil (0-50 cm depth) were used for kriging interpolation in order to produce the spatial distribution map of CuEDTA in vineyard soils. Then, the spatial distribution of Cu was crossed with vine uprooting surfaces and municipality boundaries. CuEDTAconcentrations ranged from 0.52 to 459 mg/kg and showed clear anomalies. Our results from spatial analysis showed that almost 50% of vineyard soil surfaces have CuEDTA concentrations higher than 30 mg/kg (moderate risk for new plantation) and 20% with concentrations higher than 50 mg/kg (high risk for new plantation). A decision-support map based on municipalities was realised to provide a simple tool to stakeholders concerned by land use management.
(03/07/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Bordeaux Sciences Agro
Giant deep submarine depressions: A combined dissolution-mechanical process along carbonate margins
Abstract Submarine depressions are common features on the eastern Bahamian seafloor but the genesis of the deepest ones (>4000 m in water depth) is not well understood. We conducted a morphometric analysis and compared them to a worldwide database of rounded depressions, whatever their genesis is. The deep Bahamian depressions are large elongated structures, among the largest on Earth, with a width greater than 1000 m and a depth sometimes greater than 200 m. They extend at the toe of the Blake Bahama Escarpment (BBE), one of the tallest escarpments on Earth. Some of them align parallel to the BBE. Other depressions align along large submarine canyon axes. When aligned along canyon axes, the depressions closest to the canyon head are flanked by a topographic high interpreted as a slope-break deposit, i.e., sediment deposited after flow expansion following a hydraulic jump. Turbidity currents in the carbonate canyon system are not permanent processes, but are rather triggered during sea-level highstands when the carbonate platform is flooded. In addition, some depressions are not located in canyon axes. Consequently, the size and location of the depressions are not likely explained by a simple plunge pool mechanical erosion. Rather, our data suggest that all depressions could be initiated by giant karstic dissolution structures (dolines or sinkholes). Under interpretation, those located in canyon axes are sporadically refreshed by carbonate-laden turbidity currents. The height of the outsized chutes marking the crossing of the BBE by the canyon mouth generates a hydraulic jump allowing sediment deposition toward the bottom of the depression. Large depressions observed at this location in the Bahamas were the result of an initial dissolution phase related to retreat of the BBE and the more recent sediment-laden flow activity. The depressions orientated along canyon axes facilitated the regressive erosion that formed the canyons. At present, the depressions located at canyon mouths act as regular plunge pools.
(Geological Society of America Bulletin. vol. 135, n° 0016-7606, pp. 743-752, 02/07/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Metal contamination and heat stress impair swimming behavior and acetylcholinesterase activity in embryo-larval stages of the Mediterranean mussel, Mytilus galloprovincialis
Behavioral parameters are increasingly considered sensitive and early bioindicators of toxicity in aquatic organisms. A video-tracking tool was specifically developed to monitor the swimming behaviour of D-larvae of the Mediterranean mussel, Mytilus galloprovincialis, in controlled laboratory conditions. Both maximum and average swimming speeds and trajectories were recorded. We then investigated the impact of copper and silver with or without a moderate rise of temperature on swimming behavior and acetylcholinesterase (AChE) activity of mussel D-larvae and the possible mechanistic link between both biological responses. Our results showed that copper and/or silver exposure, as well as temperature increase, disrupts the swimming behavior of mussel larvae which could compromise their dispersal and survival. In addition, the combined effect of temperature and metals significantly (p < 0.05) increased AChE activity in mussel larvae. Pearson's correlation analysis was performed and results showed that the AChE activity is positively correlated with maximum speeds (r = 0.71, p < 0.01). This study demonstrates the value of behavioral analyzes of aquatic invertebrates as a sensitive and integrate marker of the effects of stressors.
(Marine Environmental Research. vol. 179, n° 0141-1136, 01/07/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Correction: Gasperi et al. Micropollutants in Urban Runoff from Traffic Areas: Target and Non-Target Screening on Four Contrasted Sites. Water 2022, 14, 394
In the original publication [...]
(Water. vol. 14, n° 2073-4441, pp. 2215, 01/07/2022)
GERS-LEE, LEESU, ENPC, UPEC UP12, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEDI, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LUT, Cerema, ENPC
Role of iron in gene expression and in the modulation of copper uptake in a freshwater alga: Insights on Cu and Fe assimilation pathways.
Metal uptake and toxicity can generally be related to its aqueous speciation and to the presence of competitive ions as described by the biotic ligand model. Beyond these simple chemical interactions at the surface of aquatic organisms, several internal biological feedback mechanisms can also modulate metal uptake. This is particularly important for essential elements for which specific transport systems were developed over the course of evolution. Based on the results of short-term Cu2+ uptake experiments and on the analysis of the expression of certain genes involved in Cu and Fe homeostasis, we studied the effects of Fe3+ on Cu2+ uptake by the freshwater green alga Chlamydomonas reinhardtii. We observed a significant increase in Cu2+ uptake rate in algal cells acclimated to a low Fe3+ medium up to 4.7 times greater compared to non-acclimated algal cells. The overexpression of the ferroxidase FOX1 and permease FTR1 genes suggests an activation of the high affinity Fe3+ assimilation system, which could constitute a plausible explanation for the increase in Cu2+ uptake rate in acclimatized algae. We show that Fe availability can have a significant impact on Cu uptake. Our observations reinforce the importance of considering physiological factors to better predict metal bioavailability.
(Environmental Pollution. vol. 305, n° 0269-7491, pp. 119311, 01/07/2022)
BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact of terrestrial biosphere on the atmospheric CO<sub>2</sub> concentration across Termination V
Among the 100 kyr climatic cycles of the Late Pleistocene, Termination V (TV, ∼ 433-404 kyr BP), the fifth last deglaciation, stands out for its minimum in astronomical forcing associated paradoxically with maxima in sea level, Antarctic temperature and atmospheric CO 2 concentration. However, the driving mechanisms explaining TV remain only partially understood. For instance, climate models cannot fully represent the atmospheric CO 2 variation observed in paleoclimate data. Aside from essential oceanic circulation processes, there is increasing evidence that terrestrial biosphere may have played a key role in the global carbon cycle. This study proposes a three-step integrated approach, combining regional and global vegetation records with modelling results, to unveil the evolution of terrestrial biosphere and its contribution to the carbon cycle during TV. First, we provide a new high-resolution (∼ 700 years) deep-sea pollen record from the Gulf of Cádiz (site U1386, 36 • 49.680 N; 7 • 45.320 W) for TV, which shows a moderate expansion of the Mediterranean forest. We then construct the first global forest pollen database for this period. Our compilation features distinct evolutions for different types of forest, highlighting a strong development of temperate and boreal forest which might have delayed the atmospheric CO 2 increase during TV. Finally, the direct comparison of global simulated forests (iLOVECLIM model) to our pollen database reveals overall consistent temperate and boreal forest evolutions despite model biases, thereby supporting the hypothesis of a significant CO 2 sequestration by middle and high-latitude forests of the Northern Hemisphere shortly after the onset of TV.
(Climate of the Past. vol. 18, n° 1814-9324, pp. 1429 - 1451, 27/06/2022)
ENS-PSL, PSL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPHE, PSL, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CLIM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Characterization of the metabolomic response of freshwater biofilms to urban wastewater effluents
Urban wastewater treatment plants (WWTPs) release large amounts of pollutants (e.g. chemicals, microbes) into aquatic environments that may impact exposed organisms. Among these organisms, aquatic biofilms, as a complex assemblage of microorganisms with a short life cycle (e.g. microalgae, bacteria) and by their key role in aquatic ecosystems (e.g. primary production), are relevant and increasingly used to investigate the impact of chemical contamination at the community level. Despite increasing knowledge on the impact of chemical stress on these communities, the underlying (molecular/biochemical) mechanisms remain poorly described while usual descriptors provide a partial picture of the phenotype. To tackle this issue, untargeted metabolomics approach is relevant through the simultaneous characterization of chemical exposure and the global response of the whole biofilm. In this context, this study focuses on the characterization of the potential impact of urban WWTPs on aquatic periphytic microbial communities by implementing an untargeted metabolomic approach. To do so, biofilm colonization/exposure was carried out during 4 weeks at upstream and downstream sites from three WWTPs along the main tributary of Arcachon Bay (Belin Béliet: upstream, Salles: intermediate; Mios: downstream). First, multivariate analyses (PCA and HCA) showed discrepancies in the metabolomics profile between the three WWTPs and between upstream and downstream site of each WWTP. This difference is more marked at the downstream site (Mios), likely because of increasing disturbances along the tributary (e.g detection of pesticides only on the downstream site). Moreover, the strong discrimination between upstream and downstream sites at Mios suggested that this WWTP is a source of pollutants. At this site, further univariate analysis combined to pathways analysis allowed preliminary annotation (i.e. based only on MS1) that highlighted a potential impact on the respiration and photosynthesis pathways. Overall, this study confirms the relevance of untargeted metabolomics to highlight potential impact of urban discharges on aquatic microbial communities.
(20/06/2022)
UR EABX, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, CNRS, INRAE
Redescription of Apocorophium acutum (Crustacea, Amphipoda, Corophiidae) with material from type locality and key of world Apocorophium species
Apocorophium acutum (Chevreux, 1908), the type species of the genus, was originally but only partially described by Chevreux with female specimens from Bônes (Algeria); male specimens were later described from Brittany (France). Since then, the species has been recorded in different places of the world, some of them questionable. Herein, the species is entirely redescribed with material from the type locality and Brittany, and additional material from Arcachon Bay is studied to provide biological data. The known geographical distribution of this species is summarized, and a world identification key of Apocorophium species is also given.
(Zookeys. vol. 1106, n° 1313-2989, pp. 101-119, 17/06/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS