Application of a multidisciplinary and integrative weight-of-evidence approach to a 1-year monitoring survey of the Seine River
Quality assessment of environments under high anthropogenic pressures such as the Seine Basin, subjected to complex and chronic inputs, can only be based on combined chemical and biological analyses. The present study integrates and summarizes a multidisciplinary dataset acquired throughout a 1-year monitoring survey conducted at three workshop sites along the Seine River (PIREN-Seine program), upstream and downstream of the Paris conurbation, during four seasonal campaigns using a weight-of-evidence approach. Sediment and water column chemical analyses, bioaccumulation levels and biomarker responses in caged gammarids, and laboratory (eco)toxicity bioassays were integrated into four lines of evidence (LOEs). Results from each LOE clearly reflected an anthropogenic gradient, with contamination levels and biological effects increasing from upstream to downstream of Paris, in good agreement with the variations in the structure and composition of bacterial communities from the water column. Based on annual average data, the global hazard was summarized as “moderate” at the upstream station and as “major” at the two downstream ones. Seasonal variability was also highlighted; the winter campaign was least impacted. The model was notably improved using previously established reference and threshold values from national-scale studies. It undoubtedly represents a powerful practical tool to facilitate the decision-making processes of environment managers within the framework of an environmental risk assessment strategy.
(Environmental Science and Pollution Research. vol. 25, n° 0944-1344, pp. 23404-23429, 01/08/2018)
SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, UR HBAN, IRSTEA, ULB, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEDI, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA, IRSTEA, ESE, UP11, CNRS
A nonlinear weakly dispersive method for recovering the elevation of irrotational surface waves from pressure measurements
We present the derivation of a nonlinear weakly dispersive formula to reconstruct , from pressure measurements, the surface elevation of nonlinear waves propagating in shallow water. The formula is simple and easy to use as it is local in time and only involves first and second order time derivatives of the measured pressure. This novel approach is evaluated on laboratory and field data of shoaling waves near the breaking point. Unlike linear methods, the nonlinear formula is able to reproduce at the individual wave scale the peaked and skewed shape of nonlinear waves close to the breaking point. Improvements in the frequency domain are also observed as the new method is able to accurately predict surface wave elevation spectra over four harmonics. The nonlinear weakly dispersive formula derived in this paper represents an economic and easy to use alternative to direct wave elevation measurement methods (e.g. acoustic surface tracking and LiDAR scanning)..
(Coastal Engineering. vol. 138, n° 0378-3839, pp. 1 - 8, 01/08/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMB, UB, Bordeaux INP, CNRS, LIENSs, INSU - CNRS, ULR, CNRS, LEGI, Grenoble INP, CNRS, UGA [2016-2019], CNRS, UGA [2016-2019], Grenoble INP ENSGI, Grenoble INP, UGA [2016-2019]
A two-million-year-long hydroclimatic context for hominin evolution in southeastern Africa
The past two million years of eastern African climate variability is currently poorly constrained, despite interest in understanding its assumed role in early human evolution. Rare palaeoclimate records from northeastern Africa suggest progressively drier conditions or a stable hydroclimate. By contrast, records from Lake Malawi in tropical southeastern Africa reveal a trend of a progressively wetter climate over the past 1.3 million years. The climatic forcings that controlled these past hydrological changes are also a matter of debate. Some studies suggest a dominant local insolation forcing on hydrological changes whereas others infer a potential influence of sea surface temperature changes in the Indian Ocean. Here we show that the hydroclimate in southeastern Africa (20–25° S) is controlled by interplay between low-latitude insolation forcing (precession and eccentricity) and changes in ice volume at high latitudes. Our results are based on a multiple-proxy reconstruction of hydrological changes in the Limpopo River catchment, combined with a reconstruction of sea surface temperature in the southwestern Indian Ocean for the past 2.14 million years. We find a long-term aridification in the Limpopo catchment between around 1 and 0.6 million years ago, opposite to the hydroclimatic evolution suggested by records from Lake Malawi. Our results, together with evidence of wetting at Lake Malawi, imply that the rainbelt contracted toward the Equator in response to increased ice volume at high latitudes. By reducing the extent of woodland or wetlands in terrestrial ecosystems, the observed changes in the hydroclimate of southeastern Africa—both in terms of its long-term state and marked precessional variability—could have had a role in the evolution of early hominins, particularly in the extinction of Paranthropus robustus.
(Nature. vol. 560, n° 0028-0836, pp. 76 - 79, 01/08/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GFZ, MARUM, PACEA, UB, CNRS, UNIVERSITé DE DURHAM, JAMSTEC, CLIM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, VUB, GM, IFREMER
A simple and accurate nonlinear method for recovering the surface wave elevation from pressure measurements
(30/07/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMB, UB, Bordeaux INP, CNRS, LIENSs, INSU - CNRS, ULR, CNRS, LEGI, Grenoble INP, CNRS, UGA [2016-2019]
Monsoonal Forcing of European Ice‐Sheet Dynamics During the Late Quaternary
(Geophysical Research Letters. vol. 45, n° 0094-8276, pp. 7066-7074, 24/07/2018)
IMCCE, INSU - CNRS, CNRS, PSL, SU, CNRS, GM, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, NOC
Kromdraai, a Plio-Pleistocene cave deposit in the Cradle of Humankind World Heritage Site, South Africa
(09/07/2018)
WITS, UT3, Comue de Toulouse, Inrap, UP, TRACES, EHESS, UT2J, Comue de Toulouse, MCC, Inrap, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE
Mise en œuvre d’un outil intégratif permettant la quantification et la spatialisation des apports azotés influençant un captage d’alimentation en eau potable –Approche à l’échelle de l’hydrosystème karstique des Sources du Toulon (Périgueux, France)
(pp. 118-119, 02/07/2018)
I2M-BX, UB, CNRS, INRAE, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SNO Karst, INSU - CNRS, SU
VSI: Environmental concentrations, cycling and modeling of technology critical elements
Tailings containing mining and ore treatment waste, accumulated over long time periods are major contaminant sources at the watershed scale and may seriously impair environmental quality of river-sea continuums. A critical review of existing work in different disciplines addressing the multi-metal contamination of the Gironde Watershed, a major fluvial-estuarine model system representative of many other systems worldwide, has provided a condensed, yet pertinent overview on various aspects of this environmental problem. Combining long-term observation and contamination records from different environmental archives, there is a clear trend towards resilience for the main historical contaminants (Cd, Zn, Pb and Cu), yet suggesting that resilience needs appropriate management of both, tailings as the initial source and contaminated sediments acting as temporary metal traps which may transform into delayed sources. Contaminated sediment management is an increasingly important challenge due to (i) successful remediation at the contamination source itself (ii) global-change induced factors and strategies and (iii) lacking coordination of actions between upstream and downstream parts of the fluvial-estuarine continuum. Less studied and emerging metallic contaminants show recent trends in sediments and biota that are decoupled from the legacy contaminant trajectories due to recent sources and applications, suggesting that further work is needed to assess their potential impact on the environmental quality of the Gironde fluvial-estuarine system and that of other systems, especially in a context of worldwide rapidly growing mining activity and metal use.
(Science of the Total Environment. vol. 630, n° 0048-9697, pp. 32, 01/07/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Spatio-temporal variation of trematode parasites community in Cerastoderma edule cockles from Ria de Aveiro (Portugal)
Cerastoderma edule (edible cockle) is among the most exploited bivalves in Europe playing an important socio-economic role. Cockles live in estuaries and lagoons where their population is controlled by several environmental factors including parasitism. Parasites represent an important part of the world known biodiversity but are often neglected. Trematodes are the most prevalent macroparasites of cockles being able to exert an impact both at the individual and population levels. Therefore, it is of prime relevance to recognize and understand the parasite-host system dynamics in order to better predict potential conservation threats to bivalve populations and to maximize the success of stock and disease episodes management. Cockle monitoring was conducted in 2012 and 2016, in six and eight stations, respectively, at the Ria de Aveiro coastal lagoon, Portugal. Cockles were sampled in one single occasion in 2012 and seasonally in 2016. The tested hypothesis is that the trematode community in cockles was spatially and seasonally heterogeneous but stable over time. The main result showed that despite a relative homogeneity of the parasite community structure in cockles, the among-years heterogeneity of trematode communities was higher than among-stations and among-seasons heterogeneity rejecting the postulated hypothesis. Results demonstrated that trematode communities from the Ria de Aveiro are characterized by low abundance, which resulted in a spatial and seasonal trematode homogeneity (despite an overall channel difference and a slight downstream-upstream gradient). The interannual analysis showed a worrisome loss of trematode diversity and prevalence which consequently indicates an important loss of overall diversity and/or environmental conditions reflecting the negative effects of global change (mean temperature rise and overharvesting, among others). The present study highlighted the importance of trematodes in characterising their associated environment and respective biodiversity which might be helpful to assess ecosystem ecological status and to identify threatened areas.
(Environmental Research. vol. 164, n° 0013-9351, pp. 114-123, 01/07/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Palaeoclimate constraints on the impact of 2 °C anthropogenic warming and beyond
Over the past 3.5 million years, there have been several intervals when climate conditions were warmer than during the pre-industrial Holocene. Although past intervals of warming were forced differently than future anthropogenic change, such periods can provide insights into potential future climate impacts and ecosystem feedbacks, especially over centennial-to-millennial timescales that are often not covered by climate model simulations. Our observation-based synthesis of the understanding of past intervals with temperatures within the range of projected future warming suggests that there is a low risk of runaway greenhouse gas feedbacks for global warming of no more than 2 °C. However, substantial regional environmental impacts can occur. A global average warming of 1–2 °C with strong polar amplification has, in the past, been accompanied by significant shifts in climate zones and the spatial distribution of land and ocean ecosystems. Sustained warming at this level has also led to substantial reductions of the Greenland and Antarctic ice sheets, with sea-level increases of at least several metres on millennial timescales. Comparison of palaeo observations with climate model results suggests that, due to the lack of certain feedback processes, model-based climate projections may underestimate long-term warming in response to future radiative forcing by as much as a factor of two, and thus may also underestimate centennial-to-millennial-scale sea-level rise.
(Nature Geoscience. vol. 11, n° 1752-0894, pp. 474 - 485, 01/07/2018)
CEP, UNIBE, OCCR, UNIBE, CCRC, UNSW, CEOAS, OSU, ANU, CAM, MPI-M, BAS, NERC, NBI, UCPH, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LDEO, MARUM, UNIVERSITé DE DURHAM, AWI, CAM, UNIGE, UNIL, GEOTOP, EPM, UdeM, UQAT, UQAR, UQAM, USC, UAM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GLACCIOS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, NCAR, PSL, CAU, UFZ, UNIBE, NZC, IAP, CAS