Impacts of Mayan land use on Laguna Tusp an watershed (Pet en, Guatemala) as seen through clay and ostracode analysis
Most of the cities built by the Mayas in the Pet en area, in the Central Yucat an Peninsula, were abandoned 1200 to 1000 years ago. The phenomenon is sometimes un-appropriately called " the collapse of the Maya civilization ". Its main causes are still debated, ranging from climatic according to the occurrence of severe or modest droughts, to societal in the form of environmental mismanagement of the environment. In both processes, it is inferred that stress triggered the formation in many Pet en lake sediments of erosional clay deposits, known as 'Maya clays'. This work presents a high resolution, multi-proxy study of 'Maya clays' in lacustrine sediments from Laguna Tusp an, near the archaeological site of La Joyanca. Micropaleontological (ostracodes), mineral-ogical (clay minerals) and geochemical (bulk elemental composition and stable isotopes in organic carbon) records reveal three different phases of soil erosion throughout the last 5300 years. The oldest phase from 5281 to 2998 cal yr BP (i.e. 3331 e 1048 BC) is characterized by successive natural and moderate soil erosion deposits which follow climatic variations recorded in the American tropical belt. The time interval between 2998 and 1281 cal yr BP (i.e. 1048 BC and AD 661) contains four distinct erosional layers which, according to clay mineralogy, are indicative of both increased erosion of the regolith and strong soil loss. The most recent, also the most massive, deposit of Maya clay ends around 1281 cal yr BP (AD 661), that is some 200 years before the so-called 'Maya collapse' in the Pet en area. Recent archeological fieldwork studies indicate that a population mobility took place into the city of La Joyanca from its hinterland by the early Late Classic Period (ca. AD 600), that is, at the end or just after this erosion episode, and well before the occurrence of the Terminal Classic-Postclassic (AD 800e1250) drastic climatic changes. Shifts in environmental management by the local society and timing of urbanization may explain environmental changes better than droughts per se.
(Journal of Archaelogical Science. vol. 49, pp. 372-382, 23/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEODE, UT2J, Comue de Toulouse, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France]
Preface "The changing Arctic and Subarctic environment: proxy- and model-based reconstructions of Holocene climate variability in the northern North Atlantic
This special issue originates from the EU FP7-Marie Curie initiative "CASE" (The Changing Arctic and Subarctic Environment), an Initial Training Network (ITN) on marine biotic indicators of recent climate changes in the high latitudes of the North Atlantic (http://caseitn.epoc.u-bordeaux1.fr/). This four-year project (April 2010-March 2014) implemented multidisciplinary research initiatives aiming at assembling palaeoclimate data from the Holocene through recent field programmes in the Nordic Seas, and at integrating palaeoclimate information with modern biological and climate modelling data. Associated objectives were to recruit and train a new generation of European polar scientists with expertise on the Nordic Seas, and to develop a network of European experts in polar research to build structures focused on long-term collaboration in Arctic science. Together with the Arctic Ocean, the Nordic Seas and the Barents Sea have shown unprecedented changes in physical and chemical conditions in recent decades, which directly influence the ecosystem structure and processes. The extreme sensitivity of the northern North Atlantic to climate changes is related to the intricate connection, within this oceanic realm, of cryospheric (ice sheets and sea ice), atmospheric (winds related to strong gradients in sea-level pressures), and oceanic processes (through the opposing poleward flow of Atlantic water and southward flow of polar waters). The recent decline in seasonal sea ice extent is of particular concern as it modulates the reflection of incoming solar radiation, and influences the exchanges of heat and moisture between the surface ocean and the atmosphere. Moreover, sea ice also plays a central role in the efficiency of shelf (brines) and deep ocean convection processes, thus influencing the climate on a global scale. Decadal to millennial scale reconstructions of Holocene climate and environments from archives, such as marine sediment cores, and from palaeoclimate modelling hold keys to a better evaluation of the magnitude and implications of the ongoing warming with regard to the full range natural variability of the climate system. This special issue addresses some of the key questions raised by the CASE project and related to the present polar amplification of climate change: -Is the present global warming and its amplification in the Arctic and Subarctic domains a unique event on the scale of the Earth recent history (last 10 000 years)? -How do past decadal-to centennial-scale natural climate changes, as recorded in marine sediments and ice cores, stand in the context of the present human-induced modulation of climate? -How did Holocene variability in key physical elements affect the structure and diversity of the planktonic ecosystem in the Arctic and Subarctic domains?
(Climate of the Past. vol. 10, n° 1814-9324, pp. 589-590, 23/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UvA, LMD, INSU - CNRS, X, IP Paris, ENPC, SU, CNRS, ENS-PSL, PSL
Developmental toxicity of PAH mixtures in fish early life stages. Part I: adverse effects in rainbow trout
A new gravel-contact assay using rainbow trout, Oncorhynchus mykiss, embryos was developed to assess the toxicity of polycyclic aromatic hydrocarbons (PAHs) and other hydrophobic compounds. Environmentally realistic exposure conditions were mimicked with a direct exposure of eyed rainbow trout embryos incubated onto chemical-spiked gravels until hatching at 10 °C. Several endpoints were recorded including survival, hatching delay, hatching success, biometry, developmental abnormalities, and DNA damage (comet and micronucleus assays). This bioassay was firstly tested with two model PAHs, fluoranthene and benzo[a]pyrene. Then, the method was applied to compare the toxicity of three PAH complex mixtures characterized by different PAH compositions: a pyrolytic extract from a PAH-contaminated sediment (Seine estuary, France) and two petrogenic extracts from Arabian Light and Erika oils, at two environmental concentrations, 3 and 10 μg g−1 sum of PAHs. The degree and spectrum of toxicity were different according to the extract considered. Acute effects including embryo mortality and decreased hatching success were observed only for Erika oil extract. Arabian Light and pyrolytic extracts induced mainly sublethal effects including reduced larvae size and hemorrhages. Arabian Light and Erika extracts both induced repairable DNA damage as revealed by the comet assay versus the micronucleus assay. The concentration and proportion of methylphenanthrenes and methylanthracenes appeared to drive the toxicity of the three PAH fractions tested, featuring a toxic gradient as follows: pyrolytic < Arabian Light < Erika. The minimal concentration causing developmental defects was as low as 0.7 μg g−1 sum of PAHs, indicating the high sensitivity of the assay and validating its use for toxicity assessment of particle-bound pollutants.
(Environmental Science and Pollution Research. vol. 21, n° 0944-1344, pp. 13720-13731, 23/04/2026)
UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPGP, INRA, Biosit : Biologie - Santé - Innovation Technologique, BE, IFREMER
Technical, economic and environmental evaluation of advanced tertiary treatments for micropollutants removal (oxidation and adsorption)
Two pilots for tertiary treatment, an advanced oxidation processes (AOP - O3/UV/H2O2) pilot and a granular activated carbon pilot, were tested in three different wastewater treatment plants after a secondary treatment. A total of 64 micropollutants including drugs, pesticides, alkylphenols, PAHs and metals were analysed in the samples at the inlet and the outlet of the pilots. The tertiary treatments studied (ozone, AOP and activated carbon) were efficient for the removal of most of the compounds analysed in this study, except metals. The addition of hydrogen peroxide to ozone increased the number of substances well removed but it did not improve the removal of substances that readily react with ozone (such as betablockers or carbamazepine). The other AOP (ozone/H2O2 and UV/H2O2) did not improve the number of substances well removed in comparison with ozone alone. The granular activated carbon was still efficient (R>70%) after 6 months working 24/7 for most of the drugs and the urea and triazine pesticides. The 5 technologies studied were sized at full scale in order to calculate their cost for two sizes of WWTP. The implementation of a tertiary treatment on a 60 000 to 200 000 PE WWTP would increase the wastewater treatment cost by 1,5 to 17,6 euros cents per cubic meter treated according to the technology and the removal objective. Concerning the environmental impact, for the big WWTP, the activated carbon is more impacting than the other processes for most of the impacts calculated. The order of POA by increasing environmental impact is ozone < ozone/H2O2 < ozone/UV ~ UV/H2O2. For the medium size WWTP however, the activated carbon is comparable to the other solutions regarding environmental impact.
(pp. 4 p., 23/04/2026)
CIRSEE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA
Impact of precession on the climate, vegetation and fire activity in southern Africa during MIS4
The relationships between climate, vegetation and fires are a major subject of investigation in the context of climate change. In southern Africa, fire is known to play a crucial role in the existence of grasslands and Mediterranean-type biomes. Microcharcoal-based reconstructions of past fire activity in that region have shown a tight correlation between grass-fueled fires and the precessional cycle, with maximum fire activity during maxima of the climatic preces-sion index. These changes have been interpreted as the result of changes in fuel load in response to precipitation changes in eastern southern Africa. Here we use the general circulation model IPSL_CM5A (Institut Pierre Simon Laplace Climate Model version 5A) and the dynamic vegetation model LPJ-LMfire to investigate the response of climate, vegetation and fire activity to precession changes in southern Africa during marine isotopic stage 4 (74–59 kyr BP). We perform two climatic simulations, for a maximum and minimum of the pre-cession index, and use a statistical downscaling method to increase the spatial resolution of the IPSL_CM5A outputs over southern Africa and perform high-resolution simulations of the vegetation and fire activity. Our results show an anticorre-lation between the northern and southern African monsoons in response to precession changes. A decrease of the preces-sion climatic index leads to a precipitation decrease in the summer rainfall area of southern Africa. The drying of climate leads to a decrease of vegetation cover and fire activity. Our results are in qualitative agreement with data and confirm that fire activity in southern Africa during MIS4 is mainly driven by vegetation cover.
(Climate of the Past. vol. 10, n° 1814-9324, pp. 1165-1182, 23/04/2026)
PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPSL, ENS-PSL, PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, IP Paris, CNES, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CLIM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Impact of dietary cadmium sulphide nanoparticles on Danio rerio zebrafish at very low contamination pressure.
: Abstract To address the impact of cadmium sulphide nanoparticles (CdSNPs) of two different sizes (8 and 50 nm), Danio rerio zebrafish were dietary exposed to very low doses: 100 or 40 ng CdSNPs/day/g body weight for 36 or 60 days, respectively. The results obtained using RAPD-PCR genotoxicity test showed genomic alteration since the number of hybridisation sites of the RAPD probes was significantly modified after CdSNPs exposure. In addition, selected stress response genes were either repressed or upregulated in tissues of CdSNPs-exposed fish. Mitochondrial dysfunction was also caused by the presence of CdSNPs in food. Cadmium accumulation in fish tissues (brain and muscles) could only be observed after 60 days of exposure. CdSNPs toxicity was dependent on their size and concentration.
(Nanotoxicology. vol. 8, n° 1743-5390, pp. 676-685, 23/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ICMCB, UB, INC-CNRS, CNRS, IBGC, UB, CNRS
Inkjet coplanar square monopole on flexible substrate for 60-GHz applications
In this letter, the design, fabrication, and measurement of a 60-GHz printed antenna with inkjet technology over a flexible substrate is presented. The antenna is a coplanar square monopole with omnidirectional radiation characteristics. We especially measured a 68% total efficiency and a maximum realized gain of 1.8 dBi. This study demonstrates the inkjet technology being a competitive solution for efficient radiating elements at millimeter- wave frequencies.
(IEEE Antennas and Wireless Propagation Letters. vol. 13, n° 1536-1225, pp. 435-438, 23/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ST-CROLLES, IEMN, UVHC, CNRS, UPHF, LEAT, UNS, CNRS, UniCA, IUF, M.E.N.E.S.R.
Cartographie des habitats naturels des estrans et zones humides littorales
A l’interface entre terre et mer, les zones humides littorales sont des environnements dont le fonctionnement écosystémique est contraint par les forçages climatiques et anthropiques. Par le biais des directives européennes et des plans de gestion, ces milieux sont suivis et cartographiés à échéance régulière dans le but d’asseoir leur état écologique. Différentes stratégies de cartographie basées sur l’exploitation d’images satellite sont adoptées selon les objectifs à atteindre : (1) cartographie exhaustive des faciès/habitats intertidaux (type Natura 2000), (2) cartographie de l’herbier à Zostera noltii (Directive Cadre sur l’Eau), (3) cartographie des habitats des prés-salés, (4) suivi de l’évolution naturelle des paysages et de la végétation en lien avec des événements accidentels ou volontaires (actions de dépoldérisation). Cet article dresse un panorama des stratégies de cartographie exploitant des données optiques et radar à Haute (SPOT-5) et Très Haute Résolution Spatiale (Pléiades, TerraSAR-X) mises au point pour répondre aux besoins d’observation et d’expertise pour la gestion intégrée des milieux littoraux lagunaires.
(Revue Française de Photogrammétrie et de Télédétection. vol. 208, n° 1768-9791, pp. 51-56, 23/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR TETIS, Cirad, IRSTEA, CESBIO, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, INRAE, UB, ULR
A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum
(Quaternary Science Reviews. vol. 100, n° 0277-3791, pp. 1 - 9, 23/04/2026)
GCU, BAS, NERC, UGent, LGP, UP1, UPEC UP12, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IWF, OeAW, USF, CAM, DGES, LOCEAN, IPSL, ENS-PSL, PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, IP Paris, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, ULaval, INSU - CNRS, CNRS, PSI, NIFS, LDEO
Etude intégrée de l’effet des apports amont et locaux sur le fonctionnement de la Garonne estuarienne (ETIAGE) : Rapport de synthèse année 4 Avril 2013 - Mars 2014
Le programme ETIAGE a été mis en place avec pour objectif de répondre aux questions suivantes : que représentent les apports des effluents de la Communauté Urbaine de Bordeaux (CUB) par rapport à ceux venant de l’amont en termes de charge organique et de micro-polluants ? Quels rôles sur le devenir des effluents jouent la présence du bouchon vaseux et la stagnation résiduelle des eaux (déplacement net entre mouvement de flot et de jusant) au niveau de l’estuaire fluvial amont en période d’étiage estival ? Réciproquement, à quels moments et jusqu’où s’étend l’impact de ces effluents sur la qualité des eaux de la Garonne estuarienne ? Quelles incidences des effluents sur le comportement des populations biologiques en place ou migratoires dans la Garonne estuarienne ? Quelle tendance évolutive va connaître l’oxygénation des eaux ? Quel sera l’impact sur le comportement des micro-polluants et des populations biologiques ? Quelles recommandations de gestion pourraient être préconisées à partir de la synthèse des pressions exercées sur les eaux de la Garonne estuarienne ? Le programme est divisé en 5 axes, dont les bilans de travail sont présentés axe par axe.
(pp. 76, 23/04/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS