Video Monitoring and Field Measurements of a Rapidly Evolving Coastal System: the River Mouth and Sand Spit of the Mataquito River in Chile
The understanding of morphological processes controlling the evolution of sand spit reformation after a tsunami impact is a challenging and interesting topic, especially in highly energetic and micro tidal environments. A field campaign performed during December 2012 at the Mataquito River mouth in Chile, allowed us to simultaneously monitor topo-bathymetry evolution, wave climate, tidal range, swash zone dynamics and upper beach face evolution over a portion of its sand spit. A video system was set up for a continuous and long-term monitoring of the evolution of the river mouth and sand spit. Primarily, in this work we focus on the application of a video-derived shoreline detection method to assess shoreline evolution and beach cusps migration at hourly scales. We test the method performance on short-term episodic migration of beach cusps recorded during the campaign. Beach face variations at a daily scale were observed, which can be attributed to the migration of beach cusps in the alongshore direction, and linked to wave forcing and alongshore sediment transport.
(Journal of Coastal Research. vol. SI 70, n° 0749-0208, pp. 639-644, 30/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOLA, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
Morphodynamic characterisation of the human-impacted Bight of Benin sand barrier coast, West Africa
(Journal of Coastal Research. vol. SI 70, n° 0749-0208, pp. 079-083, 30/08/2026)
CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, ECOLA, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, OLVAC, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
Beach cusp dynamics on a reflective beach
Beach cusps are common feature of steep reflective and intermediate beaches. However very few observations reported double coupled cusp systems. Here we present a data set of observations of a beach exhibiting two sets of beach cusps. Data were collected at Grand Popo Beach (Benin, West Africa) in February 2013. Daily topographic survey along a 380m long stretch of shore allowed observing the dynamic of the two set of beach cusps. At the beginning of the field survey, we clearly observe two sets of cusps : the upper beach cusps system is relatively asymetric with a typical wavelength of about 45 m while the lower beach cusps system is relatively symmetric with a typical wave length slightly shorter (about 35 m). After two days, we measured the total destruction of the lower set of beach cusps while the upper set of beach cusps was only partially des tructed. Data suggest that destruction of the lowerbeach cusp system may be related to persistent accretions conditions and/or calm conditions but probably also to the transition from wave- driven circulation dominated by weak alongshore currents with flash and swash rips, to a second period characterized by dominant longshore current further increasing in speed, and rare swash rips. On the other hand the disappearance of the western upper beach cusp might be related to an accretion pattern and to the merging of two individual features. Our observations, consistent with previous works, suggest that beach cusps certainly arise as a result of some combination of erosion and accretion.
(Journal of Coastal Research. vol. SI 70, n° 0749-0208, pp. 669-674, 30/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOLA, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, UAC
The Grand Popo experiment, Benin
The first large nearshore field experiment in the G ulf of Guinea was conducted at Grand Popo Beach, Be nin, in February 2013, on an open wave-dominated micro- to meso-tidal coast, located mid-way between Cotonou and Lome harbours. The overall project aims at understanding at multi-scale (from event to interannual) the causes of the dramatic erosion observed throughout the Bight of Benin, and caused by the interaction of a large littoral drift with human engineering works. Grand Popo 2013 experiment was designed to measure the processes over the short term and to test the ability of an installed video system to monitor the evolution of this stretch of coast over the longer term. The beach, characterized by a low-tide terrace and a high tide reflective part, experiences a long swell (Hs=1.6m, Tp=16 s, oblique incidence ~15-20°). Topographic surveys showed a double beach cusp system interaction and repeated surf-zone drifter runs revealed high flash and swash rip activity driven by wave dissipation over the terrace and energetic swash dynamics at the upper reflective beach. Swash was measured over a cusp system at two locations using video poles. Wave reanalyses (ERAInterim) were used to determine the wave climate and its variability, and to quantify sediment transport. This robust methodology is thought to be replicated elsewhere in different coastal environments in West Africa, in particular with the objective to monitor various sites within the framework of the new West African Coastal Observatory.
(Journal of Coastal Research. vol. SI 70, n° 0749-0208, pp. pp. 651-656, 30/08/2026)
ECOLA, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, UAC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, IRD [France-Ouest], OLVAC, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
Abnormal ovarian DNA methylation programming during gonad maturation in wild contaminated fish
There is increasing evidence that pollutants may cause diseases via epigenetic modifications. Epigenetic mechanisms such as DNA methylation participate in the regulation of gene transcription. Surprisingly, epigenetics research is still limited in ecotoxicology. In this study, we investigated whether chronic exposure to contaminants experienced by wild female fish (Anguilla anguilla) throughout their juvenile phase can affect the DNA methylation status of their oocytes during gonad maturation. Thus, fish were sampled in two locations presenting a low or a high contamination level. Then, fish were transferred to the laboratory and artificially matured. Before hormonal treatment, the DNA methylation levels of the genes encoding for the aromatase and the receptor of the follicle stimulating hormone were higher in contaminated fish than in fish from the clean site. For the hormone receptor, this hypermethylation was positively correlated with the contamination level of fish and was associated with a decrease in its transcription level. In addition, whereas gonad growth was associated with an increase in DNA methylation in fish from the clean site, no changes were observed in contaminated fish in response to hormonal treatment. Finally, a higher gonad growth was observed in fish from the reference site in comparison to contaminated fish.
(Environmental Science and Technology. vol. 48, n° 0013-936X, pp. 11688--11695, 30/08/2026)
µVIS X-ray Imaging Centre, LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EABX, IRSTEA, ISM, UB, INC-CNRS, CNRS, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, INRS
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, 30/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UvA, LMD, INSU - CNRS, X, IP Paris, ENPC, SU, CNRS, ENS-PSL, PSL
Tectonics of the Dalrymple Trough and uplift of the Murray Ridge (NW Indian Ocean)
The Dalrymple Trough is a 150-km-long, 30-km-wide basin located at the northern termination of the Owen Fracture Zone (OFZ), which is the present-day active India-Arabia plate boundary. The Dalrymple Trough is closely associated with the Murray Ridge, a complex of prominent bathymetric highs located on its eastern flank. Recent multibeam mapping of the connection between the Dalrymple Trough and the OFZ revealed a horsetail structure, which suggests a close relationship between geological histories of both structures. However, the 3-6 Ma age of initiation of the OFZ contrasts with the commonly accepted Early Miocene emplacement of the Dalrymple Trough. Recent seismic lines document a new tectonic history of the Dalrymple Trough, involving two major episodes of deformation along the India-Arabia plate boundary at ~ 8-10 Ma and ~ 1.9 ± 0.9 Ma. The 8-10 Ma episode is marked by a system of folds linked to the main uplift of the southern Murray Ridge and the first uplift of the northern Murray Ridge. This episode is related to a global plate reorganization event in the Late Miocene, well expressed by intraplate deformation in the Central Indian Ocean. The Dalrymple Trough opened at ~ 1.9 ± 0.9 Ma subsequently to the formation of a stepover at the India-Arabia plate boundary, coeval with the regional M-unconformity in the Oman abyssal plain, which marks a structural reorganization of the Makran accretionary wedge, and the last uplift of the northern Murray Ridge.
(Tectonophysics, n° 0040-1951, pp. 1-49, 30/08/2026)
LGENS, INSU - CNRS, CNRS, ENS-PSL, PSL, iSTeP, UPMC, CNRS, GEC, I-MAT, UCP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
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, 30/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEODE, UT2J, Comue de Toulouse, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France]
Hypoxia tolerance of European sturgeon (Acipenser sturio L., 1758) young stages at two temperatures
European sturgeon sensitivity to oxygen depletion at two different temperatures was evaluated with embryos from fertilization to hatching time that were exposed to 90% O2 saturation (% O2 sat), 50% O2 sat and 30% O2 sat at 20 and 26°C; and three-month-old juveniles (12 cm length, 7.3 g width) exposed to oxygen challenge from 70% O2 sat to 10% O2 sat at 20 and 25°C. Parameters measured included embryonic survival rate (ESR) and hatch rate (HR); in juvéniles the opercular beat frequency (OBF), altered swimming behavior, loss of equilibrium (LOE), and death were recorded. ESR did not differ between oxygen saturation levels for a single temperature but decreased between 20 and 26°C from 60.7 to 21.4% mean survival, respectively. No hatching was observed in embryos exposed to oxygen depletion at 50 and 30% O2 sat, regardless of temperature. The HR was lower at 26°C (15.4% mean) than at 20°C (75.8%) at 90% O2 sat. In embryos, all three oxygen concentrations allowed embryonic survival at the tested temperatures but were insufficient for increased activity such as hatching except at 20°C and 90% O2 sat. In juveniles, OBF peaked at 40% O2 sat at 212 beats per minute at 25°C and at 40–30% O2 sat at 182–183 beats per minute at 20°C. For LOE and death no significant differences were observed with regard to oxygen saturation at 20 and 25°C. Altered swimming behavior appeared at a significantly higher oxygen saturation at 25°C (43.5%) compared to 20°C (34.5%). Anaerobic metabolism was initiated after the OBF peak, which would represent a PO2crit for European sturgeon juveniles under 30 and 40% at 20°C and 25°C, respectively. Temperature increase also adversely affected the threshold of altered swimming behavior, which could be considered as a behavioral indicator of metabolic stress. The probability that the sturgeon embryos are being exposed to harmful temperatures and hypoxic conditions remains a true threat in the Gironde catchment basin.
(Journal of Applied Ichthyology. vol. 30, n° 0175-8659, pp. 1195-1202, 30/08/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Multi-criteria assessment of advanced tertiary treatments for micropollutants removal
This paper presents the removal of 64 micropollutants from wastewater by 5 tertiary treatment processes: adsorption on activated carbon, ozone, ozone/H2O2, ozone/UV and UV/H2O2. Several validated analytical methods were used and reached very low limits of quantification (ng/L) and limited uncertainties. The tertiary treatments studied in the conditions applied were found efficient for the removal of most of the compounds analyzed in this study, except metals. Activated carbon and ozone allowed the removal over 70% of 2/3 of the organic micropollutants quantified. The addition of hydrogen peroxide to ozone increased the number of substances well removed (Rw>70%), but it did not improve the removal of substances that readily react with ozone. The other AOP (ozone/H2O2 and UV/H2O2) did not improve the number of substances well removed in comparison with ozone alone. The 5 technologies studied were sized at full scale in order to evaluate their investment and operation costs for two sizes of WWTP. According to this study, the implementation of a tertiary treatment on a 60 000 or a 200 000 PE WWTP would increase the water treatment cost by 2 to 20 euros cents per cubic meter treated according to the technology, the list of analyzed compounds and the removal objective.
(pp. 4, 30/08/2026)
IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA