NW France Research Articles

Striking forest revival at the end of the Roman Period in north-western Europe

The Holocene period (last 11,700 years BP) has been marked by significant climate variability over decadal to millennial timescales. The underlying mechanisms are still being debated, despite ocean–atmosphere–land connections put forward in many paleo-studies. Among the main drivers, involving a cluster of spectral signatures and shaping the climate of north-western Europe, are solar activity, the North Atlantic Oscillation (NAO) varying atmospheric regimes and North Atlantic oceanic gyre dynamics. Over the last 2500 years BP, paleo-environmental signals have been strongly affected by anthropogenic activities through deforestation and land use for crops, grazing, habitations, or access to resources. Palynological proxies (especially pollen grains and marine or freshwater microalgae) help to highlight such anthropogenic imprints over natural variability. Palynological analyses conducted in a macro-estuarine sedimentary environment of north-western France over the last 2500 years BP reveal a huge and atypical 300 year-long arboreal increase between 1700 and 1400 years BP (around 250 and 550 years AD) that we refer to as the ‘1.7–1.4 ka Arboreal Pollen rise event’ or ‘1.7–1.4 ka AP event’. Interestingly, the climatic 1700–1200 years BP interval coincides with evidence for the withdrawal of coastal societies in Brittany (NW France), in an unfavourable socio-economic context. We suggest that subpolar North Atlantic gyre strengthening and related increasing recurrence of storminess extremes may have affected long-term coastal anthropogenic trajectories resulting in a local collapse of coastal agrarian societies, partly forced by climatic degradation at the end of the Roman Period.

Lower Cambrian facies architecture and sequence stratigraphy, NW France: framework for evaluation of basin-wide processes of sedimentation

AbstractA correlation and interpretation of the sequence stratigraphy of the lower Cambrian strata of NW France is presented and used to characterize basin-wide controls on processes of sedimentation. Deposition occurred in two basins, as two third-order stratigraphic sequences. A northern basin in the Cotentin was dominated by deposition of marine siliciclastic sediments of Sequence 1 (Cambrian Stages 2–3). The primary sediment input was from the NW at La Hague. A middle Normandy basin, SW of Caen, was characterized by deposition of platform carbonates and fine-grained, offshore siliciclastics in Sequence 1 and fluvio-deltaic and marine siliciclastics in Sequence 2 (Cambrian Stages 3–4). Major sediment input points lay to the west in Brittany and to the NE of Caen (in Sequence 2). Lowstand and transgressive systems tract strata dominate both sequences, with local preservation of highstand deposits in basin-centre locations. Fluvial deposits occur at basin margins and display sandstone-dominated facies typical of prevegetation systems. Two styles of fluvially dominated siliciclastic delta are recognized, which show delta-front strata composed of fluvial channels overlying either wave-formed deposits or hyperpycnites. The former formed on shallow shelves, whereas the latter formed where basin bathymetry was steeper and commonly fault controlled. Fossil microbial life forms are conspicuous in Sequence 1, as are intervals of low-diversity bioturbation. The balance of life forms is consistent with the punctuated replacement of algal matgrounds with mixgrounds during early Cambrian time. Super-mature quartz arenites were formed by high-energy wave processes on slowly aggrading basin flanks following marine transgression.

Effects of Global Climate Oscillations on Intermonthly to Interannual Variability of Sea levels along the English Channel Coasts (NW France)

Summary This work examines the multiscale variability in sea level along the English Channel coasts (NW France) using a wavelet multiresolution decomposition of water level values and climate oscillations in order to gain insights in the connection between the global atmospheric circulation and the local-scale variability of the monthly extreme surges. Changes in surges have exhibited different oscillatory components from the intermonthly (∼3–6-months) to the interannual scales (∼1.5-years, ∼2–4-years, ∼5–8-years) with mean explained variances of ∼40% and ∼25% of the total variability respectively. The correlation between the multiresolution components of surges and 28 exceptional stormy events with different intensities has revealed that energetic events are manifested at all timescales while moderate events are limited to short scales. By considering the two hypotheses of (1) the physical mechanisms of the atmospheric circulation change according to the timescales and (2) their connection with the local variability improves the prediction of the extremes, the multiscale components of the monthly extreme surges have been investigated using four different climate oscillations (Sea Surface Temperature (SST), Sea-Level Pressure (SLP), Zonal Wind (ZW), and North Atlantic Oscillation (NAO)); results show statistically significant correlations with ∼3–6-months, ∼1.5-years, ∼2–4-years, and ∼5–8-years, respectively. Such physical links, from global to local scales, have been considered to model the multiscale monthly extreme surges using a time-dependent Generalized Extreme Value (GEV) distribution. The incorporation of the climate information in the GEV parameters has considerably improved the fitting of the different timescales of surges with an explained variance higher than 30%. This improvement exhibits their nonlinear relationship with the large-scale atmospheric circulation.

Congruence between fine-scale genetic breaks and dispersal potential in an estuarine seaweed across multiple transition zones

AbstractGenetic structure in biogeographical transition zones can be shaped by several factors including limited dispersal across barriers, admixture following secondary contact, differential selection, and mating incompatibility. A striking example is found in Northwest France and Northwest Spain, where the estuarine seaweed Fucus ceranoides L. exhibits sharp, regional genetic clustering. This pattern has been related to historical population fragmentation and divergence into distinct glacial refugia, followed by post-glacial expansion and secondary contact. The contemporary persistence of sharp ancient genetic breaks between nearby estuaries has been attributed to prior colonization effects (density barriers) but the effect of oceanographic barriers has not been tested. Here, through a combination of mesoscale sampling (15 consecutive populations) and population genetic data (mtIGS) in NW France, we define regional genetic disjunctions similar to those described in NW Iberia. Most importantly, using high resolution dispersal simulations for Brittany and Iberian populations, we provide evidence for a central role of contemporary hydrodynamics in maintaining genetic breaks across these two major biogeographic transition zones. Our findings further show the importance of a comprehensive understanding of oceanographic regimes in hydrodynamically complex coastal regions to explain the maintenance of sharp genetic breaks along continuously populated coastlines.

Evolution of a Shelly Beach Ridge System over the Last Decades in a Hypertidal Open-coast Embayment (Western Mont-Saint-Michel Bay, NW France)

Tessier, B.; Poirier, C.; Weill, P.; Dezileau, L.; Rieux, A.; Mouaze, D.; Fournier, J., and Bonnot-Courtois, C., 2019. Evolution of a shelly beach ridge system over the last decades in a hypertidal open-coast embayment (western Mont-Saint-Michel Bay, NW France). In: Castelle, B. and Chaumillon, E. (eds.), Coastal Evolution under Climate Change along the Tropical Overseas and Temperate Metropolitan France. Journal of Coastal Research, Special Issue No. 88, pp. 77–88. Coconut Creek (Florida), ISSN 0749-0208.The behavior of the shelly beach ridge system forming a more or less continuous barrier lying along the southern coast of the hypertidal Mont-Saint-Michel bay (NW France) is examined using a set of various data including aerial photographs since 1947, sediment cores collected in back-barrier salt marshes, ground penetrating radar profiles, and differential digital elevation models (DEMs). The latter shows that since the middle of the 20th century, the tidal flats extending in front of the ridge system experience erosion and accretion that alternate spatially according to cross-shore corridors. The shelly ridges are better developed on line with the erosional bands. The reasons for this erosion/accretion compartment pattern are not totally elucidated. It probably results from the combined influence of shellfish farms, tidal channels and reef present on the tidal flats on wave and current dynamics. At the decadal to pluri-decadal scale, the shelly beach ridge system behavior as well as its internal organization can partly be related to the fluctuations of hydrodynamic conditions controlled by the 18.6 years nodal tidal cycle. Periods of intense landward migration alternate with periods of relative stability during the peak and the trough of the cycle respectively. This general scheme is complicated due to variations in storm wave dynamics. The most morphogenic events happen potentially during coinciding nodal cycle peaks and enhanced storminess. Such conditions actually occurred around 1995-2000, resulting in the most prominent washover fan deposit preserved within the back-barrier infilling successions. These sediment successions evidence as well that no beach ridge system older than the 19th century is preserved in front of the Medieval dike built during the 11th century on a relict beach ridge, and on which the present-day system is backed. We suggest that the enhanced storminess conditions of the Little Ice Age provoked the reworking of beach ridges formed between the 11th and 19th centuries. Changes in quantity and type of mollusk shells, related to the shellfish farming development during the 20th century are also thought to have had positive consequences on the barrier building and stability.

The potential of Pléiades images with high angle of incidence for reconstructing the coastal cliff face in Normandy (France)

To monitor chalk cliff face along the Normandy coast (NW France) which is prone to erosion, we tested the potential of cliff face 3D reconstruction using pairs of images with high angle of incidence at different dates from the agile Pléiades satellites. The verticality aspect of the cliff face brings difficulties in the 3D reconstruction process. Furthermore, the studied area is challenging mainly because the cliff face is north-oriented (shadow). Pléiades images were acquired over several days (multi-date stereoscopic method) with requested incidence angles until 40°. 3D reconstructions of the cliff face were compared using two software: ASP® and ERDAS IMAGINE®. Our results are twofold. Firstly, despite ASP® provides denser point clouds than ERDAS IMAGINE® (an average of 1.60 points/m² from 40° incidence angle stereoscopic pairs on the whole cliff face of Varengeville-sur-Mer against 0.77 points/m² respectively), ERDAS IMAGINE® provides more reliable point clouds than ASP® (precision assessment on the Varengeville-sur-Mer cliff face of 0.31 m ± 2.53 and 0.39 m ± 4.24 respectively), with a better spatial distribution over the cliff face and a better representation of the cliff face shape. Secondly, the quality of 3D reconstructions depends mostly on the amount of noise from raw images and on the shadow intensity on the cliff face (radiometric quality of images).

Regional patterns in medieval European glass composition as a provenancing tool

A legacy dataset of 1329 major element analyses of medieval glass (12th-15th centuries) has been compiled and analysed for geographical distribution of compositional characteristics. Three regional compositional types may be distinguished using simple elemental plots, associated with glass production in northwestern France, in the region around the Rhine, and in central Europe. Distribution maps are presented to aid interpretation and use of the data. The application of the approach is illustrated through three case studies. Late thirteenth-early fourteenth century medieval stained glass from York Minster (n = 91), late fourteenth-century stained glass from New College Oxford (n = 79) and a single medieval mirror found in Egypt were analysed using scanning electron microscopy–energy dispersive analysis. The York coloured and white glasses were identical and consistent with an origin in NW France. In the late fourteenth century, the coloured glass samples from Oxford were from the Rhenish region, while the white glass is consistent with an origin in NW France or England. The mirror glass from Egypt is of central European origin, and similar mirror glass is known from Italy. The apparent dominance of German mirror production may reflect an advantage of the glass, which is low in iron. The meta-analysis of the legacy data shows significant potential for developing an understanding of the production and movement of medieval glass.

On biotic and abiotic drivers of the microphytobenthos seasonal cycle in a temperate intertidal mudflat: a modelling study

Abstract. Microphytobenthos (MPB) from intertidal mudflats are key primary producers at the land–ocean interface. MPB can be more productive than phytoplankton and sustain both benthic and pelagic higher trophic levels. The objective of this study is to assess the contribution of light, mud temperature, and gastropod Peringia ulvae grazing pressure in shaping the seasonal MPB dynamics on the Brouage mudflat (NW France). We use a physical–biological coupled model applied to the sediment first centimetre for the year 2008. The simulated data compare to observations, including time-coincident remotely sensed and in situ data. The model suggests an MPB annual cycle characterised by a main spring bloom, a biomass depression in summer, and a moderate fall bloom. In early spring, simulated photosynthetic rates are high due to mud surface temperature (MST) values close to the MPB temperature optimum for photosynthesis and because increasing solar irradiance triggers the onset of the MPB spring bloom. Simulated peaks of high P. ulvae grazing (11 days during which ingestion rates exceed the primary production rate) mostly contribute to the decline of the MPB bloom along with the temperature limitation for MPB growth. In late spring–summer, the MPB biomass depression is due to the combined effect of thermo-inhibition and a moderate but sustained grazing pressure. The model ability to infer biotic and abiotic mechanisms driving the seasonal MPB dynamics could open the door to a new assessment of the export flux of biogenic matter from the coast to the open ocean and, more generally, of the contribution of productive intertidal biofilms to the coastal carbon cycle.

A new species of the haematophagous genus Austroconops Wirth & Lee (Diptera: Ceratopogonidae: Leptoconopinae) from middle Cretaceous amber of Charente-Maritime, France

Austroconops perrichoti, a new species of biting midge (Diptera: Ceratopogonidae), is described from uppermost Albian-lowermost Cenomanian amber of Charente-Maritime (NW France), from three female specimens. A similar species, Austroconops borkenti Szadziewski & Schlüter, 1992, from Upper Cretaceous, Cenomanian, French amber of Anjou, is redescribed and illustrated. A key to males and females of extinct species of Austroconops Wirth & Lee is also provided.

First evidence of Ediacaran–Fortunian elliptical body fossils in the Brioverian series of Brittany, NW France

Body fossils are described for the first time from the Upper Brioverian (Ediacaran-Fortunian) deposits of Central Brittany (NW France). The material consists of a dozen of specimens preserved on two slates, recently collected in a quarry in Saint-Gonlay. The fossils, centimetric in size, have an elliptical and acuminated outline, with a peripheral bulge but without conspicuous concentric or radial lines. These body fossils are preserved in slates that are locally rich in grazing traces, sometimes associated with microbial mats. The sedimentological characteristics of these deposits correspond to a shallow marine shelf environment, with a low to moderate hydrodynamism. Such findings, in concomitance with previous ichnological discoveries, unravel the potential of the Brioverian strata from Brittany as a new locality to provide answers on Ediacaran and early Cambrian biocenoses.

Human-induced river runoff overlapping natural climate variability over the last 150 years: Palynological evidence (Bay of Brest, NW France)

Abstract For the first time a very high resolution palynological study (mean resolution of 1 to 5 years) was carried out over the last 150 years in a French estuarine environment (Bay of Brest; NW France), allowing direct comparison between the evolution of landscapes, surface water, and human practices on Bay of Brest watersheds, through continental (especially pollen grains) and marine (phytoplanktonic microalgae: cysts of dinoflagellates or dinocysts) microfossils. Thanks to the small size of the watersheds and the close proximity of the depositional environment to the mainland, the Bay of Brest represents an ideal case study for palynological investigations. Palynological data were then compared to published palaeo-genetic analyses conducted on the same core and to various available instrumental data, allowing us to better characterize past environmental variability since the second half of the 19th century in Western Brittany. We provide evidence of some clues of recent eutrophication and/or pollution that affected phytoplankton communities and which appears linked with increased runoff (higher precipitations, higher percentages of riparian forest pollen, decline of salt marsh-type indicators, and higher values of the XRF Ti/Ca signal), mainly explained by the evolution of agricultural practices since 1945 superimposed on the warming climate trend. We assume that the significant relay observed between dinocyst taxa: Lingulodinium machaerophorum and Spiniferites bentorii around 1965 then followed by Spiniferites membranaceus after 1985, attests to a strong and recent eutrophication of Bay of Brest surface waters induced by high river runoff combined with abnormally elevated air temperatures, especially obvious in the data from 1990. The structure of the dinocyst community has thus been deeply altered, accompanied by an unprecedented increase of Alexandrium minutum toxic form at the same period, as confirmed by the genetic quantification. Despite this recent major anthropogenic forcing, the fossil pollen sequence also records natural climate variability. We highlight, for the first time, a possible connection between climate (AMO modes) and fossil pollen records (especially tree pollination rates) in coastal sediments using tree percentage fluctuations as an indirect proxy for past sea surface and atmospheric temperatures.

Palaeobotanical investigation of a Cenomanian clay lens in Hucheloup Quarry, Maine-et-Loire, NW France: Taxonomic, stratigraphic and palaeoenvironmental implications

A Cenomanian clay lens in Hucheloup Quarry (Maine-et-Loire, north-western France) has yielded 82 foliar compressions and impressions, of which 62 were identified at several taxonomic levels. The plants are ascribed to diverse Pinales (27%), ferns (27%), Ginkgoales (26%), angiosperms (19%) and Cycadales (1%). The most abundant species in the assemblage are Frenelopsis alata (K. Feistmantel) E. Knobloch emend. J. Kvaček (Pinales) and Eretmophyllum obtusum (Velenovský) J. Kvaček (syn. E. andegavense Pons, Bourreau et Broutin) (Ginkgoales). Wood fragments, along with very well-preserved cuticles, have also been recovered and identified. The specimens are usually very fragmentary, indicating that they had been transported over a significant distance before deposition. The Hucheloup clay was probably deposited in a brackish lagoon or in the lower part of an estuary, possibly in an abandoned channel or on a sandbar. The allochthonous flora represents at least two plant communities that developed in a subtropical–tropical climate, and along a salinity gradient in the vicinity of a fluvial network. Use of the fossil-genus Eretmophyllum Thomas emend. Harris in Harris et al. is considered to be the correct choice for ginkgoalean leaves within European Cenomanian deposits; the genus Nehvizdya Hluštík is regarded as a junior synonym. The clay lens has also yielded a palynological assemblage. Although lacking unequivocal indicators of this age and including some taxa that are more typical of older rocks, the composition of the associated, very small megaspore assemblage recovered is consistent with a Cenomanian determination.

A witness in the landscape: The bombing of the Forêt domaniale des Andaines and the Normandy Campaign, NW France, 1944

An archaeological survey of well-preserved Second World War German supply depots and bomb craters from Allied air raids in the Forêt domaniale des Andaines, Normandy, has prompted an evaluation of the effectiveness of Allied intelligence gathering and tactical bombing of the German logistics network in advance of, and during the Normandy Campaign of June–August 1944. In conjunction with analysis of primary German and Allied archive sources, published historical accounts and aerial photographs, we demonstrate that Allied intelligence knew of the importance of the forest as a major fuel depot and attacked it with at least 46 missions over the period 13 June–4 August. However, landscape evidence demonstrates that only one of three fuel depot sites in the forest was successfully identified and partially destroyed by bombing. Allied intelligence efforts also failed to gather sufficient evidence to target one of the largest Seventh Army munitions depots in Normandy. Supply depots in the forest thus remained operational until late in the campaign and will have supported the German Mortain counter-offensive of 7–14 August. The limited success of Allied bombing in the Forêt domaniale des Andaines testifies to the difficulties in striking well-dispersed and camouflaged woodland facilities and supports the argument that the success of air power against German logistics efforts lay primarily in the degradation of the regional communications infrastructure and the Wehrmacht’s vehicle fleet rather than the destruction of supply dumps.

High‐resolution mapping of soil phosphorus concentration in agricultural landscapes with readily available or detailed survey data

SummaryHigh‐resolution mapping of soil phosphorus (P) concentration is necessary to identify critical source areas reliably where a large risk of transport coincides with a large potential source of P in agricultural landscapes. However, dense soil P data are not usually available to produce such maps and to obtain them is expensive. In this study, we modelled and mapped soil extractable P (ExtP) and total P (TP) concentrations in an intensively farmed 12‐km2 catchment in Brittany (NW France) with two different datasets to test the suitability of readily available regional or national databases for high‐resolution mapping. We used a machine learning tool (Cubist) to develop rule‐based predictive models from a calibration dataset. Covariates included pedological, geological, agricultural, terrain and geophysical‐related attributes obtained specifically in the study area (SURVEY) or derived from readily available regional or national databases (DATABASE). Even though better predictions were obtained with the SURVEY data (RMSE = 0.018 g kg−1 for ExtP and RMSE = 0.219 g kg−1 for TP), the DATABASE data produced acceptable predictions (RMSE = 0.024 g kg−1 for ExtP and RMSE = 0.253 g kg−1 for TP). The machine learning tool helped to identify key covariates that would improve the prediction of soil P when detailed data are not available. Readily available data about crop rotations could increase the accuracy of existing ExtP maps. These maps, combined with additional soil analysis for extractable Al, would improve the mapping of TP and the identification of areas with a large potential source of P.Highlights Modelling and mapping of soil phosphorus with the machine learning algorithm Cubist. Comparison of regional or national databases and detailed survey data for prediction. Models with regional and national data performed well, but some areas with large concentrations of P were not identified. Information about crop rotation and soil extractable Al improved model performance.

Trace Fossils from the Brioverian (Ediacaran–Fortunian) in Brittany (NW France)

ABSTRACTThe Ediacaran–Fortunian ichnofauna from Central Brittany (NW France) is revised for the first time since the pioneering work by Lebesconte at the end of the 19th century. The study is based on fossils from the type-localities of the historical Brioverian taxa Montfortia (traces from Montfort-sur-Meu) and Neantia (wrinkle surfaces from Néant-sur-Yvel), and on two new outcrops from Saint-Gonlay. The ichnofossil assemblage includes Helminthoidichnites tenuis, Helminthopsis tenuis, Gordia marina, Palaeophycus tubularis, ?Neonereites uniserialis, and ?Spirodesmos archimedeus. Locally, the grazing traces are associated with wrinkle surfaces considered as microbially induced sedimentary structures (MISS). The sedimentological characteristics of these deposits correspond to a shelf marine environment. Both U-Pb datings on detrital zircon and ichnostratigraphic criteria tend toward an Ediacaran age of the fossiliferous deposits, but we cannot exclude the possibility of a Fortunian age at the present state of knowledge.

Modern palynological record in the Bay of Brest (NW France): Signal calibration for palaeo-reconstructions

Modern palynological investigations (pollen and non-pollen palynomorphs) have been carried out for the first time in the entire Bay of Brest (BB; NW France), a semi-enclosed oceanic basin flooded during the Holocene that today is exposed to both marine (North Atlantic surface waters) and fluvial (Aulne and Elorn rivers) influences. Palynological analyses were conducted on 41 surface sediments collected in several mudded bays where low-energy conditions prevail, allowing for fine particle decantation, and also on 12 moss samples considered to be pollen rain collectors taken on the periphery of the BB. Furthermore, the BB allows a direct comparison between landscapes and fossilized pollen assemblages in sediments thanks to relatively small watersheds and well-studied vegetation cover on land. Our data display a well-known distortion between pollen taxa percentages calculated from palynological slides and current vegetation cover on land, with a particular overestimation of arboreal taxa as well as an underestimation of herbaceous ones, especially of cereal crops that represent a major component of the regional continental vegetation. Various factors may be involved, including pollen transport issues, taphonomic processes, and different pollination rates according to trees/herbaceous taxa. Under close examination, we find that while all surface sediments show the same major species, palynological maps established in the BB regarding some specific pollen taxa exhibit differences and upstream-downstream gradients. Also, the comparison between the pollen content in BB surface sediments and in mosses supports the hydrodynamic influence acting on the pollen distribution in sediments. More specifically, we suggest that some arboreal taxa reflect a watershed effect, especially Alnus, which seems to be highly correlated to river influences and could therefore be considered as a potential proxy for fluvial Holocene palaeo-discharges within the BB.

Seasonal variation and mixing behaviour of glutathione, thioacetamide and fulvic acids in a temperate macrotidal estuary (Aulne, NW France)

Fulvic acids and two dissolved reduced sulphur substances (RSS) were analysed for one year along the whole salinity gradient in the Aulne estuary (north-western France) using differential pulse cathodic stripping voltammetry. Concentrations of glutathione-like (GSH-like), thioacetamide-like (TA-like) and fulvic acid-like (FA-like) compounds ranged from 0.2 to 38 nmol L−1, from 0.02 to 6.6 μmol L−1 and from 0.1 to 4 mgC L−1, respectively. Our results indicated primarily allochthonous-continental sources for all three compounds. The behaviour of GSH-like compounds along the salinity gradient was globally conservative, with minor losses (<25%), possibly limited due to metal complexation. TA-like compounds generally displayed non-conservative behaviour with important removals. In terms of the TA-like budget, losses were counterbalanced by exceptional inputs occurring in the flood period (February). FA-like compounds were intensely degraded (∼50%) in the last section of the river and then behaved conservatively in the estuary. The annual flux of FA-like compounds to coastal waters was 2800 ± 600 tC. This flux was mainly (74%) delivered during the high discharge period, in accordance with its known pedogenic origin.

Spatio-temporal dynamics of per and polyfluoroalkyl substances (PFASs) and transfer to periphytic biofilm in an urban river: case-study on the River Seine.

This study addresses the spatio-temporal dynamics of per and polyfluoroalkyl substances (PFASs) in a highly urbanized freshwater hydrosystem, the Seine River (NW France). The distribution of PFASs between water, sediment, and periphytic biofilm was investigated at three sampling sites along a longitudinal gradient upstream and downstream from the Paris urban area. Seasonal variability was assessed through four sampling campaigns performed under contrasting hydrological conditions. In the dissolved phase, ∑PFASs fluctuated between 2 and 9ngL-1 upstream and 6-105ngL-1 downstream from Paris. Negative correlations between dissolved PFAS levels and river flow rate were generally observed, corroborating the predominance of point-source PFAS inputs at these sites. 18/19 target PFASs were detected, with a predominance of PFHxS and PFOS (20% of ∑PFASs each), except for the farthest downstream site where 6:2 FTSA was prevalent (35±8% of ∑PFASs), likely reflecting industrial and urban inputs. In biofilms, ∑PFASs fell in the 4-32ngg-1 dw range, and substantial bioconcentration factors (BCFs) were reported for PFNA, PFDA, and PFOS (log BCF 2.1-4.3), higher than those of PFHxS or PFOA. BCFs varied inversely with dissolved PFAS levels, potentially pointing to concentration-dependent bioaccumulation. Biofilm community characteristics (C/N ratio) may also be an influential determinant of PFAS bioaccumulation. Graphical abstract ᅟ.

Second World War bomb craters and the archaeology of Allied air attacks in the forests of the Normandie-Maine National Park, NW France

Well-preserved bomb craters in the forests of central Normandy, NW France, constitute archaeological legacies of combat inland from the D-Day beachheads that greatly extend the inventory of Second World War conflict landscapes in northwest Europe. Field survey and analysis of German and Allied documents demonstrates that bombscapes in the Forêt domaniale des Andaines and Forêt domaniale d'Ecouves reflect US Ninth Army Air Force attacks on a German fuel depot and radar installation, respectively, during June-August, 1944. One hundred and thirty-six craters are mapped, described and linked to specific air raids, bomb types and, for one raid on the 13th June, six specific participating aircraft and aircrews. These landscapes echo the impact of widespread tactical bombing against targets close to civilian population centers, and in some cases employing civilian and PoW labor. They are therefore well-placed to contribute to wider heritage narratives around the non-combatant experience of aerial warfare in WWII.

Becklesia maulnyi sp. nov.: A new cycadean species from the Lower Oxfordian (Upper Jurassic) of Écommoy (Sarthe, NW France)

Plant macrofossil remains of Becklesia Seward, 1895 emend. Watson and Cusack, 2005, a rare genus of extinct cycad, have been known for over a century from Great Britain and Libya. Historically the genus was poorly characterized leading to many fossil cycads that resembled Becklesia being placed in other genera including Cycadites and Paracycas. We describe here a new species, B. maulnyi sp. nov., from an exceptional and almost complete cycad specimen housed for two hundred years in the collections of the Musée Vert of Le Mans. The specimen comprises the apex of a stem bearing petiolate and pinnate leaves with thin and widely separated leaflets, which possess two prominent abaxial stomatal grooves that are characteristic of the genus Becklesia. We reassign three other French cycad fossils previously described under different generic names to Becklesia. Finally, we briefly discuss the geographical and stratigraphical implications of the genus and also consider presence of entire cycads in the fossil record.