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Here, we describe the full-length genome sequence of a novel potyvirus, tentatively named “Miscanthus sinensis mosaic virus” (MsiMV), isolated from Miscanthus sinensis (silver grass) held in a post-entry quarantine facility after being imported into Western Australia, Australia. The MsiMV genome is 9604 nucleotides (nt) in length, encoding a 3071-amino-acid (aa) polyprotein with conserved sequence motifs. The MsiMV genome is most closely related to that of sorghum mosaic virus (SrMV), with 74% nt and 78.5% aa sequence identity to the SrMV polyprotein region. Phylogenetic analysis based on the polyprotein grouped MsiMV with SrMV, sugarcane mosaic virus (SCMV), and maize dwarf mosaic virus (MDMV). This is the first report of a novel monopartite ssRNA virus in Miscanthus sinensis related to members of the genus Potyvirus in the family Potyviridae.

The transition to the Neolithic on the East European Plain was a very different process to the Western model, featuring a long-lasting hunter-gatherer economy and late introduction of agriculture. The authors present results from multiproxy research on a 13.5m-deep core of organic deposits from the Serteya mire as part of an international research project to understand human-environment relations in the Western Dvina Lakeland.

In the present paper, we describe how a robust and fundamental methodology was developed for extraction and determination of a principal natural toxin compound, simplexin, from a series of bulk biocomposites. These complex matrices were fabricated by direct encapsulating either ground plant particles or an ethanolic crude extract of the Australian toxic pasture plant Pimelea trichostachya in the biodegradable polymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Proton nuclear magnetic resonance spectroscopy was initially employed to examine the chemical compositions of these complicated systems. Then, a more sensitive strategy was developed and validated by combining solid-phase extraction and ultrahigh-performance liquid chromatography hyphenated with a quadrupole Orbitrap mass spectrometer for the quantification of simplexin embedded in different biocomposites. Satisfactory linearity (R2 > 0.99) and recovery ranges (86.8–116%) with precision (relative standard deviations) of between 0.2 and 13% (n = 3) were achieved from seven biocomposites. The established protocol was further shown to be accurate and reliable in confirming the homogeneous distribution of the simplexin in different biocomposite formulations. A limited mass transfer of simplexin (< 3.5%) from one of the biocomposites into a simulated but sterilized in vitro rumen environment after a 10-day incubation was also revealed by utilizing the method. This quantitative analysis of targeted natural product within plant material-integrated polymeric platforms has potential application when controlled release is required in the bovine rumen and other biological systems.

International audience; Abstract Non-pollen palynomorphs (NPPs) are widely used to detect human activities, in addition to the anthropogenic indicators used in palynology. This paper first tries to determine the best way to approach most probable number (MPN) counting for young scientists. It then looks at the anthropogenic indicators and the different types of human activity that can reveal the studied taxa. Among the different fungal spores, coprophilous fungi are very useful to evidence pastoral activities and grazing pressure. Numerous taxa related to dung are also indicators of decaying organic matter and deserve our attention. Erosion processes due to human activities increase the representation of fungal spores. Development of carbonicolous fungal spores in association with fire and algal assemblages due to eutrophication are also considered. Indeed, studies focusing on modern analogues have greatly improved our understanding of spore taphonomy, and the relationship between spore abundance and local livestock biomass and composition.

International audience

International audience; Peatlands are important records of past environmental changes. Based on a multiproxy analysis, the main factors influencing the evolution of a peatland can be divided into autogenic and allogenic. Among the important allogenic factors, apart from climate change, are deforestation and drainage, which are directly associated with human impact. Numerous consequences arise from these processes, the most important of which are physical and chemical denudation in the catchment and the related hydrological disturbances in the catchment and peatland. The present study determined how human activities and the past climatic variability mutually influenced the development of a small peatland ecosystem. The main goals of the study were: (1) to trace the local changes of the peatland history over the past 600 years, (2) to investigate their relationship with changes in regional hydroclimate patterns, and (3) to estimate the sensitivity of a small peatland to natural and human impact. Our reconstructions were based on a multiproxy analysis, including the analysis of pollen, macrofossils, Chironomidae, Cladocera, and testate amoebae. Our results showed that, depending on the changes in water level, the history of peatland can be divided into three phases as follows: 1/the phase of stable natural conditions, 2/phase of weak changes, and 3/phase of significant changes in the catchment. Additionally, to better understand the importance of the size of catchment and the size of the depositional basin in the evolution of the studied peatland ecosystem, we compared data from two peatlands – large and small – located close to each other. The results of our study indicated that “size matters,” and that larger peatlands are much more resilient and resistant to rapid changes occurring in the direct catchment due to human activities, whereas small peatlands are more sensitive and perfect as archives of environmental changes.

A multi-proxy record derived from sediments collected from an infilled lake basin within the area of the Serteya II site, Western Russia, was used to reconstruct the palaeoenvironment development of this site over the past ca. 9000 years. Despite there being archaeological evidence of a human presence in this area spanning several millennia, the results from pollen analysis indicate only a small-scale human impact on vegetation during the prehistory, reinforcing existing ideas that lifeways based upon hunting, fishing and gathering (h-f-g) were maintained over an extended period of time at this location. Human activities remained relatively extensive during the historical periods, although the first evidence of cereal cultivation dates to the Middle Ages. The results of earlier investigation, which suggested that cereal cultivation and animal husbandry may have begun at Serteya in the Late Neolithic, have not been confirmed by the presented dataset (or, at least, cannot be seen in it). The results from macrobotanical analysis reveal a gradual lowering of the lake-level, but with intervening transgression phases ca. 5550–3600 cal. BC and, more briefly, around the time of the 4.2 ka BP cooling event. The Late Neolithic pile dwelling settlement (dated to 2500–2200 cal. BC) that was present in the immediate area, and from which the samples are drawn, was situated in shallow water - the depth of which varied seasonally - and in the close vicinity of the shoreline. The gathering of berries and nuts, as well as starch-rich aquatic plants, seems to have played an important role in subsistence, which was further supported by hunting and fishing. Following a brief phase during which the pile dwelling settlement went into decline, the increased exploitation of aquatic plants appears to have intensified between ca. 2200 and 2000 cal. BC.

Here, we describe the full-length genome sequence of a novel potyvirus, tentatively named “miscanthus sinensis mosaic virus” (MsiMV), isolated from Miscanthus sinensis (silver grass) held in a post entry quarantine facility following its initial import into Western Australia, Australia. The MsiMV genome encompasses 9604 nucleotides (nt) encoding a 3071 amino acids (aa) polyprotein with conserved sequence motifs. The MsiMV genome is most closely related to sorghum mosaic virus (SrMV) with 74% nt and 78.5% aa sequence identity to the SrMV polyprotein region. Phylogenetic analysis based on the polyprotein grouped MsiMV with SrMV, sugarcane mosaic virus (SCMV) and maize dwarf mosaic virus (MDMV). This is the first report of a novel monopartite ssRNA virus in Miscanthus sinensis related to members of the genus Potyvirus in the family Potyviridae.

Here, we describe the full-length genome sequence of a novel potyvirus, tentatively named "Miscanthus sinensis mosaic virus" (MsiMV), isolated from Miscanthus sinensis (silver grass) held in a post-entry quarantine facility after being imported into Western Australia, Australia. The MsiMV genome is 9604 nucleotides (nt) in length, encoding a 3071-amino-acid (aa) polyprotein with conserved sequence motifs. The MsiMV genome is most closely related to that of sorghum mosaic virus (SrMV), with 74% nt and 78.5% aa sequence identity to the SrMV polyprotein region. Phylogenetic analysis based on the polyprotein grouped MsiMV with SrMV, sugarcane mosaic virus (SCMV), and maize dwarf mosaic virus (MDMV). This is the first report of a novel monopartite ssRNA virus in Miscanthus sinensis related to members of the genus Potyvirus in the family Potyviridae.

In the present paper, we describe how a robust and fundamental methodology was developed for extraction and determination of a principal natural toxin compound, simplexin, from a series of bulk biocomposites. These complex matrices were fabricated by direct encapsulating either ground plant particles or an ethanolic crude extract of the Australian toxic pasture plant Pimelea trichostachya in the biodegradable polymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Proton nuclear magnetic resonance spectroscopy was initially employed to examine the chemical compositions of these complicated systems. Then, a more sensitive strategy was developed and validated by combining solid-phase extraction and ultrahigh-performance liquid chromatography hyphenated with a quadrupole Orbitrap mass spectrometer for the quantification of simplexin embedded in different biocomposites. Satisfactory linearity (R

(IF 4.45: Q1); International audience; Few sedimentary archives of lake meromixis are available in palaeolimnological records, because long- term observations are limited in time and indisputable sediment proxies of hypolimnetic anoxia are still scarce. Here we use visible and near infrared (VNIR), and short-wave infra-red (SWIR) hyperspectral imaging combined with geochemical analyses to reconstruct lake stratification history, redox status and mixing conditions in the water column of Lake Son Kol (Kyrgyzstan) in Central Tian Shan during the last 8500 years. In particular, the detection of Bacteriopheophytin a (Bphe a), a pigment produced by anoxygenic phototrophic bacteria at the chemocline of meromictic lakes, emphasizes episodes of multi- decadal to centennial hypolimnetic anoxia in Lake Son Kol. Phases of hypolimnetic anoxia are inferred from the deposition of dark organic sediments within a stratified lake system, which occurred during periods of increased snowmelt (and solid winter precipitation) and warmer spring/summer tempera- tures that promoted floods and the export of terrestrial material from the catchment. Prolonged euxinic conditions in bottom waters (involving the development of a stable chemocline) are reported around 8500, 8400, 8200e7800, 7700e7500, 7300e7000, 6500e6100, 6000e5700 and 5500e5250 cal yr BP. At ca. 5250 cal yr BP, the chemocline abruptly vanished as Lake Son Kol tipped into a regime with pre- dominantly cooler and well-mixed conditions (predominance of oxygenic phototrophs), coeval with higher lake levels. The disappearance of hypolimnetic anoxia in Lake Son Kol coincides with strength- ened wind conditions that imply enhanced lake overturning and upward mixing of nutrients in the water column. This study reveals the strong potential of hyperspectral imaging, in combination with more classical palaeolimnological approaches, to reconstruct the lake trophic and mixing history and explore the controlling mechanisms at work on decadal to centennial timescales. Our results outline how abrupt ecosystem changes may occur even in the absence of anthropogenic climate change.

Peatlands are natural geoarchives which record within organic deposits a picture of the past environmental changes. Depending on the preserved proxy, we are able to reconstruct various aspects of palaeoenvironmental changes, e.g. using pollen (vegetation composition), plant macrofossils (local vegetation changes), testate amoebae and zoological remains (hydrological changes) or XRF scanning (geochemical changes). Here, we investigated changes in land use and climate of western Russia using a range of biotic and abiotic proxies. This part of Europe is characterized by a continental climate, which makes this region very sensitive to climate change, in particular to precipitation fluctuations. Furthermore, in the last two centuries strong human impact in that area has been noticed. The Serteya kettle hole mire (55°40'N 31°30'E) is situated in the Smolensk Oblast in Western Dvina Lakeland. Study site is located close to the range of plant communities belonging to the hemiboreal zone, making it an ideal position to trace the plant succession of Eastern Europe. Preliminary dating of the material proves that the average rate of biogenic deposits in the reservoir was approx. 1 m per 600 years. The majority of the European peatlands was in some sense transformed as a result of drainage and land use practices in their basins. Serteya kettle hole mire allowed us to accurately track how a small ecosystem responds to palaeoenvironmental changes. Preliminary results will show the major fluctuations of the mire hydrology accompanied by the changes in the land use in the region. Our goal is also to determine the resistance and resilience of peat bogs to disturbances.

Cattle grazing the pastures of inland Australia can be poisoned by ingestion of certain native Pimelea plant species, particularly Pimelea trichostachya and Pimelea simplex. The Pimelea toxin, simplexin, causes often fatal restriction of the pulmonary venules, with resultant heart impacts and characteristic fluid accumulation (oedema) of the jaw and brisket regions. In certain years heavy livestock losses can occur. Currently, there is no effective vaccine or antidote for Pimelea poisoning and the only management strategy is to reduce contact between toxic plants and susceptible stock, for beef producers to avoid potentially devastating poisoning events. Nevertheless, previous research has demonstrated that prolonged low dose feeding diminished the effect in animals. It was postulated that the animal exposed to prolonged low doses developed a mechanism for detoxifying simplexin, possibly through adaptation of the rumen microbial environment. The present study seeks to investigate the use of a biopolymer/toxin composite to foster toxin-degrading microbe populations. The objectives are to manufacture biopolymer composites based on biodegradable polylactic acid (PLA), polyhydroxyalkanoates (PHAs) and/or polycaprolactone (PCL), as toxin slow-release systems for the rumen that would have broad utility across a range of plant toxins and other beneficial rumen compounds. The poster covers the manufacturing, characterisation and performance of the biopolymers in a simulated rumen environment. Preliminary results of different biopolymers/composites containing Pimelea material and toxin extracts in an in vitro simulated rumen environment for up to 30 days are presented. It was found that the release rate could be tailored by choosing the right type of biopolymer.

Pimelea poisoning in grazing cattle, also known as St George or Marree Disease, has been a long-time pestilence for the pastoral industry throughout arid regions of inland Australia. The causative species Pimelea (Thymelaeaceae), native to Queensland, New South Wales and South Australia, have been confirmed, with the secondary metabolite simplexin, a daphnane orthoester, being extracted and identified as the principal toxin. Despite the lack of effective prevention or treatment for Pimelea poisoning, naïve calves have previously been demonstrated to develop detoxification capability following prolonged low-dose simplexin intake. A variety of composites are being fabricated by encapsulating Pimelea plant material or a crude extract in biodegradable and biocompatible polyesters, aiming to develop a sustained toxin release mechanism. Studies on screening potential rumen microflora able to decompose simplexin during rumen-fluid fermentation are being conducted simultaneously. In this project, a quantification method for simplexin within these biocomposites was developed and validated utilising solid-phase extraction combined with UHPLC-Q-Orbitrap MS/MS. Reliable simplexin measurement in matrices will allow investigations into the material composition, geometry and rumen microorganism’s effects on the controlled release kinetics of simplexin in vitro. The degradation patterns of toxin delivery systems when exposed to simulated rumen environments will also be thoroughly assessed on both microscopic and chemical scales. Mathematical models of the underlying mass transport mechanisms will ultimately be established through approaches ranging from simple empirical correlations to stochastic simulations, which hold the potential to facilitate future design, optimisation, and prediction of other intra-ruminal devices based on biodegradable polymers.

International audience; A 4 m core was extracted from the center of a peatland located in the Drugeon valley (France). Thirteen radiocarbon dates were used to build a robust age model. Testate amoebae were used for reconstructing mire surface wetness. High-resolution pollen analysis of the sequence reconstructed 9 millennia of development of the peatland and its surrounding vegetation. During the early/middle Holocene (9500 to 5800 cal BP), warm conditions led to high evapotranspiration and low water levels. The vegetation history is characterized by the development of a Pinus and a mixed Quercus forest. From 5800 cal BP, testate amoebae show wetter conditions, indicating the onset of the cooler Neoglacial period. The cooling is also evidenced by the development of Abies and Fagus trees, replacing the oak forest. The first indicators of human impact appear at about 4800 cal BP, and indicators of farming activity remains very rare until ca. 2600 cal BP, at the beginning of the Iron Age. The development of the peatland responded to climatic fluctuation until 2600 cal BP, after which human impact became the main driver. The last millennium has been characterized by sudden drying and the spread of pine on the peatland.

The service lifetime of polymer films is controlled by the chemical reactions leading to chain scission and the mediating environmental factors. For application as agricultural cropping film, controlled accelerated degradation is required. For a photo-sensitive linear low density polyethylene (LLDPE) + 1% nano-titania (as the anatase/rutile mixed phase P25), the environmental factors are not only UV dose and temperature but also soil parameters such as moisture and organic material content. This provides a challenge in predicting the useful lifetime from laboratory accelerated ageing studies. To enhance degradation when the (LLDPE + 1% P25) is buried, UV-C pre-irradiation has been shown to accelerate strength loss but the rate of embrittlement is not sufficient for the application as crop propagation film. Biodegradable poly(butylene adipate-co-terephthalate) or PBAT has a higher rate of degradation when buried outdoors in soil than when buried under laboratory conditions: The elongation at break fell from 900% to 70% in one month in the field while similar changes required 6 months in the laboratory. The small changes in M n ¯ for embrittlement in the field suggests that the loss of mechanical properties was not linked to bulk property changes but rather to surface morphology (cracks and holes) as seen by SEM. This suggests that even in thin films, enzyme-mediated hydrolysis of PBAT is surface controlled. DNA analysis of the soil around the buried films after 35 days ageing outdoors showed fungi play a more dominant role in PBAT biodegradation compared to bacteria. UV degradation of PBAT film is controlled by the photochemistry of the terephthalate moiety in the polymer and the development of fluorescence is a useful indicator of the extent of photo-degradation.

The determination of the safe working life of polymer materials is important for their successful use in engineering, medicine and consumer-goods applications. An understanding of the physical and chemical changes to the structure of widely-used polymers such as the polyolefins, when exposed to aggressive environments, has provided a framework for controlling their ultimate service lifetime by either stabilising the polymer or chemically accelerating the degradation reactions. The recent focus on biodegradable polymers as replacements for more bio-inert materials such as the polyolefins in areas as diverse as packaging and as scaffolds for tissue engineering has highlighted the need for a review of the approaches to being able to predict the lifetime of these materials. In many studies the focus has not been on the embrittlement and fracture of the material (as it would be for a polyolefin) but rather the products of degradation, their toxicity and ultimate fate when in the environment, which may be the human body. These differences are primarily due to time-scale. Different approaches to the problem have arisen in biomedicine, such as the kinetic control of drug delivery by the bio-erosion of polymers, but the similarities in mechanism provide real prospects for the prediction of the safe service lifetime of a biodegradable polymer as a structural material. Common mechanistic themes that emerge include the diffusion-controlled process of water sorption and conditions for surface versus bulk degradation, the role of hydrolysis versus oxidative degradation in controlling the rate of polymer chain scission and strength loss and the specificity of enzyme-mediated reactions.

International audience; During the Industrial Revolution and until the 19th century, the fuel used in metallurgy was charcoal. The frequent charcoal-making places identified in European archaeological sites are one of the only direct markers of this activity. Understanding the soil stratigraphy of these locations enables us to characterize the intensity of charcoal production and especially to grasp an insight into the forest management of the studied site during charcoal making. Two types of soil profiles have been observed in Europe. The first presents one or several sterile horizons identifiable with the naked eye, separating charcoal levels. The second, which is the most commonly observed type at European archaeological sites, is characterized by a single charcoal level of variable thickness. For the present study, located in eastern France (Franche-Comté), we propose to characterize the soil profile of a charcoal platform, which looks like the second type observed at the European scale, through the application of an innovative pair of methods: The Raman analysis and micromorphology. The Raman paleothermometer, defined by Deldicque et at. (2016) was adapted to define the temperatures reached in charcoal-making contexts. These measurements agree with the literature and experiments. These temperatures are regularly distributed over the profile, confirming the reuse of the platform. Similarly, the micromorphology of the soil profile reveals clear indicators of reuse, with no evidence of long interruptions in charcoal making.

International audience

La présence conjointe de nombreuses analyses paléo-environnementales et de plusieurs programmes de prospection archéologique vient renouveler notre compréhension des dynamiques anciennes d’occupation dans les montagnes du Morvan et du Jura. Ces informations peuvent également être croisées avec un important corpus d’archives médiévales et modernes jusqu’ici peu exploitées. Une mise en lien systématique de ces trois sources de données devient possible grâce à la spatialisation des informations et la définition de cadres chronologiques communs. L’étude des phases d’expansion ou de repli de l’anthropisation, notamment pour les périodes médiévales et modernes, permet d’évaluer une réelle spécificité des dynamiques d’occupation dans deux massifs de montagnes aux contraintes environnementales diverses. L’utilisation de données pluridisciplinaires met enfin en lien ces évolutions avec les mutations intervenant dans la structuration des occupations humaines et de leur encadrement politique. The results of numerous paleoenvironmental analyses and recent archeological surveys allow us to renew our understanding of settlement and land-use evolution in the Morvan and Jura Mountains (eastern France). Furthermore, these data can be completed by a large and underused collection of medieval and modern archives. A systematic cross-reading between these different types of data has been carried out, using geolocation and association with common chronological frameworks. It becomes possible to describe the phases of growth and decrease of human activities, with a particular accuracy for medieval and modern periods. We will try to evaluate in which way this evolution reveals some specific features associated with mid-mountain areas, within two regions characterized by various environmental stresses. The use of multidisciplinary data also helps to connect land-use evolutions with other changes affecting settlement patterns and political networks.

A Greenlandian (Early Holocene) palaeochannel of the Meuse River is described from Autrecourt-et-Pourron in the Ardennes region of northern France. During the Younger Dryas, fluvial deposits represent a high-energy, sinuous palaeochannel, but at the onset of the Holocene, progressive channel abandonment resulted in the establishment of a low-energy meandering river system. Well-dated studies using palynology, carpology, malacology and geomorphology reveal a Greenlandian succession of changes in fluvial dynamics and vegetation. Between 11,700 and 11,400 cal yr BP, warmer temperatures led to the development of a birch community (Betula sp.) within an open grassland, dominated by herbaceous cold-adapted plants (Linum alpinum, Plantago montana, Artemisia sp., Juniperus sp.). Between 11,400 and 11,100 cal yr BP, the river and the vegetation dynamics reflected two short-term climate events. Around 11,400 cal yr BP, the palaeochannel became separated from the active channels of the Meuse River but remained dominated by waterlogged wetlands. This cold and wet phase represents the “Preboreal Oscillation” also referred as the “11.4 ka event”. Around 11,300 cal yr BP, the records suggest that fire frequency increased close to the channel, and may indicate a dry episode that reflects a sharp, short-lived rise in temperature. Between 11,100 and 10,700 cal yr BP (Late Preboreal phase), the channel received flood deposits again. Salix and helophytes developed while Populus colonised the riverbank. From 10,700 cal yr BP, at the beginning of the Boreal phase, the palaeochannel was finally abandoned and dense temperate woodland with Corylus avellana and Quercus spp. became established. Based on its high chronological resolution, Autrecourt-et-Pourron represents a key locality in north-western Europe to investigate environmental change in connection with Early Holocene short climate variations. In addition, the results highlight the valuable contribution of carpological analyses in improving the spatial resolution of reconstructions of vegetation cover.

Polyethylene (PE) based films are commonly used in agriculture for different applications such as mulching, walk-in tunnel and mini greenhouse. In the case of mini greenhouse, the thin film creates a confined environment providing favourable conditions for crop growth, such as increased temperature and moisture retention, hence reducing the need for irrigation and agro-chemical treatments. However, in this specific application, it is necessary to control the rate of degradation of the film above ground to enable healthy crop growth. Several studies have investigated the photo- and/or thermo-oxidation of PE in sunlight and when buried in soil or compost. However the degradation rate is not well controlled and the degradation mechanisms are not fully understood. The service lifetime of polymer films is controlled by the chemical reactions leading to chain scission and mediating environmental factors. For application in agricultural cropping films, a controlled accelerated degradation is required. The rate of PE film degradation can be influenced by its intrinsic properties (such as polymer grade, concentration and/or type of pro-degradants) but also by environmental factors, such as UV dose, temperature and humidity. However, in practice, these are not the only factors controlling the polymer lifetime, with poor translation from model (laboratory based) accelerated ageing studies to in-field application. This creates a challenge in accurately predicting the useful lifetime of a given film. Due to the confined environment created by the thin films, the ultimate service lifetime of the film may be affected by unexpected environmental factors such as the composition and photo-chemistry of soil components. The evaluation of the impact of these environmental factors, including the effect of soil type on the above-ground degradation of PE, has not previously been addressed. This project aims to better understand the effect of such factors on the PE photo-degradation processes, by correlating the film lifetime to key soil parameters such as soil type, chemistry and properties. The above-ground degradation of oxo-degradable PE thin films as well as a control film, were investigated over a variety of soils, and over isolated organic substances such as humic and fulvic acids.Outdoor weathering field trials performed using oxo-degradable PE thin films were conducted across several sites around Australia. It was found that a site factor, that was apparently independent of total solar dose and temperature, significantly impacted the rate and extent of photo-oxidation. This finding was confirmed by controlled laboratory-based accelerated ageing trials of both PE film with no pro-degradant as well as with oxo-degradable PE films, which revealed that the rate and extent of PE photo-oxidation did not correlate with temperature under the film nor UV exposure, but was soil dependent. Under accelerated photo-oxidative conditions, the time to reach embrittlement for a PE film aged over the soil with a high content of organic matter (OM 8.4%) was halved (at 24.5 days) when compared to similar film aged over air (at 48 days). Further investigation revealed that humic acids and fulvic acids within soil organic matter may contribute to the change in the oxidation rate of PE photo-oxidation, possibly through the formation of volatile reactive oxygen species that may form under photo-oxidative conditions. In addition, the presence of water also had a significant impact on the rate of photo-oxidation.Overall, additional environmental factors to solar dose and temperature were influencing the rate of PE photo-degradation. The key factors were found to be the presence of condensed water and soil type. For the latter factor, the specific soil properties of importance with respect to film degradation appeared to be associated with organic matter, although the impact of soil on PE photo-oxidation was found to be complex and likely dependent at least in part on soil components that varied between different soil types, consequently influencing their photo-chemistry. This knowledge could assist in designing a modelling tool to recommend the appropriated time-controlled PE film suitable for a specific crop cycles at specific sites across Australia. These findings could also be transferred to other degradable PE film applications, such as mulch films, plastic bags and other packaging products.

International audience

Im Rahmen einer Präventivgrabung wurde auf dem Gebiet der Gemeinde Magny-Cours (Departement Nièvre) ein großes antikes Heiligtum freigelegt. Die Bedeutung des Fundplatzes beruht eher auf der Entdeckung mehrerer Torfzonen mit organischen Funden (Exvotos und Holzabfälle) als auf dem Heiligtum selbst. Ein interdisziplinärer Ansatz ermöglichte es, die Natur dieser Funde und ihre Verbindung mit den benachbarten Kultstrukturen zu verstehen. Die archäologische Studie wurde durch geomorphologische und paläoumweltliche Studien ergänzt, insbesondere dendrologische, karpologische, palynologische und sedimentäre Analysen., A large ancient sanctuary was discovered during preventive excavations at Magny-Cours (Nièvre). More than the cultural complex itself, the main interest of the site was the discovery of several peat bogs in which organic items (ex-voto, scraps of wood) were preserved. A multidisciplinary approach was used to understand the nature of these remains and their relation with the neighboring cultual structures. In this way, the archaeological study was completed by a series of geomorphological and palaeoenvironmental analyses, more specifically in the fields of dendrology, carpology, palynology, and the geology of sediments., Dans le cadre d’une opération d’archéologie préventive, un important sanctuaire antique a été mis au jour sur la commune de Magny-Cours (Nièvre). Bien plus que l’ensemble cultuel lui-même, c’est la découverte de plusieurs zones de tourbes ayant conservé des matériaux organiques (ex-voto et déchets de bois) qui constitue l’intérêt du site. Une approche multidisciplinaire y a été appliquée pour comprendre la nature de ces vestiges et leur lien avec les structures cultuelles voisines. Ainsi, l’étude archéologique a été complétée par des analyses géomorphologiques et paléoenvironnementales en particulier dendrologiques, carpologiques, palynologiques et sédimentaires.

The Franche-Comte region played an important role in the iron industry since at least the Hallstatt Period, but particularly since the industrial revolution (from the end of the 18th century). The presence of thousands of charcoal kilns in the main forest of Besancon (regional capital) is the subject of this study. The aim was to further our understanding of these archaeological objects, and to characterize the impact of charcoal production on the past vegetation. A geophysical survey (magnetic susceptibility) was conducted on two platforms. Charcoal analyses of 11 charcoal kilns and a regressive approach on the current vegetation were undertaken for comparative purposes. The platforms are modern and seem to have been used several times during a short 250-year period. Based on historical sources and compared with forests used for the iron industry, the vegetation of the forest of Chailluz appears to have been harvested for a variety of purposes, notably the iron industry and domestic use. Tree species used to produce charcoal were correlated with the environmental offering and site conditions but charcoal production seemed to open the forest structure. More light demanding taxa and fewer shade-tolerant species than nowadays have been observed.

The impact of commonly used agrichemicals (Paraquat, Mancozeb, Chlorpyrifos and Sulfur) on the environmental stability of polyethylene films has been evaluated under accelerated photo-oxidative conditions. Paraquat and Mancozeb when applied to unstabilized clear polyethylene film, followed by exposure to UV radiation, resulted in direct attack of the polymer, evident by faster rates of oxidation and shorter times to embrittlement compared to a polyethylene control. Reapplication of these chemicals during exposure, as often occurs in agricultural practice, resulted in even faster degradation. In contrast, Sulfur and Chlorpyrifos did not have a significant effect on the photodegradation of exposed unstabilized polyethylene film. When the polyethylene film was pigmented (white top layer containing rutile titanium dioxide and carbon black in the bottom layer) and stabilized with the addition of hindered amine stabilizers (HAS), differences in oxidation susceptibility were seen with repeated exposure to Paraquat showing the most dramatic effect. This was evident by an increased carbonyl index, decrease in elongation at break and an increase in tensile stress at yield compared to a control film and other agrichemical treatments. These studies enable degradation from accelerated consumption of stabilizers by the agrichemicals (and their degradation products) to be differentiated from enhanced photochemical initiation of the polyethylene degradation.

Paleoenvironmental studies previously performed on Lake Igaliku revealed two agropastoral phases in south Greenland: the Norse settlement from AD 986 to ca. AD 1450 and the recent installation of sheep farmers, since the 1920s. To improve the knowledge of the timing and magnitude of the Greenlandic agropastoral activities, a lipid inventory was realized and compared with biological and geochemical data. During the 12th century, a major increase in deoxycholic acid (DOC) and coprophilous fungal spores revealed a maximum of herbivores. Synchronously, a minimum of the n-C29/ n-C31 alkane ratio and tree and shrub pollen and a maximum of triterpenyl acetates showed a reduction in the tree and shrub cover, because of grazing activities. Lupanone, produced by angiosperms, appeared simultaneously in the molecular content, probably revealing an introduction of plant species by the Norse, as it has been the case for Rumex spp. No major erosion was recorded by trimethyl-tetrahydrocrysenes (TTHCs) and titanium (Ti) fluxes. No massive algal production, identified by the n-C17/total n-alkane ratio and mesotrophic diatoms, was either revealed. After the Norse abandon (around AD 1450), a return of the vegetation to quasi-pristine conditions was observed in the molecular content. Finally, a re-introduction of sheep in the 1920s provoked major impacts between the 1970s and the 1990s. A major decrease in the n-C29/ n-C31 alkane ratio and tree and shrub pollen associated with maxima of triterpenyl acetates, TTHCs, Ti fluxes, and mesotrophic diatoms highlighted a reduction in the tree and shrub cover, a strong soil mobilization, and algal blooms, probably linking to the recent mechanized creation of hay fields and the massive use of fertilizers. In this study, molecular biomarkers revealed two periods of major impacts: the 12th century and between the 1970s and the 1990s, separated by centuries without agropastoral practices, allowing a quasi-resilience of the vegetation.

La campagne 2016 du programme de recherche sur les sites ecclésiaux et monastiques de l’archipel du Kvarner a essentiellement porté sur la fouille du petit complexe antique et médiéval septentrional du site de Mirine-Fulfinum – secteur dit de « l’église à trois absides » – (île de Krk), du 11 au 23 avril 2016, et sur la poursuite de la fouille de la grande église paléochrétienne du complexe de Martinšćica (île de Cres) du 27 juin au 14 juillet (fig. 1). Fig. 1 – Carte de l’archipel du Kvarner...

The Kochersberg loess area, west of Strasbourg (France), has been explored in order to reconstruct the Holocene landscape dynamics. Sediments, pollen and plant macro-remains were analysed from an organic rich sediment core, sampled in the thalweg of a small catchment. The several proxies are offering a multiscalar view of landscape evolution from the Neolithic to the Middle Age. At the catchment scale, major changes in the landscape are always associated with intense phases of occupation revealed by archaeological excavations.

The changes to the polymer microstructure during thermo- and photo-oxidative aging of LLDPE-based films have been investigated by thermal fractionation. During thermo-oxidative aging there was an exponential increase in the rate of the reduction in the fraction of polymer segments with a methylene sequence length (MSL) of approximately 249. All films embrittled only after the fraction of these segments decreased to below 7.5%, suggesting that the thermal fractionation data can be correlated to embrittlement time. In contrast, during photo-oxidative aging there was an initial rapid reduction followed by a gradual increase in the relative fraction of segments with an average MSL of 249. The initial decrease in the fraction of segments with an average MSL of 249 was similar to what was observed during thermo-oxidative aging and was consequently attributed to chain scission and/or oxidation of chains including tie-molecules. The latter increase in the fraction of chains with this average MSL was attributed to alkyl radical recombination which would result in an overall loss of branches and the formation of chain segments with high MSLs.

International audience; Depuis 2006, une équipe constituée de paléoenvironnementalistes du laboratoire Chrono-environnement de Besançon travaille sur les séquences lacustres du sud du Groenland. Le secteur étudié est au cœur de la zone occupée par les viking (l’Eastern settlement) entre 986 et 1450 cal. AD. Le but premier de cette étude était de mettre en évidence l’impact de cette colonisation sur un environnement vierge. L’étude des paramètres biotiques (grains de pollen, microfossiles non polliniques et diatomées) et abiotiques (sédimentologie, géochimie et isotopes) a été étendue à l’ensemble de certaines séquences afin de replacer la partie viking dans son contexte holocène. Cinq missions de terrain ont permis de collecter une vingtaine de séquences lacustres. La séquence sédimentaire prélevée dans le lac d’Igaliku (N61°00’22”, W45°26’28), à côté du site médiéval de Garðar débute aux environs de 8000 cal. BC et l’enregistrement pollinique commence à partir de 6100 cal. AD ; elle fait partie des rares séquences complètes et bien datées (28 dates radiocarbone) de ce secteur subarctique. La première moitié de l’Holocène, jusque vers 2500 cal. BC, est marquée par un couvert végétal dominé par le genévrier et le saule. Ensuite l’apparition des conditions plus humides du Néoglacial favorise l’essor du bouleau glanduleux, puis du bouleau pubescent. Dès la fin du premier millénaire après Jésus-Christ, la colonisation viking est marquée par une pression pastorale qui se traduit par l’augmentation brutale des taux de spores de champignons coprophiles, la diminution des pourcentages de bouleau et l’apparition de plantes importées comme l’oseille, le bouton d’or ou le pissenlit. Le développement de ces activités agropastorales entraine une érosion modérée des sols mais les diatomées montrent que le système lacustre n’est en rien affecté par ces changements. Dès 1300 cal. AD la pression pastorale et l’érosion diminuent, données corroborées par l’archéologie. À l’orée du Petit Âge Glaciaire, les viking se tournent vers une alimentation tirée de la mer aux dépends de l’élevage. Aux environs de 1450 cal. AD, le peuplement disparait mais la résilience est modérée du point de vue de la végétation car les plantes importées se maintiennent. La réintroduction de l’élevage au début du XXe siècle est parfaitement marquée par les différents paramètres d’étude : si l’impact sur la végétation n’est guère différent de ce qui a été observé pendant la période viking, l’érosion est largement supérieure et l’emploi d’engrais bouleverse définitivement l’écosystème lacustre.

International audience; Assessing the extent to which changes in lacustrine biodiversity are affected by anthropogenic or climatic forces requires extensive palaeolimnological data. We used high-throughput sequencing to generate time-series data encompassing over 2200 years of microbial eukaryotes (protists and Fungi) diversity changes from the sedimentary DNA record of two lakes (Lake Bourget in French Alps and Lake Igaliku in Greenland). From 176 samples, we sequenced a large diversity of microbial eukaryotes, with a total 16 386 operational taxonomic units distributed within 50 phylogenetic groups. Thus, microbial groups, such as Chlorophyta, Dinophyceae, Haptophyceae and Ciliophora, that were not previously considered in lacustrine sediment record analyses appeared to be potential biological markers of trophic status changes. Our data suggest that shifts in relative abundance of extant species, including shifts between rare and abundant taxa, drive ecosystem responses to local and global environmental changes. Community structure shift events were concomitant with major climate variations (more particularly in Lake Igaliku). However, this study shows that the impacts of climatic fluctuations may be overpassed by the high-magnitude eutrophication impacts, as observed in the eutrophicated Lake Bourget. Overall, our data show that DNA preserved in sediment constitutes a precious archive of information on past biodiversity changes.

International audience; Freshwater lakes play a key role in the global carbon cycle as sinks (organic carbon sequestration) and sources (greenhouse gas emissions). Understanding the carbon cycle response to environmental changes is becoming a crucial challenge in the context of global warming and the preponderance of human pressures. We reconstructed the long-term (1500 years) evolution of trophic functioning of the benthic food web, based on methanotrophic ancient DNA and chironomid isotope analyses). In addition, human land use is also reconstructed in three different lakes (eastern France, Jura Mountains). Our findings confirm that the benthic food web can be highly dependent on methane-derived carbon (up to 50% of the chironomid biomass) and reveal that the activation of this process can correspond to a natural functioning or be a consequence of anthropic perturbation. The studied lakes also showed a similar temporal evolution over the last century with the disappearance of the profundal aquatic insects (Chironomidae, Diptera), considered as keystone for the whole lake food web (e.g., coupling benthic-pelagic), inducing a potential collapse in the transfer of methane to top consumers. This functional state, also called the dead zone expansion, was caused by the change in human land-use occurring at the beginning of the 20th century. The strong modification of agro-pastoral practices (e.g., fertilization practices, intensive grazing, and sewage effluent) modified the influx of nutrients (by diffuse and/or point-source inputs) and induced a significant increase in the trophic status and organic matter sedimentation to reach unprecedented values. Further studies should be planned to assess dead zone expansion and, according to the regime shift theory, to provide environmental tipping points for sustainable resource management.

La campagne 2016 du programme de recherche sur les sites ecclesiaux et monastiques de l’archipel du Kvarner a essentiellement porte sur la fouille du petit complexe antique et medieval septentrional du site de Mirine-Fulfinum – secteur dit de « l’eglise a trois absides » – (ile de Krk), du 11 au 23 avril 2016, et sur la poursuite de la fouille de la grande eglise paleochretienne du complexe de Martinscica (ile de Cres) du 27 juin au 14 juillet (fig. 1). Fig. 1 – Carte de l’archipel du Kvarner...

Climate archives available from deep sea and marine shelf sediments, glaciers, lakes, and ice cores in and around Greenland allow us to place the current trends in regional climate, ice sheet dynamics, and land surface changes in a broader perspective. We show that, during the last decade (2000s), atmospheric and sea surface temperatures are reaching levels last encountered millennia ago, when northern high latitude summer insolation was higher due to a different orbital configuration. Records from lake sediments in southern Greenland document major environmental and climatic conditions during the last 10,000 years, highlighting the role of soil dynamics in past vegetation changes, and stressing the growing anthropogenic impacts on soil erosion during the recent decades. Furthermore, past and present changes in atmospheric and oceanic heat advection appear to strongly influence both regional climate and ice sheet dynamics. Projections from climate models are investigated to quantify the magnitude and rates of future changes in Greenland temperature, which may be faster than past abrupt events occurring under interglacial conditions. Within one century, in response to increasing greenhouse gas emissions, Greenland may reach temperatures last time encountered during the last interglacial period, approximately 125,000 years ago. We review and discuss whether analogies between the last interglacial and future changes are reasonable, because of the different seasonal impacts of orbital and greenhouse gas forcings. Over several decades to centuries, future Greenland melt may act as a negative feedback, limiting regional warming albeit with global sea level and climatic impacts. 2012 John Wiley & Sons, Ltd. How to cite this article

La palynologie a ete liee a l’archeologie des ses debuts en France. Les recherches limitees d’abord a la Prehistoire se sont aujourd’hui systematisees sur toutes les periodes. On sait a present, quand on contemple nos paysages actuels, qu’ils sont le resultat de profonds remaniements qui ont commence il y a pres de sept millenaires, dans le but de creer et amenager les espaces agropastoraux si caracteristiques des campagnes actuelles. © Romain Etienne/ITEM Emilie Gauthier L’attention des pa...

The oxidation of linear low density polyethylene (LLDPE) films containing the combination of pro-oxidants titanium (IV) dioxide (TiO2) with either cobalt (II) stearate (CoSt) or iron (II) stearate (FeSt) have been evaluated under accelerated photo- and thermo-oxidative conditions as well as on outdoor weathering. LLDPE containing only surface-compatibilised nano-TiO2 rapidly photo-whitens and embrittles at a low apparent extent of oxidation (as measured by carbonyl index) due to formation of microscopic voids of similar to 150 nm. When CoSt was also included in the film, antagonism occurred shown by embrittlement times longer by similar to 90%, higher carbonyl index and absence of film whitening. In contrast, films containing TiO2/FeSt whitened during photo-oxidation and exhibited lower antagonism with only 44% longer times to embrittlement and lower carbonyl index. Antagonism between pro-oxidants was not observed under dark thermo-oxidative conditions. X-ray Fluorescence Microspectroscopy elemental maps revealed that the TiO2 nanoparticles were spatially correlated with iron and cobalt metal ions allowing scavenging of electrons and holes through cycling of the redox states of the metal without producing radical species to initiate polymer oxidation. It is suggested that the antagonism differences between TiO2/CoSt and TiO2/FeSt pro-oxidants is related to the respective reduction potentials of Co3+/2+ and Fe3+/2+ and their effect on the UV conduction and valence band edges of the TiO2 particle. In these ways the photochemistry of TiO2 is suppressed and the photo-oxidative lifetime is governed by the chemistry of the transition metal pro-oxidant. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.

The lake sediment record was used to reconstruct past vegetation dynamics and human impacts from the middle Neolithic (6500 cal. b.p.) to the Middle Ages (1500 cal. b.p.) around Lac d’Antre in the southern Jura mountains of France. This lake was surrounded by the Gallo-Roman sanctuary of Villards d’Heria, which has been widely investigated by archaeologists and enables a comparison between palaeoenvironmental proxies and archaeological data. Pollen and microscopic charcoal analyses were conducted on a 500 cm sediment core with eleven radiocarbon dates providing the chronological control. In a mixed oak woodland context, the successive development of Taxus, Fagus and Abies were mainly caused by climatic variations during the Neolithic, in which there was weak human impact. The first significant signs of human activity were detected during the Bronze Age from 3900 cal. b.p., followed by an increase of human pressure and woodland clearances during the Iron Age, from 2700 cal. b.p. The occupation of the Gallo-Roman sanctuary was continuous with the Iron Age occupation. All the analysed palaeoenvironmental data indicate that the strongest human impact occurred during the Gallo-Roman period, which matches the occupation of Villards d’Heria previously dated by archaeologists from 2000 to 1700 cal. b.p., 1st to 3rd century a.d. Moreover, there appears to have been a new period of human settlement close to the lake at the beginning of the Middle Ages. The low charcoal accumulation rate (CHAR) recorded during the Bronze and Iron Ages suggests that fire was not the main agent used to clear the dense woods to create new cultivated fields and pastures. High CHAR values recorded during the Roman period may represent fire use for domestic and agro-pastoral activities.

International audience; The environmental impact of the Norse landnám in Greenland has been studied extensively. But to date, no study has quantified the soil erosion that Norse agricultural practices are believed to have caused. To resolve this problem, a high resolution sedimentary record from Lake Igaliku in South Greenland is used to quantitatively reconstruct 2500 years of soil erosion driven by climate and historical land use. An accurate chronology allows for the estimation of detritic fluxes and their uncertainties. Land clearance and the introduction of grazing livestock by the Norse around 1010 AD caused an acceleration of soil erosion up to 8 mm/century in 1180 AD which is two-fold higher than the natural pre-landnám background. From 1335 AD to the end of the Norse Eastern Settlement (in the mid-fifteenth century), the vegetation began to recover from initial disturbance and soil erosion decreased. After an initial phase of modern sheep breeding similar to the medieval one, the mechanization of agriculture in the 1980s caused an unprecedented soil erosion rate of up to 21 mm /century, five times the pre anthropogenic levels. Independently, a suite of biological and geochemical proxies (including Ti and diatom concentrations, C:N ratio, 13C and 15N of organic matter) confirm that the medieval and modern anthropogenic erosion far exceeds any natural erosion over the last 2500 years. Our findings question the veracity of the catastrophic scenario of overgrazing and land degradation considered to have been the major factor responsible for Norse settlement demise. They also shed light on the sustainability of modern practices and their consequences for the future of agriculture in Greenland.

The bulk of the red blood cell membrane proteins are partitioned between two multiprotein complexes, one associated with ankyrin R and the other with protein 4.1R. Here we examine the effect of phosphorylation of 4.1R on its interactions with its partners in the membrane. We show that activation of protein kinase C in the intact cell leads to phosphorylation of 4.1R at two sites, serine 312 and serine 331. This renders the 4.1R-associated transmembrane proteins GPC, Duffy, XK, and Kell readily extractable by nonionic detergent with no effect on the retention of band 3 and Rh, both of which also interact with 4.1R. In solution, phosphorlyation at either serine suppresses the capacity of 4.1R to bind to the cytoplasmic domains of GPC, Duffy, and XK. Phosphorylation also exerts an effect on the stability in situ of the ternary spectrin-actin-4.1R complex, which characterizes the junctions of the membrane skeletal network, as measured by the enhanced competitive entry of a β-spectrin peptide possessing both actin- and 4.1R-binding sites. Thus, phosphorylation weakens the affinity of 4.1R for β-spectrin. The two 4.1R phosphorylation sites lie in a domain flanked in the sequence by the spectrin- and actin-binding domain and a domain containing the binding sites for transmembrane proteins. It thus appears that phosphorylation of a regulatory domain in 4.1R results in structural changes transmitted to the functional interaction centers of the protein. We consider possible implications of our findings for the altered membrane function of normal reticulocytes and sickle red cells.

Lu/BCAM, the unique erythroid receptor for laminin 511/521, interacts with the erythrocyte membrane skeleton through spectrin binding. It has been reported that Hereditary Spherocytosis red blood cells (HS RBC) exhibit increased adhesion to laminin. We investigated the role of Lu/BCAM-spectrin interaction in the RBC adhesion properties of 2 splenectomised HS patients characterized by 40% spectrin deficiency. Under physiological flow conditions, HS RBC exhibited an exaggerated adhesion to laminin that was completely abolished by soluble Lu/BCAM. Triton extraction experiments revealed that a greater fraction of Lu/BCAM was unlinked to the membrane skeleton of HS RBC, as compared to normal RBC. Disruption of the spectrin interaction site in Lu/BCAM expressed in the transfected K562 cell line resulted in a weakened interaction to the skeleton and an enhanced interaction to laminin. These results demonstrated that the adhesion of HS RBC to laminin was mediated by Lu/BCAM and that its interaction with the spectrin-based skeleton negatively regulated cell adhesion to laminin. Finally, the results of this study strongly suggest that the reinforced adhesiveness of spectrin-deficient HS RBC to laminin is partly brought about by an impaired interaction between Lu/BCAM and the membrane skeleton.