Next-generation ensemble projections reveal higher climate risks for marine ecosystems

Projections of climate change impacts on marine ecosystems have revealed long-term declines in global marine animal biomass and unevenly distributed impacts on fisheries. Here we apply an enhanced suite of global marine ecosystem models from the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish-MIP), forced by new-generation Earth system model outputs from Phase 6 of the Coupled Model Intercomparison Project (CMIP6), to provide insights into how projected climate change will affect future ocean ecosystems. Compared with the previous generation CMIP5-forced Fish-MIP ensemble, the new ensemble ecosystem simulations show a greater decline in mean global ocean animal biomass under both strong-mitigation and high-emissions scenarios due to elevated warming, despite greater uncertainty in net primary production in the high-emissions scenario. Regional shifts in the direction of biomass changes highlight the continued and urgent need to reduce uncertainty in the projected responses of marine ecosystems to climate change to help support adaptation planning

Reconnaissance Basement Geology and Tectonics of South Zealandia

We report new U‐Pb zircon ages, geochemical and isotopic data for Mesozoic igneous rocks, and new seismic interpretations of mostly submerged South Zealandia (1.5 Mkm2). We use these data, along with existing geological and geophysical data sets, to refine the extent and nature of geological units. Our new 1:25 M geological map of South Zealandia provides a regional framework to investigate the rifting and breakup that formed Zealandia, Earth's most submerged continent. Samples of prerift (pre‐100 Ma) plutonic rocks can be matched with on‐land New Zealand igneous suites and indicate an east‐west strike for the subduction‐related 260 to 105‐Ma Median Batholith across the Campbell Plateau. The plutonic chronology of formerly contiguous plutonic rocks in West Antarctica reveals similar pulses and lulls to the Median Batholith. Contrary to previous interpretations, the Median Batholith does not coincide with the 1,600‐km‐long Campbell Magnetic Anomaly System. Instead we interpret the continental magnetic anomalies to represent a mainly mafic igneous unit, whose shape and extent is controlled by synrift structures related to Gondwana breakup. Correlatives of some of these unsampled igneous rocks may be exposed as circa 85 Ma alkalic volcanic rocks on the Chatham Islands. Extension directions varied by up to 65° from 100 to 80 Ma, and we suggest this allowed this large area to thin considerably before final rupture to form new oceanic crust. Synrift (90–80 Ma) structures cut the oroclinal bend in southern South Island and support a pre‐early Late Cretaceous age of orocline formation.The work was supported by Core Research Funding to GNS Science by the New Zealand Government Ministry of Business, Employment and Innovation

Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change

While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends

Tectonics, sedimentation and magmatism of the Canterbury Basin, New Zealand.

This PhD investigates the tectonics, sedimentation and magmatism of the Canterbury Basin. Unlike the emergent part of Zealandia continent, the offshore Canterbury Basin has not been deformed by Cenozoic plate boundary movements and represents a rare opportunity to conduct detailed analysis of the mid- Cretaceous rifting (~110 Ma to ~85 Ma) and the Late Cretaceous to Paleogene drift sequences. The results help improve understanding of the regional processes that led to the breakup of eastern Gondwana and the far-field effects of Cenozoic plate boundary deformation. The Canterbury Basin initiated in the mid-Cretaceous (~110 Ma) as a rift system. Syn- rift sedimentation was characterised by under-filled depocenters, where early syn-rift sedimentation was dominated by short drainage systems sourced from within the basin to produce alluvial fans along fault scarps inter-fingered with axial braided river or lake deposits. The predominance of local drainage systems coupled with a low supply of sediment into the Canterbury Basin during the Late Cretaceous may partly account for the under-filling of rift depocenters. Post rift latest Cretaceous and Paleogene, pelagic sediments draped and buried most of the earlier-formed horsts, with complete burial being achieved ~60 Myr after the onset of faulting. Despite filling of the rift structures, many of the geomorphological features of the contemporary Canterbury Basin were also present in the Late Cretaceous including, the Chatham Rise and the topographic hinterland west of the basin. The timing of the Cretaceous- Paleogene marine transgression and the degree of preservation of rift structures in the Canterbury Basin, differs from that in northern Zealandia (e.g., Taranaki Basin). These differences may reflect the relative tectonic quiescence in the offshore Canterbury Basin post ~85 Ma and the ongoing influence of subduction beneath northern Zealandia in the Late Cretaceous and Eocene. A total of 346 faults were analysed, with maximum displacements ranging from <0.1 to 2.8 seconds two way time. Results of the structural interpretation of the rifting show that the Canterbury Basin was stretched in three directions forming three sets of synchronous normal faults. The parallelism the three sets of rift faults and future spreading centres suggests that the multi-directional extension in the Canterbury Basin records the early stages of Gondwana breakup. The plate tectonic forces responsible for Gondwana breakup probably commenced soon after the cessation of subduction (e.g., < 5 Myr), and ~20 Myr before breakup. With the onset of breakup extension was focused along the spreading centres and multi-directional stretching of Zealandia ceased or continued at much diminished rates. The geometries of rift fill in seismic reflection lines has been quantified using the ratio of syn-rift strata thickness to syn-rift fault throw (here referred to as the Sediment Fill Ratio - SFR). Measurements from seven sedimentary basins globally (including the Canterbury Basin), permits recognition of four types of rift basins: (1) starved (SFR≤0.2), (2) under-filled (0.21.1). The degree of syn-rift basin fill at the cessation of faulting varies with fault size across the same basin and between different rift basins for the same fault size. Small faults are more often characterized by balanced or over-filled geometries because they have low displacement rates and are located in the hangingwall of larger faults (e.g., >1 seconds TwT throw) where sedimentation rates are locally high. Rift systems dominated by large faults, such as the Canterbury Basin, tend to be under-filled, and require sediment supply from outside the rift system to become over-filled. The offshore Canterbury Basin provides a new perspective on Early Oligocene erosion that occurred between 29 and 32 Ma throughout the basin. Seismic reflection data permits mapping of erosive channels that incised the shelf and slope of the Canterbury Basin during the Early Oligocene. Similar channels are inferred onshore and offer an explanation for thickness variations of Oligocene limestones at a time when the rates of deformation were inferred to be low. Channelisation initiated due to a sea-level fall associated with uplift west of the Canterbury Basin that potentially reflects the onset of Cenozoic plate boundary deformation. The drainage system set-up during the Early Oligocene displays similar trends to the present day hydrographic pattern, which suggests that the first-order topographic elements of the eastern South Island may be 30 Myr in age or older. Seismic reflection data in the offshore Canterbury Basin has enabled us to identify 185 buried magmatic structures, some of which were previously unknown, ranging in age from mid-Cretaceous to Pleistocene. Buried volcanic edifices of 10 km within the post-breakup Late Cretaceous succession. 3. Monogenetic to polygenetic volcanoes of Paleocene to Middle Miocene age. 4. Large Miocene composite volcanoes of >10 km diameter formed in association with present-day Banks and Otago peninsulas. 5. Eruptive centers along the Chatham Rise that erupted during the Late Neogene. The continuous volcanic activity of the Canterbury Basin from the Late Cretaceous rifting to the Late Neogene was accompanied by widespread sill intrusion but did not resolve batholiths or plutons which, if present, are at depths of >10 km depth. This study increases the total known surface area of volcanoes in the Canterbury Basin by 300%, and suggests that across Zealandia, more volcanoes can be expected to exist of varying ages

Les maisons de tradition méditerranéenne de Bibracte : techniques et matériaux, types architecturaux, organisation spatiale et fonctions

International audienc

Le contrôle biologique par conservation peut-il limiter l'incidence d'une maladie virale, la JNO, transmise par les pucerons aux céréales cultivées ?

Alternatives aux néonicotinoïdes Rendu des projets réunissant des contributions des projets scientifiques d'Ecophyto et du Plan National de Recherche et Innovation-betterave avec, selon les projets, les soutiens financiers de l'Office français de la biodiversité (OFB), l’Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE) et de l'Institut technique de la betterave (ITB).National audienceCereal aphids transmit several viruses causing the Barley Yellow Dwarf (BYD) disease in autumn and/or in winter. Global warming increases the abundance, diversity and persistence of aphids at this time of the year, which is likely to be exacerbated by the ban on neonicotinoids. We therefore fear an increase indamage due to BYD viruses, and alternative methods to chemical control need to be developed. The PLANTSERV project tested at local and landscape scale whether winter flowering strips could limit the abundance of aphids in cereal fields, reduce the incidence of BYD viruses and the associated symptoms and yield losses. Winter flowering strips effectively reduce aphid abundance per plant by 26%, but not necessarily via predators, even though they are more abundant near the flowering strips (+25%). This reduction in the density of BYD vectors led to a slight reduction (2%) in virus incidence in cereals, but not to a reduction of symptoms or yield losses. Disease severity and yield losses were limited in our stud region despite the high incidence of viruses, probably due to the dominance of a BYD virus that causes less severe symptoms. This project made it possible (1) to develop an effective method for detecting viruses in cereals and aphids (2) to identify a recombinant virus (3) to show that flowering mixtures sown in winter intercropping cover crops are easily accepted by farmers, limit aphid and virus incidence and (4) that a certain level of symptoms can be tolerated while maintaining high yields. It is now necessary to test flower strips in combination with other methods to limit BYD damage and to adapt them to other climates and crops.Les pucerons des céréales transmettent les virus de la Jaunisse Nanisante de l’Orge (JNO) à l’automne-hiver. Le réchauffement climatique augmente l’abondance des pucerons, la durée de leur présence et le nombre d’espèces de pucerons à cette période, ce qui risque d’être aggravé par l’interdiction desnéonicotinoïdes. On peut donc craindre une augmentation des dégâts liés à la JNO et il faut développer des méthodes alternatives à la lutte chimique. Le projet PLANTSERV a testé si les bandes fleuries en hiver aux échelles locales et paysagères pouvaient limiter l’abondance des pucerons dans les parcellesde céréales, réduire l’incidence en virus de la JNO et les dégâts et pertes de rendement associés. Les bandes fleuries hivernales réduisent effectivement de 26% les abondances de pucerons par plant mais pas nécessairement via les prédateurs pourtant plus abondants à proximité des bandes (+25%). Cetteréduction des densités de vecteurs de la JNO entraîne une légère diminution (2%) de l'incidence des virus dans les céréales mais pas des dégâts ni des pertes de rendement. Ces dégâts et pertes sont cependant limités dans notre région d’étude malgré une incidence virale élevée, probablement en raisonde la dominance d’un virus de la JNO causant des symptômes moins sévères. Ce projet a permis (1) de mettre au point une méthode efficace de détection des virus dans les céréales et les pucerons, (2) d’identifier un virus recombinant, (3) de montrer que les mélanges fleuris semés dans les couvertsd’interculture hivernaux sont facilement acceptés par les agriculteurs, limitent les pucerons et l’incidence virale et (4) qu’un certain niveau de symptômes peut être toléré en maintenant des rendements élevés. Il est maintenant nécessaire de tester les bandes fleuries en combinaison avec d’autres leviers pour limiter les dégâts de la JNO et de les adapter à différents climats et à d’autres culture

Chronologie et répartition spatiale des établissements fortifiés tardo-laténiens du Plateau et du Jura suisses

International audienceDer vorliegende Gemeinschaftsartikel diskutiert die spätlatènezeitliche Siedlungslandschaft im heutigen Schweizer Mittelland und Jura. Trotzteilweise lückenhaftem Forschungsstand können im Untersuchungsgebiet zwanzig befestigte Siedlungen lokalisiert und, dank einer aufReferenzfundkomplexen basierenden Regionalchronologie, datiert werden. Die Zeitstellung und Belegungsdauer der Siedlungen geben Einblickein die vorherrschende Siedlungsdynamik. Während sich im Umland Genfs und im Jura eine stabile Siedlungslandschaft abzeichnet, zeigt sich imMittelland am Übergang der Stufen LT D1b zu LT D2a bei der Art der befestigten Siedlungen ein grösserer Wechsel: Praktisch alle grossen befestigtenSiedlungen werden verlassen und es entstehen kleinere Neugründungen. Der Prozess setzt sich in der Stufe LT D2b fort mit der Entstehungneuer, stärker militärisch geprägter Siedlungen.Despite the sometimes incomplete nature of the archaeological record for the late Iron Age, it is still possible to date the twenty known fortifiedsites in the Swiss Plateau and Jura. The chronology is established from a corpus of settlements in these regions, which have been recentlyenriched with new find assemblages. Thanks to the site chronology, trajectories in their occupation can be identified. While a certain continuitycharacterizes the sites of Geneva and in the Jura, a rupture appears clearly in the sites in the Swiss Plateau at the time of transition from La TèneD1b and D2a, when almost all of the large fortified sites of the Plateau were abandoned in favour of smaller foundations. From La Tène D2bonwards, these were then complemented by new sites with an essentially military character (traduction Andrew Lawrence)

Programme de recherche sur le mont Beuvray, rapport annuel 2012, référentiel

Les données consignées dans ce référentiel font l'objet d'une sytnhèse dans le rapport annuel 2012 du programme de recherche sur le Mont Beuvray sous la direction scientifique de Bibracte (Vincent Guichard, directeur scientifique)