Climate change has triggered fundamental modifications of marine biotopes in the Arctic Ocean (AO). The decrease in the extent of the ice pack during summer has led to a 20% increase in pan-Arctic primary production (PP) over the last decade. Phytoplankton blooms now occur earlier in several parts of the AO. In other parts, the structure of the phytoplankton community is shifting toward smaller species, typical of more oligotrophic conditions and some species found in warmer waters now migrate into the Arctic Ocean. Phytoplankton grow in the top tens of meters of both ice-free and ice-covered waters. The phytoplankton spring bloom (PSB) that develops at the ice-edge accounts for >50% of annual primary production in the AO, and is generally associated with both large energy transfer to higher trophic levels and export of carbon to the bottom. As well, the culture, health and economic capacity building of Northerners are closely associated with marine resources supported by the PSB. The Arctic PSB develops in the seasonally-covered ice zone (SIZ), the extent of which is expected to increase significantly during the next years, possibly over the whole AO as early as in 2030. How the PSB will actually evolve in this context is unknown. Will it span over the entire AO, and thereby make the AO ecosystems more productive? Will the ongoing modifications in physical properties of the AO rather limit the PSB and PP in general? How will biodiversity respond to and/or impact on those changes? To be able to answer these questions, it is necessary to understand in great detail and quantitatively the physical, chemical and biological processes involved in the preconditioning, development and decline of the PSB. Because this is a transient phenomenon occurring in a remote, complex and harsh environment, such a detailed understanding has not yet been achieved. The general objective of this research project is to understand the dynamics of the PSB and determine its role in the Arctic Ocean of tomorrow, including for human populations. More specifically, we want to 1) understand the key physical, chemical and biological processes that govern the PSB, 2) identify the key phytoplankton species involved in the PSB and model their growth under various environmental conditions, and 3) predict the fate of the PSB and related carbon transfer through the food web and toward the bottom sediments over the next decades. First, a PSB event will be monitored during 2015 in the Baffin Bay from its onset under melting sea ice in May to its conclusion within the seasonal ice zone in July. The distribution of relevant physical, chemical and biological properties will be described at various time and space scales using a fleet of profiling floats and gliders and an autonomous underwater vehicle, all equipped with a suite of physical and bio-optical sensors. Process studies will be conducted from an ice camp and then from a research icebreaker to document phytoplankton growth, nutrient assimilation and the transfer of carbon through the food web and toward the sediment. Second, key phytoplankton species will be isolated and grown in the laboratory under various conditions to model their response to environmental factors and to understand their succession during spring. Third, a coupled physical-biological model will be optimized for simulating the PSB in the Arctic Ocean and for predicting changes in phytoplankton communities and food web dynamics. In parallel, past and present trends in the intensity and spatial distribution of the PSB will be documented using a paleoceanography approach, and using remote sensing. Finally, interviews and bilateral discussion with local Inuit communities will enable the documentation of changing marine productivity from a social perspective and feed into a multi-scale integrated analysis of environment-human interactions.

Albeit by no means new, collaboration in science has recently gained unprecedented momentum and visibility. Commonly presented as “a good thing”, it has become an imperative. This holds especially true for sustainability science, a recent and expanding problem-driven science that focuses on the dynamic interactions between nature and society and aims to create and apply knowledge in support of decision making for sustainable development. Researchers in this field are strongly encouraged to work with colleagues from other disciplines and actors from outside academia. Yet, little is currently known about how collaborations transform the work practices and identities of researchers and contribute to the shift towards more sustainability. COLLAB² will offer both a broad and in-depth view of inter- and transdisciplinary collaborations in sustainability science. It will pursue the four following goals: 1) elaborate a typology of these collaborations, based on a thorough investigation of their characteristics; 2) describe and analyse their dynamics: how they unfold over time, what stimulates or on the contrary hinders them, at various levels; 3) explore their effects on the practices, roles, identities and trajectories of researchers and their collaborators, and their capacity to contribute to the shift towards more sustainability. A fourth cross-cutting goal is to conduct this research and disseminate its results in close association with sustainability scientists and their partners, so that this project about collaboration will itself be highly collaborative (hence the acronym COLLAB²). COLLAB² will explore the full scope of collaborations in sustainability science in three institutional settings aiming to foster them: CNRS’s Zones Ateliers and Observatoires Hommes-Milieux, and biosphere reserves. It will produce a balanced and multi-level analysis of collaborations, and address their different dimensions (material, cognitive, relational and affective) in the long run. A common research framework will be adopted to allow a cross analysis of the data. It will rely on a mixed method, combining bibliometric tools, a national questionnaire that will be disseminated simultaneously in the three institutions, and an ethnographic survey of a sample of diversified collaborative projects. COLLAB² will devote paramount attention to the perspectives of participants in collaborations, which is crucial given the importance of their human factors but has seldom been addressed so far. COLLAB² will bring together six social and life scientists with strong personal experience of collaborations in sustainability science and wanting to explore them together and with other partners. A dyad of collaborators from each institution investigated will be closely associated to the work of the consortium throughout the project. This will enable us to experiment with a process of participative and iterative reflection through the sharing of experiences and ideas beyond the consortium, leading to new knowledge and mutual learning. COLLAB² will thus make an invaluable contribution to the emerging scientific field of collaboration studies. Its results will be disseminated to a large and diversified audience, using well-adapted language and through a wide array of communication channels (articles in academic and technical journals; conferences and seminars; presentations to the institutions investigated; short videos; interactive website). It will help sustainability scientists and their collaborators to identify the factors and effects of collaborations, overcome their inherent difficulties and form a community of practice. It will provide science policymakers and relevant ministries with concrete recommendations to improve collaborations in sustainability science and craft sound research policies in the Anthropocene.

The GEOPRAS consortium comprises seven partners that have been involved for several years in coastal archaeology. Our programme studies the coastal societies of recent Prehistory (Mesolithic and Neolithic) on the French Atlantic shores in order to understand their social and economic organization and the role they play in broader historical dynamics such as neolithization. Characteristics such as the accumulation of goods through storage, specialised modes of production, and the emergence of a social hierarchy or a sedentary lifestyle are often attributed to these coastal populations, on the basis of ethnographic documents from the last two centuries. However, each of these social manifestations must be described according to regional environmental variables, without evolutionary preconceptions. Our research hypothesis is that environmental dynamics have greatly facilitated certain forms of historical evolution. This encourages us to determine with greater precision the nature of these environmental transformations, then to analyse human networks at the continent-ocean interface. The first task will be to restore the environmental benchmarks. During the Mesolithic and Neolithic periods, most coastal landscapes were radically transformed by the sea-level rise and the associated processes of erosion and sedimentation. The coastal environments of the past will be reproduced through a three-level approach combining a large scale (region) with an intermediate scale (nearby landscape) and a local scale (archaeological site). Our consortium proposes a combination of methods suited to different geographical conditions (dunes, rocky coasts, marshlands) around the Bay of Biscay, testing the limits of several of them. To gain the best possible understanding of an "archaeological signal", the GEOPRAS project will focus on developing rapid intervention and rescue methods for archaeology and geoarchaeology. We intend to apply these methods to sites currently being excavated or whose exploration is planned as part of the project, such as foreshore and marshland sites and shell middens. Optimal integrated methods and procedures will be developed for the recording of archaeological remains, which are often ephemeral on foreshores, as well as for sampling, particularly in shell middens. These procedures include geophysical surveys, archaeozoology, micromorphology, geochemistry, taphonomy, metagenomic approaches, and OSL datings. The second task is to study how human societies have managed the land-sea interface. Shell middens have become the emblematic nodes of these coastal Holocene settlements because they contain an abundance of bio-archaeological data. They will be analysed to judge biodiversity as well as food practices. The third task is to understand the specific features of technical systems in a maritime context, especially seafaring. This technical field is at the heart of all the questions raised about the relationships between coastal areas, as well as the decisive features of the various technical systems developed in these areas. To overcome the lack of knowledge of prehistoric watercraft, we suggest an approach, based on three disciplinary poles in permanent interaction: 1) ethnographic and historical references, 2) technological and use-wear analyses of lithic and bone tools, 3) experimentation. In addition to proposing methodological developments, we aim to lay down the conceptual, methodological and technical foundations of a maritime prehistory with procedures adapted to coastal heritage. The results will be included in a handbook of maritime prehistory, to be published in French and English. The involvement of amateur archaeologists, observers, tourists and other citizens in scientific tasks will be anticipated and coordinated by inviting them to take part in the main scientific meetings and, of course, in field operations such as surveys, excavations and experiments.

The main environmental factors of organic coating degradation are well-known: water, temperature, UV, mechanical stress. Within the framework of sustainable development of metallic structures, formulators consequently use natural or accelerated ageing tests to estimate the life time of the coatings. These tests, either monotonous or, nowadays commonly cyclic, impose ageing conditions including generally two or three ageing factors but never simultaneously the four parameters cited above. Moreover, these approaches are mainly based onto ISO standards which are usually far from fundamental physic. The applied mechanical stress generally places the polymer in a plastic deformation state which is remote from the usual service conditions (viscoelastic domain). In a recent study, we applied a visco-elastic stress to the coating in order to conserve its intrinsic properties. We showed that the simultaneous application of the four ageing factors modified in an important way the life time of the organic coatings. So, and for the first time in our knowledge, synergies of coupling are clearly identified. However, the complexity of the coatings formulations does not allow to correctly define the constitutive equations of the physico-chemical behaviour. Indeed, the paint includes charges and internal stresses may develop during the ageing. Furthermore, the polymer also contains various additives which probably interact with products and photo-products of degradation. In order to pursue our research works, we wish to begin a more fundamental study by choosing a "simple", non-charged model polymer. The methodology previously used will be reproduced with the objective to reach the variations of the chemical, physico-chemical and mechanical parameters of the model polymer. First, we will characterize the model polymer, studied as a free film and as a coating applied onto a metallic substrate before ageing. Then, the influence of each ageing factor for the exposure will be clarified to determine the mechanisms of degradation. The various ageing factors will be first applied alone, then coupled between them gradually until the coupling of all of them. The various techniques of characterization (DSC, IRTF, DMA, SIE, mechanical tests) will then allow to reach the variations of the chemical, physico-chemical and mechanical parameters of the model material. So, constitutive equations of the physico-chemical behaviour will be described according to the environmental stresses applied alone or coupled. A complete mechanical study will be realized in order to determine the visco-elastic domain of the system before the ageing. For that purpose, we will perform simulations using finite elements analysis and the model will be adjusted with the constitutive equations of the physico-chemical behaviour. Finally, the evidence of the synergies of coupling and the numerical modelling should allow us to refine the models of lifetime prediction of organic coatings. The expected results are situated upstream to a technological industrial research but the methodology and the conclusions of our study should be welcomed by the actors of the anticorrosion domain who are respectful of the new environmental recommendations.