The general objective of the PEACETIME cruise is to study the fundamental processes and their interactions at the ocean-atmosphere interface, occurring after atmospheric deposition (especially Saharan dust) in the Mediterranean Sea, and how these processes impact the functioning of the pelagic ecosystem. During the proposed 33 days cruise in the western and central Mediterranean Sea in May 2017, we will study the impact of atmospheric deposition on the cycles of chemical elements, on marine biogeochemical processes and fluxes, on marine aerosols emission and how ongoing changes will impact the functioning of Mediterranean Sea communities in the future. The cruise is designed to explore a variety of oligotrophic regimes. Combining in situ observations both in the atmosphere and the ocean, and in situ and minicosm-based on-board process studies, the 40 embarking scientists from atmosphere and ocean sciences will characterize the chemical, biological and physical/optical properties of both the atmosphere and the sea-surface microlayer, mixed layer and deeper waters. The PEACETIME strategy (season and cruise track) associated to a combination of dust transport forecasting tools and near real-time satellite remote sensing is designed to maximize the probability to catch a Saharan dust deposition event in a stratified water column in order to follow the associated processes in-situ. This coordinated multidisciplinary effort will allow us to fill the current weaknesses/lacks in our knowledge of atmospheric deposition impact in the ocean and feedbacks to the atmosphere in such oligotrophic systems. As a key joint-project between MERMEX and CHARMEX : The PEACETIME project comes in the scope of the regional multidisciplinaryprogramme MISTRALS (Mediterranean Integrated STudies at Regional And Local Scales ), which aims at predicting the evolution of this region following strong expected changes in climate and human pressures. In this framework, the PEACETIME project constitutes a key joint project between the ChArMEx (the Chemistry-Aerosol Mediterranean Experiment) and MERMEx (Marine Ecosystems Response in the Mediterranean Experiment) initiatives, enabling to gather communities of atmospheric chemists and marine biogeochemists around the common question of assessing the impact of atmospheric deposition on the marine biogeochemical processes and air-sea exchanges.

The BenthOBS dataset includes long-term time series on marine benthic macrofauna, since 1967, along the whole French metropolitan coast. It includes 20 sampling location. BenthOBS aims to establish a national network for the observation of macrozoobenthos. In a context of global change, It is essential to have time series capable of highlighting and understanding ongoing changes in the specific diversity within communities and their consequences on the functioning of marine ecosystems. The BenthOBS network provides the scientific community and stackers with validated data on the following parameters: specific abundance, sediment size composition, sediment organic matter, sediment C content, sediment N content.

French benthic invertebrates composition and abundance taxa data are collected during monitoring surveys on the English Channel / Bay of Biscay coasts and Mediterranean coast (Quadrige program code : REBENT_FAU, RSL_FAU). Protocols are implemented in the Water Framework Directive.  Data are transmitted in a Seadatanet format (CDI + ODV) to EMODnet Biology european database. 498 ODV files have been generated from period 01/01/2003 to 31/12/2021.

Reef-building species are recognized as having an important ecological role and as generally enhancing the diversity of benthic organisms in marine habitats.  However, although these ecosystem engineers have a facilitating role for some species, they may exclude or compete with others. The honeycomb worm Sabellaria alveolata (Linnaeus, 1767) is an important foundation species, commonly found from northwest Ireland to northern Mauritania (Curd et al., 2020), whose reef structures increase the physical complexity of the marine benthos, supporting high levels of biodiversity. Local patterns and regional differences in taxonomic and functional diversity were examined in honeycomb worm reefs from ten sites along the northeastern Atlantic to explore variation in diversity across biogeographic regions and the potential effects of environmental drivers. To characterize the functional diversity at each site, a biological trait analysis (BTA) was conducted (Statzner et al., 1994). Here we present the functional trait database used for the benthic macrofauna found to live in association with honeycomb worm reefs. Eight biological traits (divided into 32 modalities) were selected (Table 1), providing information linked to the ecological functions performed by the associated macrofauna. The selected traits provide information on: (i) resource use and availability (by the trophic group of species, e.g. Thrush et al. 2006); (ii) secondary production and the amount of energy and organic matter (OM) produced based on the life cycle of the organisms (including longevity, maximum size and mode of reproduction, e.g. (Cusson and Bourget, 2005; Thrush et al., 2006) and; (iii) the behavior of the species in general [i.e. how these species occupy the environment and contribute to biogeochemical fluxes through habitat, movement, and bioturbation activity at different bathymetric levels, e.g. (Solan et al., 2004; Thrush et al., 2006; Queirós et al., 2013). Species were scored for each trait modality based on their affinity using a fuzzy coding approach (Chevenet et al., 1994), where multiple modalities can be attributed to a species if appropriate, and allowed for the incorporation of intraspecific variability in trait expression. The information concerning polychaetes was derived primarily from Fauchald et al (1979) and Jumars et al (2015). Information on other taxonomic groups was obtained either from databases of biological traits (www.marlin.ac.uk/biotic) or publications (Naylor, 1972; King, 1974; Caine, 1977; Lincoln, 1979; Holdich and Jones, 1983; Smaldon et al., 1993; Ingle, 1996; San Martín, 2003; Southward, 2008; Gil, 2011; Leblanc et al., 2011; Rumbold et al., 2012; San Martín and Worsfold, 2015; Jones et al., 2018). Map indicating the locations of the 10 study sites in the UK, France and Portugal within the four biogeographic provinces defined by Dinter (2001). (All sites were sampled in 8 different stations, except for UK4 where 5 stations were sampled).

Numerous reef-forming species have declined dramatically in the last century, many of which have been insufficiently documented due to anecdotal or hard-to-access information. One of them, the honeycomb worm Sabellaria alveolata (L.) is a tube-building polychaete that can form large reefs, providing important ecosystem services such as coastal protection and habitat provision. It ranges from Scotland to Morocco, yet little is known about its distribution outside of the United Kingdom, where it is protected and where there is a strong heritage of natural history and sustained observations. As a result, online marine biodiversity information systems currently contain haphazardly distributed records of S. alveolata. One of the objectives of the REEHAB project (http://www.honeycombworms.org) was to combine historical records with contemporary data to document changes in the distribution and abundance of S. alveolata. Here we publish the result of the curation of 331 sources, gathered from literature, targeted surveys, local conservation reports, museum specimens, personal communications by authors and by their research teams, national biodiversity information systems (i.e. the UK National Biodiversity Network (NBN), https://nbn.org.uk/) and validated citizen science observations (i.e. https://www.inaturalist.org/). 80% of these records were not previously referenced in any online information system. Additionally, historic field notebooks from Edouard Fischer-Piette and Gustave Gilson were scanned for S. alveolata information and manually entered.  Each of the 21512 S. alveolata records were checked for spatial and taxonomic accuracy, particularly in the English Channel and the North Sea where incorrectly identified observations of intertidal Sabellaria spinulosa were recorded. A further 54 observations are recorded as ‘Sabellaria spp.’ as the available information did not allow for an identification to species level. Many sources reported abundances based on the semi-quantitative SACFOR scale whilst others simply noted its presence, and others still verified both its absence and presence. The result is a curated and comprehensive dataset spanning over two centuries on the past and present global distribution and abundance of S. alveolata. Sabellaria alveolata records projected onto a 50km grid. When SACFOR scale abundance scores were given to occurrence records, the highest abundance value per grid cell was retained.

The PROSOPE (PROductivity of Oceanic PElagic Systems) cruise took place from the 4th of September (Agadir, Morocco) to the 4th of October (Toulon, France) 1999 aboard the RV Thalassa. There were four main scientific objectives: 1, carry out classical process studies, typical of the Joint Global Ocean Flux Study (JGOFS), 2, focus on small scale biogeochemical processes, in particular at a daily scale, 3, study the influence of nitrogen, phosphorus and iron on oceanic fertility and 4, conduct a calibration/validation operation for the SeaWIFS (Sea-viewing Wide Field-of-View Sensor) color sensor. To reach these objectives, the studied areas, as well as the cruise plan, were designed : To investigate different trophic regimes, to investigate systems characterized by different degrees of limitation in nitrogen and phosphorus and to study stable ("steady state") systems for a sufficiently long period. The cruise track encompassed a variety of trophic systems ranging from eutrophic conditions associated to the Moroccan upwelling to the typical ultra-oligotrophic conditions of the eastern Mediterranean sea during summer stratification. Two main types of stations were occupied : - 9 short (4-hour) stations. These sites were occupied around the solar noon and were essentially designed to conduct objectives 1 (JGOFS process studies) and 4 (SeaWIFS validation/calibration) - 3 "long" (5-day) stations, where all four objectives were investigated with a particular emphasis on objectives 2 (processes at a daily scale) and 3 (nutrient resources and oceanic fertility). Between each station, continuous multiparametric (hydrological, optical, biological and chemical) surface acquisitions were performed.

Early-life stages play a key role in the spatio-temporal dynamics of marine populations due to their highly dispersive properties, their sensitivities to environmental factors and their influences on juveniles’ replenishment. However, these stages are difficult to monitor, so that in-situ observations are scarce and disparate, preventing a good understanding of the control they exert on population dynamics. The Mediterranean coastlines have been highly surveyed during the last decades in different sub-regions; yet no effort was made to assemble observations originating from different research projects and countries. Moreover, this sea has been exploited for centuries and is now recognized as a climate-change hotspot, so that it represents an ideal laboratory to address the role of anthropogenic pressures on marine populations. To advance our knowledge, we build an exhaustive compilation of historical data collected over the past decades up to present. From spawning to settlement, it evaluates both egg and larval stages of coastal fishes characterized by bipartite life cycles. This compilation gathers 44 datasets from North-Western Mediterranean countries (including coastlines of Spain, France, Italy, Croatia and Montenegro) over the last three decades (1993-2021) originating from 48 data providers. We consider direct and indirect observations of early-life stages such as otoliths’ data, datasets of settlers and juveniles sampled by underwater visual census, shore seine, hand-nets or light-traps, as well as fish eggs and larvae sampled with plankton nets. All those types of data are harmonized into a uniform dataset that informs on the periods and locations of spawning and settlement. While some sampling techniques directly provide the variables of interests, other methods require a-posteriori estimations based on growth models from the Dynamic Energy Budget (DEB) theory, using taxon-dependent parameters available in the online Add-my-Pet database. Finally, the complete database consists in several taxon, each of them being associated with dates of both spawning and settlement, as well as other information such as the pelagic larval duration, measures of uncertainties and sampling characteristics (location, depth, etc). Statistical analyses of the consolidated database describe the overall coverage of sampling and evaluate the sampling gaps over space and time in order to guide future sampling efforts. In fact, sampling mainly occurs around marine reserves and from May to October. The general coverage of spawning and settlement is then assessed, looking at the differences between observed data (same distribution as sampling) and back-calculated data (nearly uniformly distributed over the year).  Moreover, the overall taxa distribution is described, mainly represented by Sparidae. Thus, this database informs early-life traits and their variability for different coastal fish taxa in the North-Western Mediterranean in order to document their evolution in a changing world. Indeed, this database will be publicly available to help undertake future connectivity and climatic studies.