Angelo Camerlenghi

Vanni Aloisi

Uncovering the Mediterranean salt giant (MEDSALT) -Scientific Networking as incubator of cross-disciplinary research in Earth Sciences

HAL is

tectonically-driven closure of the Atlantic gateway at the present-day Gibraltar strait. This interpretation was successful not only among the scientific community, but also in the public opinion. On one side the progress of scientific research provided additional evidence for the desiccation theory. On another sides, researches questioned the theory, providing alternative interpretation of the geological data, and theoretical arguments supporting a model of salt deposition from a deep brine, assuming a very limited sea level change. Controversial views exist also on the mechanisms that ended the MSC. A catastrophic flood of Atlantic waters from the re-opening of the Atlantic gateway, or a slow mixing with brackish water from the Balck Sea area first before the re-establishment of the normal marine connection with the Atlantic Ocean.

In order to trigger a progress on the MSC, a large international scientific community has promoted the largest co-ordinated research on the MSC since its discovery, clustered around scientific drilling.

COST (European Cooperation in Science and Technology) was identified as the most appropriate tool, as a COST Actions provide tools for networking, training, mobility and dissemination. The network has further promoted one Marie Skłodowska-Curie European Training Network (SALTGIANT) offering 15 PhD fellowship across Europe. New contacts have been activated with a variety of stakeholders, including governmental administrations, non-governmental organizations, the industry, the and indirectly, the society at large, demonstrating the importance that science and society renew a relationship of thrust and confidence. The first important scientific products are released in the scientific literature. In all 200 scientists are working together across disciplines such as geophysics, geology, biology, microbiology, embracing also social sciences, are working together towards a common scientific goal.

THE ORIGIN OF THE CONTROVERSY

The "Messinian Salinity Crisis" (MSC) is regarded as the longest-living scientific controversy in the field of Earth Sciences (e.g. Roveri et al., 2014a). The controversy has its roots in the Apennine mountain chain of Italy, and its ribbon of gypsum-rich rocks that extends discontinuously from Piedmont to Sicily (Fig. 1). The term MSC was introduced in the scientific literature by [START_REF] Selli | Il Messiniano Mayer-Eymar 1867. Proposta di un neostratotipo[END_REF] who made the link between the Apennine gypsum deposits and what he proposed had been a major disruption of the salinity of the Mediterranean Sea during the Messinian stage of the Miocene epoch (now dated between 5.97 to 5.33 million years ago). Gypsum (CaSO4.2H20) was known already in Sellis' times to be a mineral formed by chemical precipitation during the evaporation of seawater. Gypsum is not, however, the only marine evaporitic mineral because seawater contains a complex mixture of dissolved ions. Six ions make up 99% of seawater dissolved salt: Chloride (Cl -), Sodium (Na + ), Magnesium (Mg --), Sulphate (SO4 --), Calcium (Ca --) and Potassium (K + ). Altogether they make up the bulk of marine dissolved salt, equal to about 35 parts per thousands in weight. This means that the complete evaporation of 1 kg of seawater results in the chemical precipitation of 35 grams of salts. Despite small spatial changes in the salinity of the ocean, the concentration ratio among the major dissolved ions is geographically homogeneous. This is due to the rapid mixing of ocean water masses (about 5000 years) compared to the residence time of the major dissolved ions in the ocean (millions of years). As a result, the sequence of precipitation of minerals during the evaporation of seawater is constant: the six major ions combine to produce the precipitation of CaCO3 (calcite), that with a subsequent substitution of Ca ions by Mg may transform to CaMg(CO3)2 (dolomite), CaSO4.2H20 (gypsum ), that by loss of water may transform to CaSO4 (anhydrite), NaCl (halite), and, finally, a series of additional Mg-and Kchlorides, so-called bitter salts KCl (sylvite), KMgCl3 + 6H2O (carnallite), KMg(SO4)Cl + 3H2O (kainite). This sequence of mineral precipitation, that is easily reproduced in the laboratory, occurs also in nature. One well known case is that of salterns, artificial salt ponds that have served throughout human history to harvest halite salt for food conservation. In salterns, seawater is brought to evaporate in a hot and dry climate in a series of shallow artificial ponds. Calcium carbonate and gypsum precipitate first and are discarded; the residual brine is then allowed to precipitate halite taking care that the 'bitter salts', that precipitate last, do not contaminate the halite harvest; the residual, highly concentrated brine is then delivered back to the open sea.

Rock salt is the other naturally occurring salt deposit. Rock salt is found underground and harvested in salt-mines. Amongst the oldest and most famous salt mines are those of Saltzburg, in Austria, that were discovered by the Celts. Salt extracted from these mines was used by the Celts to preserve cod fished in the northern seas, where salt production in salterns was problematic due to a humid climate and limited evaporation. It is this Rock Salt, and the attempt to explain its origin in the Mediterranean Sea, that led to the emergence of the scientific controversy known as the Messinian Salinity Crisis.

The idea that rock salt forms by evaporation of seawater led Selli to interpret the gypsum deposits of the Apennines as the result of a dramatic change in the salinity of the Mediterranean Sea. His reasoning was straightforward and based on solid geological ground: gypsum, although the most Camerlenghi and Aloisi, Uncovering the Mediterranean salt giant….. European Review -submitted 11/02/2019 abundant evaporitic mineral in the Apennines, is often accompanied by calcium carbonate, and, in a few locations in Sicily, Calabria, and Tuscany, by halite. The similarity of this mineral association with the marine evaporitic sequence was striking, and pointed directly to an event of excessive evaporation of the Mediterranean Sea. The large gypsum sequences now outcropping on land had been deposited underwater in what were interpreted as shallow marine environments lying at the periphery of the deep Mediterranean Basin. But the trigger for the exceptional salinity increase was unknown and the exploration of the 4000m-deep Mediterranean marine realm was in its infancythe MSC controversy was yet to come.

SALT GIANTS

Before looking at how the MSC controversy unfolded, it is important to understand the concept of "Salt Giants". Giant, halite-dominated salt accumulations are common on Earth (Fig. 2); they have horizontal dimensions spanning from hundreds to thousands of kilometres, and kilometre-scale thickness; they are present on all continents, and below the seafloor of the Atlantic Ocean, the Mediterranean Sea and the Red Sea. The age of salt giants spans from Paleo-Proterozoic (about two billion years) to the late Miocene (6.0 -5.5 million years). The youngest salt giant on Earth is the Mediterranean Salt Giant.

Salt giants form during two stages of the evolution of oceanic basins according to the Wilson Cycle (Wilson, 1968): during the birth of an ocean, following the continental rifting phase; and during ocean closure, when lithospheric subduction has almost entirely consumed the oceanic crust, leading to incipient collision of the two converging continents. In both cases the following conditions are met: 1) the oceanic basin is surrounded by landmasses, that restrict water exchange with the global ocean through one or more narrow and shallow sills (gateways); and 2) the rate of evaporation exceeds the rate of water input by precipitation and continental runoff. Excess evaporation causes the salinity to rise in the evaporitic basin, leading to the accumulation of rock salt on the seafloor. Salt giants are often mined for industrial purposes. Rock salt is used for highway de-icing, water softening, animal nutrition and food conservation. One additional potential use of salt giants is as storage of dangerous -nuclear or chemical -waste. This is due to the peculiar properties of halite, that has a low density (about 2.16 g cm-3 ), compared to the average density of host rocks, and a very low permeability to ground water. In response to long-term geological stress, creep deformation at the level of the crystal structure results in plastic deformation. With the plastic re-arrangement of its crystalline microfabric and the nearly null water content, halite has been considered as a perfect seal for dangerous waste. Salt is also an effective seal to hydrocarbon fluids (petroleum and gas): hydrocarbons migrating in salt-bearing sedimentary basins are often trapped under impermeable salt seals where they accumulate in industrially-exploitable oil and gas fields.

But rock salt is mobile during burial and rises though the sedimentary overburden, forming salt diapirs that can pierce the earth surface and ocean floors; salt is subject to complex gravity-gliding phenomena causing hundred-meters-thick salt layers to slide downwards from the basin margins to the deep basin floor; salt can fracture, becoming permeable to groundwater, and lose part of its sealing capacity with respect to water. Lastly, the mobility of underground salts, and their solubility in water, makes buried salt deposits a hazard: sink-holes and landslides are often associated with shallow salt deposits, both onshore and offshore.

Salt giants are an important resource -but also a potential hazard -for human activity.

FROM SALINITY CRISIS TO DESICCATION THEORY FOR THE MEDITERRANEAN SEA

The MSC controversy emerged in 1973, when the scientific drilling vessel Glomar Challenger (Fig. 3) of the nascent Deep Sea Drilling Project (DSDP) entered the Mediterranean Sea for the first time. The scientists of this pioneering expedition found evidence that evaporitic rocks, equivalent in age and mineralogy to those described by Selli in the Apennines of Italy, were buried under hundreds of meters of sands and clay below the seafloor of the Mediterranean Sea. Three scientists -Ken Hsü, Bill Ryan, and Maria Bianca Cita -proposed that the salts found in the deep Mediterranean Sea and on the Mediterranean margins had originated simultaneously by seawater evaporation, and that the sea-level of the Mediterranean Sea had lowered during the deposition of the evaporites, exposing the seafloor of the Mediterranean almost entirely (Fig. 4): the theory of the Late Miocene Desiccation of the Mediterranean [START_REF] Hsü | The Late Miocene desiccation of the Mediterranean[END_REF] was born.

There were two fundamental observations to support this theory: 1) the samples of the evaporites recovered by drilling contained "chicken-wire" nodular anhydrite and algal stromatolites that needed light to exist at the time of seawater evaporation, suggesting a subaerial sabkha depositional environment (Fig. 5); and 2) geological and geophysical investigations on the margins of the Mediterranean Sea had revealed the existence of very deep erosional valleys, some of which buried by sediments, extending inland from the major river systems (Rhone, Nile); similar, profound Vshaped mountain incisions now host the southern-Alps lakes Maggiore, Como, Iseo and Garda. These could have been formed only if the water level in the Mediterranean had lowered dramatically and high-school level, according to some as a paradigm. The MSC is described as an extraordinary example of how the Earth system is vulnerable to natural change, and how the interplay between natural climate change and tectonic movements can result in a huge impact on the oceanography, landscape and ecosystems of a huge region of our planet.

However, not all scientists are convinced that in order to precipitate salts at the bottom of a deep oceanic basin, that basin has to desiccate. The salinity of an oceanic basin can increase without a substantial decrease in the volume of water, until the entire water mass has become a dense brine from which salts begin to precipitate chemically [START_REF] Schmalz | Deep-water evaporite deposition, a genetic model[END_REF]. The idea of the desiccation of the Mediterranean was questioned in the literature based on several arguments (e.g. [START_REF] Selli | An outline of the Italian Messinian. In, Messinian Events in the Mediterranean, In, Messinian Events in the Mediterranean[END_REF] later re-proposed by Roveri et al., 2001[START_REF] Lugli | The deep record of the Messinian salinity crisis: Evidence of a non-desiccated Mediterranean Sea[END_REF] and in many other works): the evidence for deep-water environments of deposition in rock outcrops; the interpretation of the deep incised valleys as the product of dense brines sinking and eroding the flanks of the deep Mediterranean basin; and results from paleoceanographic models that can reproduce salinity-increase in a deep water environment using the most probable climatic condition during the Messinian Salinity Crisis (e.g. [START_REF] Bache | A two-step process for the reflooding of the Mediterranean after the Messinian Salinity Crisis[END_REF]Simon and Meijer, 2017). These criticisms added to earlier ideas proposing that the Messinian evaporites had in fact accumulated in a shallow-basin, shallow-water system subject to continuous subsidence under the increasing load of accumulating evaporites [START_REF] Nesteroff | Un Modèle por les évaporites messiniennes en Méditerranée, des bassins peu profonds avec dépots d'évaporites lagunaires. In, Messinian Events in the Mediterranean[END_REF]. Since its birth in 1973, the provocative idea of a deep desiccated Mediterranean has been continuously challenged by part of the scientific community.

A further important disagreement feeding the controversy regards the mechanism by which the Mediterranean Sea returned to normal open marine conditions at the transition from the Miocene to the Pliocene. From the very beginning the proposers of the desiccation theory postulated a dramatic flooding of the Mediterranean when the Gibraltar strait re-opened. The idea of the Gibraltar 'cataracts' attracted the attention of the general public and the press (Fig. 6), and found support from early modelling studies [START_REF] Blanc | The opening of the Plio-Quaternary Gibraltar Strait: assessing the size of a cataclysm[END_REF]. But did a dramatic flooding of the Mediterranean basin take place if there was no substantial sea-level drawdown during the MSC? Further, there is disagreement on the origin of the waters invading the Mediterranean at the end of the MSC. The Messinian evaporites are often covered by a layer of varying thickness of sand, clay, and sometimes gravel, that contain microfossils typical of shallow-water, brackish environments. These microfossils originate from the East of the Mediterranean, from the so called 'Paratethis basin', that in Messinian times occupied the present-day Carpathian and Black Sea areas (e.g. [START_REF] Krijgsman | Rise and fall of the Paratethys Sea during the Messinian Salinity Crisis[END_REF]. Theses sediments are referred to in the literature as 'Lago-Mare' and represent perhaps the biggest unknown in the whole controversy. The Lago-Mare deposits imply that after the high-salinity phase during which the evaporites accumulated, there followed a low-salinity stage that preluded to the end of the crisis. The Lago-Mare sediments have been found also in the Western Mediterranean, imposing a scenario of a Mediterranean-wide low-salinity phase fed from waters spreading from the Levant Sea, or the Aegean.

More than 1800 research articles have been published about the MSC, but no consensus exists on the tectonic, climatic and hydro-geo-chemical processes that led to the deposition of the Messinian evaporites and returned the Mediterranean to normal marine conditions at the end of the salinity crisis. Marine geophysical exploration led to the Mediterranean-wide mapping of salt deposits, providing unprecedented information of their extent and internal structure (Fig. 7). Estimates of the total volume of salts deposited during the MSC are under way. It is likely that the total amount of salts will exceed ~ 1 million cubic kilometres, corresponding to more than 6% of the dissolved salt in the global ocean. We now know that the evaporitic deposits resting in the deep basins of the Mediterranean are laterally heterogeneous. While gypsum accumulated preferentially in the western Mediterranean basin, the eastern Mediterranean evaporitic succession is composed nearly exclusively of halite (e.g.

THE CONTROVERSY TODAY

Today

Commented [GA1]:

Nuovi approcci scientifici => nuovi dati => conoscenza della MSC migliore ora rispetto agli anni '70. Ma le nuove idee sono criticate, e questi nuovi sviluppi non riescono a risolvere la cotroversia [START_REF] Lofi | Seismic Atlas of the Messinian Salinity Crisis Markers in the Mediterranean Sea, Vol. 2 72 pages + DVD[END_REF]. The origin of this huge-scale chemical distillation is still unknown. Geophysical surveys have produced extraordinary images of the deep valley and canyon systems, at times resembling proper fluvial systems, at the margins of the Messinian basins offshore the Ebro River (Urgeles et al., 2010), the northern Adriatic [START_REF] Ghielmi | Late MioceneeMiddle Pleistocene sequences in the Po Plain e Northern Adriatic Sea (Italy): The stratigraphic record of modification phases affecting a complex foreland basin[END_REF], the Sirte Gulf [START_REF] Bowman | A comprehensive review of the MSC facies and their origins in the offshore Sirt Basin, Libya[END_REF], and the Lebanon Margin [START_REF] Madof | Discovery of vast fluvial deposits provides evidence for drawdown during the late Miocene Messinian salinity crisis[END_REF]Fig. 8). These are interpreted as the erosional incisions that developed when peri-Mediterranean rivers were rejuvenated by the fall of Mediterranean Sea-level.

Finally, improved images of the subsurface geological structure in the Ionian Sea have allowed identifying what is thought to be the mega-flood deposit that accumulated at the Sicilian sill when the Mediterranean basin was reconnected with the Atlantic Ocean at the end of the MSC (e.g. [START_REF] Micallef | Evidence of the Zanclean megaflood in the eastern Mediterranean Basin[END_REF].

Geochemical and biological proxies -measurable characteristics of sediments that inform on past environmental conditions -highlight what seems to be a complex evolution of hydrology and salinity during the MSC. The strontium isotope composition of MSC evaporites from the deep and marginal Mediterranean basins point to a substantial freshwater input during the last phases of the MSC culminating with the Lago-Mare unit (Topper et al., 2001;Roveri et al., 2014a). Molecular biomarkers and their hydrogen isotope composition confirm this scenario, and suggest that the freshwater pulse originated via overspill of the Parathetys into the eastern Mediterranean (e.g. Vasiliev et al., 2017;[START_REF] Madof | Discovery of vast fluvial deposits provides evidence for drawdown during the late Miocene Messinian salinity crisis[END_REF]. But the influence of freshwater during evaporite deposition is not limited to the final stages of the MSC. What seem to be local influxes of freshwater characterize marginal basins of the Mediterranean also during the first phase of the MSC, when extensive gypsum successions such as those of the Apennines were being deposited. Evidence comes from salinity measured in gypsum fluid inclusions [START_REF] Natalicchio | Did the Late Miocene (Messinian) gypsum precipitate from evaporated marine brines? Insights from the Piedmont Basin (Italy)[END_REF], and from the oxygen and hydrogen isotopes of gypsumbound water [START_REF] Evans | Coupled measurements of d 18 O and dD of hydration water and salinity of fluid inclusions in gypsum from the Messinian Yesares Member, Sorbas Basin (SE Spain)[END_REF], indicating that basin salinity was at times lower that of ocean waters (35 g/kg). The process of formation of this "low-salinity gypsum" remains unknown.

In the absence of lithological samples from the deep basin, numerical modelling has proven to be a powerful tool to test ideas on the hydro-geo-chemical and geo-tectonic evolution of the Mediterranean basin during the MSC. Paloeceanographic modelling is providing support to the various MSC scenarios, demonstrating the importance played by paleo-climate, paleo topography and the paleo-hydrological budget of the Messinian Mediterranean Basin (Simon et al., 2017;[START_REF] Flecker | Evolution of the late Miocene Mediterranean-Atlantic gateways and their impact on regional and global environmental change[END_REF][START_REF] Marzocchi | Mediterranean outflow pump: An alternative mechanism for the Lago-mare and the end of the Messinian Salinity Crisis[END_REF]. The geometry and evolution of the Atlantic-Mediterranean gateway have been demonstrated to be crucial to the full understanding of the precursory events that led to the onset of the salinity crisis [START_REF] Flecker | Evolution of the late Miocene Mediterranean-Atlantic gateways and their impact on regional and global environmental change[END_REF]. 3D restoration modelling of the Messinian paleo topography, supported by geological and geophysical data, suggests the existence of an isolated, relatively deep Messinian Basin below the present Po Plain and Northern Adriatic [START_REF] Amadori | Restored topography of the Po Plain-Northern Adriatic region during the Messinian base-level drop -Implications for the physiography and compartmentalization of the palaeo-Mediterranean basin[END_REF]: the Messinian Mediterranean could have consisted of numerous distinct, and at times interconnected, basins, each with its own topographic and hydrologic character. Modelling of sediment erosion and flux rates at Gibraltar during the postulated Atlantic reflooding that terminated the salinity crisis has open astonishing scenarios for a nearly instantaneous event that refilled the entire Mediterranean [START_REF] Garcia-Castellanos | Catastrophic flood of the Mediterranean after the Messinian salinity crisis[END_REF].

But numerical models lack the fundamental constraints provided by the lithological, biostratigraphic and geochemical analyses of evaporites and related sediments in the deep Mediterranean basins. It is no surprise then that the hypotheses put forward with the dataset available today are continuously challenged scientifically. The deep erosional valleys at the basin margins, interpreted by the author as evidence of sea level lowering, are re-interpreted by some as the product of margin erosion by sinking brines, and therefore as subaqueous features (e.g. Roveri et al., 2014b). Erosional truncations found at the top of the salts in the Levantine basin, generally interpreted as the product of salt gravitation gliding and erosion, are interpreted as subaqueous dissolution [START_REF] Gvirtzman | Intra-Messinian truncation surface in the Levant Basin explained by subaqueous dissolution[END_REF]. The geochemical signals pointing to substantial influence of freshwater during the deposition of gypsum in the marginal basins could have been modified by post-depositional mineral dissolution/re-precipitation processes. At present, scientists agree to state that the controversy has no solution unless new data, in particular from the deep basins, is acquired and integrated to evaluate existing -or novel -MSC scenarios.

Finally, a growing scientific discipline in relation to the MSC is considering the impact of a sea-level decrease on the faunal migration taking advantage of temporary natural land bridges caused by sealevel lowering (e.g. [START_REF] Mas | Terrestrial colonization of the Balearic Islands: New evidence for the Mediterranean sea-level drawdown during the Messinian Salinity Crisis[END_REF].

A DEEP, SALTY BIOSPHERE?

There is a biological twist to the MSC story: the Mediterranean Salt Giant might contain a deep biosphere of microbes that is phylogenetically diverse, metabolically active and characterised by exceptional longevity (Fig. 9). In the past 15 years, scientific drilling has shown that microbes are present down to 2466 meters below sea floor in a diverse set of geological environments [START_REF] Roussel | Extending the sub-sea-floor biosphere[END_REF][START_REF] Colwell | Nature and Extent of the Deep Biosphere[END_REF][START_REF] Orcutt | Microbial activity in the marine deep biosphere: progress and prospects[END_REF][START_REF] Inagaki | Exploring deep microbial life in coal-bearing sediment down to ~2.5 km below the ocean floor[END_REF]. Although the biosphere of deeply buried salt deposits has never been studied, recent investigations suggest that microbes living in the Mediterranean Salt Giant are involved in extensive mineral transformations that both provide oxidative energy for life and are the driving force for the development of microbial diversity. Evidence comes from the microbiological and geochemical study of evaporitic deposits, including those outcropping on the margins of the Mediterranean. These investigations suggest that subsurface gypsum accumulations promote the development of deep biosphere communities of sulphate reducing microbes. These thrive on the reduction of gypsum and anhydrite-derived sulphate and the concomitant oxidation of reduced organic carbon compounds such as methane, petroleum and organic matter (Fig. 9A) [START_REF] Aloisi | Biomarker and isotope evidence for microbially-mediated carbonate formation from gypsum and petroleum hydrocarbons[END_REF][START_REF] Peckmann | Bacterially mediated formation of diagenetic aragonite and native sulfur in Zechstein carbonates (Upper Permian, Central Germany)[END_REF]Ziegenbalg et al., 2012). This process has implications for sedimentary biogeochemical cycles, the souring of crude oil and the formation of the enigmatic mineral dolomite, one of the long-standing controversies in Earth Sciences.

The thickness of the Messinian evaporites and the range of chemical environments it harbours poses fundamental questions: will the interaction of several extreme environmental parameters like temperature, salinity, pressure and chemical composition limit the ability of microbes to take advantage of such favourable thermodynamic conditions? And has such a diverse set of physical and chemical environments fostered microbial diversity, rather than phylogenetic specialization, as research into deep Mediterranean brine systems seems to indicate [START_REF] Daffonchio | Stratified prokaryote network in the oxic-anoxic transition of a deep-sea halocline[END_REF]? Dwelling in up to three kilometres in salt thickness, close to the known temperature limits of life and with fluids associated to carbonate, sulphate, halite and potash salts, microbes living within and around the MSC salt giant will be subject to the most exotic combinations of extremes, and are likely to have evolved as yet unknown adaptations.

Gypsum and halite crystals contain fluid inclusions that are a micro-habitat in which microbes survive for tens of thousands, to possibly millions, of years (Fig. 9C) (McGenity et al., 2010;[START_REF] Schubert | How do prokaryotes survive in fluid inclusions in halite for 30,000 years?[END_REF]. This poses fundamental questions about whether cells can devote nearly all of their energy flow to somatic maintenance needs, rather than growth and reproduction, and opens new avenues of research concerning life on other planets. Fluid inclusions and the microbes they contain also inform us on the chemical and physical conditions of the sedimentary environment at the time of formation. Mediterranean gypsum of Messinian age outcropping in the Vena del Gesso (central Italy) contains what could be the most ancient known cyanobacterial RNA [START_REF] Panieri | Ribosomal RNA gene fragments from fossilized cyanobacteria identified in primary gypsum from the late Miocene, Italy[END_REF] (Fig. 9B), suggesting deposition of gypsum under a shallow, illuminated water column. Fossil filaments trapped in Messinian gypsum crystals outcropping in the Tertiary Piedmont Basin (North West Italy), on the other hand, are thought to be the remains of microbes capable of oxidising H2S (Dela [START_REF] Pierre | Are the large filamentous microfossils preserved in Messinian gypsum colorless sulfide-oxidizing bacteria ?[END_REF], a proof of an active biogeochemical sulphur cycle at the time of gypsum deposition. These exciting questions about life in salt lie at the core of a new set of international initiatives that have the goal of solving the open controversy.

NEW PERSPECTIVES AND THE POWER OF SCIENTIFIC NETWORKING

After a second DSDP expedition had drilled the Messinian evaporites in 1978, scientific drilling operations stopped. The possibility to intersect hydrocarbon pockets, or karstic holes, and the dissolution the salts surrounding the drilling pipes, were considered as drilling hazard -penetration into the evaporites was limited to 50 m. With such a drastic technological limitation, scientists did not identify scientific drilling as an opportunity to improve the knowledge on the MSC for decades.

The international scientific community decided to change this situation of 'stall'. During the milestone workshop "The Messinian Salinity Crisis from mega-deposits to microbiology" held in Almeria, Spain in 2007(CIESM, 2007), scientists concluded, based on the observations and data available, that the new input that will enable this change lies in samples and geophysical data to be In 2014, a second workshop was held in Paris to prepare the Multi-phase Drilling Project called "Uncovering a Salt Giant" that serves as an "umbrella" proposal under which the scientific questions posed by the MSC are submitted to the IODP scientific review system. The umbrella approach implies the submission of additional site-specific drilling proposals addressing not only the MSC, but also salt tectonics and fluids, surface-to deep-Earth connections, and the deep biosphere. The approach identified is that of multi-platform drilling, with some sites accessible only with the drilling vessel Chikyu in riser mode, and others accessible with the riser-less JOIDES Resolution.

At the same time, the stakeholders of scientific drilling through the Mediterranean salt giant felt the need to cluster in a stable scientific network to face all the preparatory phases for the projects. COST

  Camerlenghi and Aloisi, Uncovering the Mediterranean salt giant….. European Review -submitted 11/02/2019 6 during the salinity crisis. The trigger of the MSC was identified as the partial, or complete, closure of the Miocene-time Gibraltar Strait combined with a negative hydrological balance of the Mediterranean-Black Sea hydrographic basin. The theory of the Late Miocene Desiccation of the Mediterranean Sea received world-wide attention, both by the scientific community and by the general public. It has entered the textbooks at university

  , nearly 50 years after the beginning of the controversy, no new Messinian evaporite outcrops have been discovered on land, nor new scientific drilling has taken place a sea. The MSC controversy remains unsolved. Nevertheless, substantial progress has been made in understanding selected aspects of the MSC thanks to: (1) a dramatic technological improvement of marine geophysical exploration methods and the collaboration between private hydrocarbon sector companies and public sector research institutes; (2) the development and widespread utilization of geochemical and biological proxies of the environmental conditions at the time of evaporite deposition; and (3) the development of numerical models that simulate the hydro-geo-chemical evolution of the Mediterranean basin during the MSC.

  Camerlenghi and Aloisi, Uncovering the Mediterranean salt giant….. European Review -submitted 11/02/2019 10

  obtained in a new phase of scientific drilling. The availability starting from 2003 of the riser-drilling vessel Chikyu, owned by the Japanese partner of the Integrated Ocean Drilling Project (IODP), restored the hope for change. With a riser-drilling rig, R/V Chikyu can attempt drilling into the salts that the riser-less drilling rig of the ship JOIDES Resolution was not permitted to penetrate. A couple of drilling projects were submitted to IODP for approval in the years 2000s but were not considered for scheduling. Furthermore, R/V Chikyu was busy carrying out long-term drilling programs in the Pacific Ocean, with no real opportunities to be deployed in the Mediterranean area. More recently, a renewed push to build a global scientific network unifying the different schools of thought on the Messinian Salinity Crisis led to a road map elaborated during two workshops sponsored by ECORD, the European Consortium for Ocean Research Drilling. This initiative goes under the acronym of DREAM (Deep Sea Record of Mediterranean Messinian Events). In 2013, in Brisighella (Italy), three generations of scientists (those who participated in the discovery, those who were actively involved in research at the time, and the next generation) met to identify locations for multiple-site drilling in the Mediterranean Sea that would allow to solve the open questions posed by the MSC. It was the start-up of the largest co-ordinated research on the Messinian Event since its discovery, clustered around ECORD and IODP. It was an honour for all of us attending the Brisighella meeting to discuss the future of MSC research together with Ken Shu, Bill Ryan and Maria Bianca Cita (Fig. 10). The participants agreed that given the complexities of the distribution of the Messinian seismic markers in the Mediterranean, and because of the differences in the paleoceanographic conditions in the Mediterranean between the Western and Eastern basins, the drilling strategy must include multiple sites covering representative locations of both Western and Eastern Mediterranean basins.

(

  European Cooperation in Science and Technology, https://www.cost.eu/) was identified as the most appropriate tool, as a COST Actions provide tools for networking, training, mobility and dissemination. COST Action CA15103 Uncovering the Mediterranean salt giant (MEDSALT) was launched in March 2016 and includes 20 COST Countries, 8 Institutions from COST Near Neighbour Countries, Japan, and the USA. Associated to this was another network, similarly called MEDSALT, funded by the French Agence Nationale de la Recherche (ANR) with the purpose of supporting the preparation of scientific drilling proposals. The four overarching scientific objectives of COST action MEDSALT are: 1. to understand salt giant formation and its relationship with local, regional and global environmental change; 2. to investigate salt dynamics and associated fluid flow quantitatively in order to assess geohazards; 3. to understand if salt giants promote the development of metabolically active and phylogenetically diverse deep biosphere communities of microbes and viruses; 4. to model the isostatic response of the lithosphere to extreme and rapid mass transfer and to kilometre-scale differential vertical motions of the Mediterranean margins. The strategy behind successful scientific networking in MEDSALT is based on the following points: Global implications of the MSC. Scientific networks should address the causes, timing, emplacement mechanisms, and consequences at local and planetary scale of the largest and most recent 'salt giant' on Earth; Technological challenge. The technological developments in drilling salt and the possibility that the IODP will bring its platforms to the Mediterranean area have pushed scientific and industrial interests in Mediterranean salt and sub-salt geological environment to converge; Projection into the deep biosphere. The rising interest in exploring microbial diversity in deep, extreme environments supports the biological exploration of the high salinity, high pressure, and high H2S environments most likely to be encountered in the deep sedimentary record of the MSC. The ongoing MEDSALT scientific cooperation is largely inter-sectorial and multinational, comprising a critical mass of both experienced and early-career researchers from Europe and beyond. The goals are addressed through capacity building, researchers' mobility, skills development, knowledge exchange. The network today is working as an incubator of new ideas and new initiatives, and is providing a framework for the management of the drilling initiatives derived from the success of the umbrella drilling proposal. To date, there are three site-specific scientific drilling proposal under evaluation by IODP (Fig. 11), with a good chance to be transformed in scientific drilling expeditions before 2023. The MEDSALT Incubator has not only produced and managed the drilling plans: it is training the next generation of scientists that will contribute to implement drilling projects. Training is taking place through the Marie Skłodowska-Curie Innovative Training Networks (ITN) "SALTGIANT -Understanding the Mediterranean Salt Giant", that was launched in February 2018 (https://www.saltgiant-etn.com). SALTGIANT brings together a diverse group of researchers from Europe and beyond in order to train a new generation of outstanding scientists at the frontier between natural and social, fundamental and applied sciences, all focussing on the understanding of an exceptional natural event and to understand the far-reaching implications it has for fundamental science, industry and society. The SALTGIANT program provides 15 PhD students with a crossdisciplinary, high-end scientific expertise, with access to state-of-the-art experimental facilities and field laboratories, and collaborations with the oil, mining and biotechnology industries that will enable them to address our ambitious research goals. More ideas are in the MEDSALT incubator: to expand the drilling plan to the continental realm, addressed by the International Continental Drilling Project (ICDP); Integrate the knowledge gathered on the Mediterranean Salt giant (the youngest on Earth) to older salt giants, including the oldest on Earth (Onega Basin in Russian Karelia Paleoproterozoic era, 2.5 to 1.6 billion years ago); communicate to the different sectors of our society what are the scientific challenges in the Earth and biological sciences. The latter is becoming an urgent need for science and society. Scientific drilling and the geophysical exploration of the Earth subsurface (weather on land or below the oceans) is too often perceived by citizens as the precursor of industrial mining and hydrocarbon extraction operations. The legitimate ambitions of society to implement a sustainable carbon-free economy with minimum impact on the natural environment sometimes generate conflicts with the ambitions of scientific research, which shares tools, investigation techniques, and scientific knowledge with the industry. All parties should make an effort to maintain an open and transparent dialogue, based on scientific knowledge, sharing of information, and mutual trust in order to guarantee the progress of science and society.

Simon, D., Meijer, P., 2015. Dimensions of the Atlantic-Mediterranean connection that caused the Messinian Salinity Crisis. Marine Geology 364, 53-64. Simon and Meijer, P., 2017. Salinity stratification of the Mediterranean Sea during the Messinian crisis: A first model analysis. Earth and Planetary Science Letters, 479, 366-376. Simon, D., Marzocchi, A., Flecker, R., Lunt, D.J., Hilgen, F.J., Meijer, P.T., 2017. Quantifying the Mediterranean freshwater budget throughout the late Miocene: New implications for sapropel formation and the Messinian Salinity Crisis. Earth and Planetary Science Letters 472, 25-37. Topper, R.P.M., Flecker,R., Meijer,P., Wortel,M.J.R., 2011. A box model of the Miocene Mediterranean Sea: implications from combined 87Sr/86Sr and salinity data. Paleoceanography 26 (PA3223). Urgeles, R., Camerlenghi, A., García-Castellanos, D., De Mol, B., Garcés, M., Verges, J., Haslam, I., Hardman, M., 2010. New constraints on the Messinian sealevel drawdown from 3D seismic data of the Ebro Margin, western Mediterranean. Basin Research, doi/10.1111/j.1365-2117.2010.00477.x Vasiliev I., Mezger, E.M., Lugli, S., Reichart, G.-I., Manzi, V., and Roveri, M., 2017. How dry was the Mediterranean during the Messinian salinity crisis? Palaeogeography, Palaeoclimatology, Palaeoecology 471, 120-133. Vasiliev, I., Karakitsios, V., Bouloubassi, I., Agiadi, K., Kontakiotis, G., Antonarakou, A., Triantaphyllou, M., Gogou, A., Kafousia, N., de Rafélis, M., Zarkogiannis, S., Kaczmar, F., Parinos, C., and Pasadakis, N., 2019. Large sea surface temperature, salinity, and productivity-preservation changes preceding the onset of the Messinian Salinity Crisis in the eastern Mediterranean Sea. Paleoceanography and Paleoclimatology, https://doi.org/10.1029/2018PA003438. Warren, J.K., 2010. Evaporites through time: tectonic, climatic and eustatic controls in marine nonmarine deposits. Earth-Science Review, 98, 217-268.

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Luz Adriana Bustamante Perez

Mickael Ehrminger

Lucia Romo

Le Sevrage

Le sevrage tabagique assisté par l'utilisation d'une application mobile : le rôle de l'engagement

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Parmi les solutions récentes, les applications mobiles semblent être un moyen prometteur pour favoriser un sevrage tabagique réussi. Toutefois, il n' existe que peu de données sur leur impact à long terme, et les déterminants d'une utilisation régulière de ces applications par les personnes désirant de fumer sont mal connus. Or, l'utilisation régulière d'un outil d' aide à la thérapie serait un déterminant important de la réussite du sevrage.

  Le sevrage tabagique assisté par l'utilisation d'une application mobile Resultats Les résultats seront présentés selon le Modèle d' Acceptation de Technologie (TAM II) basé sur la norme subjective, l'utilité et d'utilisation perçues. Nous évaluerons le nombre d'utilisateurs lançant l' application une seule fois ceux s'y engageant régulièrement après l' avoir évaluée. Pour évaluer l'impact de l'utilisation régulière de l' nous demanderons la date d' arrêt des utilisateurs et suivrons l' évolution de leur consommation. Protocole : Détérminants d'une mobile pour le sevrage tabagique Discussion Un collectif attendu avec l' amélioration des connaissances sur les facteurs impactant l'utilisation régulière d'une application mobile et l'impact de cette utilisation sur le sevrage tabagique.

Cette recherche a été par une convention dans le cadre " Territoires de Santé de Demain " par l'Eurométropole de Strasbourg avec un numéro de référence de : TSD-AMI2-2.13, et le contrat thèse de Luz Adriana BUSTAMANTE, psychologue TCC est financé par l'Association Nationale de Recherche et de la Technologie (ANRT), avec un numéro de référence CIFRE : 2019/0078.

Première utilisation

Engagement Functionnalité Esthétique Information