Pierre Lejeune

• Station de Recherche Océanographiques et Sous-marines

Blue Haslea species are marine benthic pennate diatoms able to synthesize a blue-green water-soluble pigment, like marennine produced by H. ostrearia Simonsen. New species of Haslea synthetizing blue pigments were recently described (H. karadagensis, H. nusantara, H. provincialis and H. silbo). Their marennine-like pigments have allelopathic, antio...

Marine communities are often affected by intense fishing pressure, and the related impacts can be detected and understood through bioindicators that assess stock biomass, the state of exploitation, species diversity, the average trophic level of catch, and changes in the catch mass. Here we apply a series of bioindicators to small-scale fishery cat...

Port areas are socio-ecosystems impacted by chronic mixture pollution. Some marine species benefit from living there and may be studied to define the ecological state of such environments. In this study, the risks of chronic chemical contamination and its consequences on three marine molluscs were evaluated in North Corsica (France) port areas. Med...

Pollution particularly affects coastal ecosystems due to their proximity to anthropic sources. Among those environments, harbours are subjected to marine traffic but also to accidental and chronic pollution. These areas are thus exposed to complex mixtures of contaminants such as trace elements and organic contaminants which can impact marine speci...

In port areas the identification of contamination sources is necessary for an efficient management. Biomonitoring provides information on the environmental impact of the pollutants. It is often difficult to differentiate the natural variations of biomarkers from those induced by pollution. The present study aims to define a baseline level for bioch...

In Mediterranean, Posidonia oceanica develops a belowground complex structure ('matte') able to store large amounts of carbon over thousands of years. The inventory of blue carbon stocks requires the coupling of mapping techniques and in situ sediment sampling to assess the size and the variability of these stocks. This study aims to quantify the o...

Between 1948 and 1965, the Canari asbestos mine (Corsica, France) discharged 11 million tonnes of serpentinite rubble into the sea. This study, therefore, aims to assess the environmental and health risks associated with contamination of potentially toxic elements using bioindicators (seagrass and fish) in the areas bordering the former mine within...

FAIR and open data is not a simple, static and achievable one-step process. Challenges emerge when structuring, sharing and opening up research data, multidisciplinary in particular. An iterative approach is necessary, above all, to achieve sufficient formalism for the data to be readable also by machines and to comply with the requirements of the...

Coastal harbor areas are subjected to a myriad of contamination sources with largely unknown effects. Such complex chemical mixtures are difficult to monitor but transcriptomics is a promising approach for such biomonitoring. The present study was designed to verify the use of the Coastal Biosensor for Endocrine Disruption (C-BED) assay, previously...

Improving the effectiveness of marine spatial management is crucial to preserve marine ecosystems and also to support the fisheries economy. In this study, we aimed to determine the spatial distribution and suitable habitats (spawning and nursery sites) of Sciaena umbra and Dentex dentex using catches data in Corsica Island. Random forest models ha...

The Eastern Corsican Coast (ECC) is distinguished by its shallow sandy shelf, extensive Posidonia seagrass meadows, and the relatively limited exploitation of fish in this region. To understand ECC trophic functioning and the effects of fishing in this region of the Mediterranean Sea, we applied the Ecopath and EcoTroph approaches. Our model encomp...

Health councils recommend a higher consumption of aquatic resources because of the health benefits associated with these kinds of food. Due to its nutritional quality, fish derived from marine environment is one of the major contributors to a healthy human nutrition. This study aims to assess the fatty acid profile and nutritional composition of cu...

Coastal port areas are subjected to a myriad of pollution sources. Contaminants in such systems include legacy pollutants (metals and hydrocarbons) and emerging contaminants (e.g. pharmaceuticals) with largely unknown effects. Monitoring for such complex chemical mixtures in marine ecosystems is difficult. Transcriptomics is a promising approach ap...

Les pollutions présentes en mer (organiques et inorganiques), proviennent à plus de 80% du domaine terrestre et des activités humaines qui y sont menées. Les eaux côtières, regroupant pas moins de 90% de la biodiversité marine, sont directement impactées par ces pressions anthropiques. Plus particulièrement, les zones portuaires, qui abritent bons...

Small-scale fishery represents 83% of the Mediterranean fleet. Yet, its evaluation is made difficult by a scattered fishing effort, especially on large islands with remote fishing harbours. Corsica is considered as one of the area with the lowest fishing pressure in the Mediterranean and is mainly characterized by a small-scale fishery (SSF). The p...

1. Sound production represents an integral part of social communication in many teleost fish; however, few studies have investigated the structure, organization and variability of fish sounds at the community level. 2. Fish acoustic community structure was recorded simultaneously in three sites located along the Mediterranean basin within the ende...

Le biomonitoring du milieu marin, mis en place pour caractériser l’état écologique d’un milieu, ou évaluer les effets des protocoles de gestion environnementale, permet le développement d'une compréhension scientifique de l'environnement marin et des impacts des humains sur celui-ci. Les méthodes traditionnelles de biomonitoring sont généralement b...

Dans les zones portuaires, les divers polluants retrouvés dans le milieu constituent une menace sérieuse pour le milieu marin et les espèces qui y résident [1]. Les activités récréatives, le trafic maritime, le carénage, etc. provoquent une contamination qui s'ajoute à celle déjà observée en zone côtière. Ces pressions anthropiques chroniques peuve...

Human activities, whether at sea, on land or along the human‐made coastline may cause chronic and diffuse pollution in the marine environment that represents 75% of the global marine pollution. The use of bioindicators is particularly relevant from a biological point of view if the directly measured concentrations reflect the bioavailable fractions...

Macroalgae play a structuring role in benthic ecosystems, which makes it very important to monitor their cover rates and study their community structures and changes in time. Such studies are usually led by autonomous divers and often do not generate sufficient data to provide enough material for strategically-sound conservation plans. This paper d...

Coastal fishes are not only valuable elements of marine biodiversity, but they also play an important ecological role in the functioning of coastal ecosystems: food resource, transfer of nutrients, predators. Therefore, data on the compositions of fish assemblages are of great importance. The objectives of the present study were to (i) define the f...

Les zones portuaires sont des socio-écosystèmes anthropisés soumis à l’influence des bassins versants et à une forte urbanisation. Ces environnements semi-fermés sont impactés par des polluants (organiques et inorganiques) liés à la dynamique spécifique des ports (trafic maritime, activités de pêche, plaisance, peintures antisalissures). Malgré ces...

This work is a part of PADDUC CHANGE program whose aim is to monitor of major Blue Carbon Ecosystems to ensure their conservation and assessment of the role of these Blue Carbon Ecosystems with regard to the overall Carbon balance of the Corsica Region, with the possible enhancement of this sink. The main target of this work was to evaluate the car...

Marine aquaculture provides undoubted economic benefits and diverts a proportion of fishing pressure on wild stocks. However, it is known to strongly impact marine life with the Mediterranean region, which is densely populated and urbanized with a strong demand for seafood, especially sensitive to marine aquaculture pressures. Marine aquaculture no...

The common spiny lobster (Palinurus elephas, Fabricius, 1787) is an iconic species of the Mediterranean Sea. Despite the existence of data on the artisanal fishery of P. elephas in the Mediterranean Sea and particularly in Corsica, knowledge on the biology and life history traits of this iconic species is still lacking. This paper identifies the ma...

Coastal areas are the interface between terrestrial and marine ecosystems and are a habitat for 90% of the marine biodiversity. However, these waters are the first impacted by anthropic activities, especially in port areas, due to the maritime traffic or accidental pollution. Following the recommendations of the Marine Strategy Framework Directive,...

Marine litter is a widespread problem affecting all the oceans of the world. Plastics represent around 90% of marine litter, and it is estimated that there are between 15 and 51 trillion plastic particles floating on the surface of the oceans. The objectives of this study are to: (i) identify and characterize the main categories of floating items s...

Although several bioacoustics investigations have shed light on the acoustic communication of Mediterranean fish species, the occurrence of fish sounds has never been reported below 40 m depth. This study assessed the occurrence of fish sounds at greater depths by monitoring the soundscape of a Mediterranean submarine canyon (Calvi, France) thanks...

Dynamics of the subsurface (2-3 m) mesozooplankton (i.e., > 200 µm) in the Bay of Calvi (Corsica, France) were explored, combining time series (2004-2016) of 14 zooplankton groups, wind gusts, water temperature, nitrate and chlorophyll-a. Zooplankton data was obtained through image analysis. While contrasted group-specific seasonal patterns were ob...

The pennate diatom Haslea ostrearia is the emblematic and most studied species of the genus Haslea. H. ostrearia is mainly benthic and epiphyte, forming biofilms on sediment and on macroalgae. The cells produce a blue-green water-soluble pigment, the marennine, with allelopathic, antioxidant, antiviral and antibacterial properties, as demonstrated...

Submarine canyons are key structures for ecosystem functioning in the Mediterranean Sea. This study was conducted in the canyon of Calvi (North-West Corsica, France) by using a combination of Static Acoustic Monitoring (SAM) and hydrophone integrated gliders (Seaexplorer, Alseamar). During summer 2016 and 2017, three SAM campaigns (-125 m to -150 m...

Seascape ecology has been widely applied to marine habitats, including seagrass meadows, through various approaches all over the world for the past 30 years. However, these methods mainly study seagrass meadows on a single spatial scale and monitor a single driver of heterogeneity. Additionally, few assess the seascape's structural evolution. This...

Dear all, We are editing a Research Topic in Frontiers in Marine Science on the impacts of marine aquaculture on marine biota. Please read the attached pdf with abstract and visit online our Research Topic homepage : https://www.frontiersin.org/research-topics/8745/marine-aquaculture-impacts-on-marine-biota#overview We are now compiling the list...

The aim of this study was to obtain a better understanding of the exploitation pattern of the European lobster population in a fully representative small-scale fishery of the Mediterranean (Corsica, France) and to collect initial biological information on this species. Data were collected by scientific observers on board net fishing vessels for eig...

Arborescent macro-algae forests covering temperate rocky reefs are a known habitat for juvenile fishes. However, in the Mediterranean, these forests are undergoing severe transformations due to pressures from global change. In our study, juvenile fish assemblages differed between pristine arborescent forests (Cystoseira brachycarpa var. balearica)...

Swordfish (Xiphias gladius L., 1758) is an apex predator, highly migratory meso-pelagic fish widely distributed in the Atlantic Ocean and Mediterranean. As top predators, this fish may be the end reservoir of the bioaccumulation of trace elements in a food chain because they occupy higher trophic levels and are an important food source, causing the...

Pollution and damages produced by boats anchoring over Posidonia oceanica seagrass meadows are assumed to modify the structure and dynamic of the habitat through fragmentation. In fact, heterogeneity of physical structure plays a major role in their ecological functioning. Two sites were studied in this case study: anthropogenic altered seagrass me...

Two indices were developed in Calvi Bay (Corsica, France) to detect and evaluate the impact of anchoring on the meadows formed by the Mediterranean seagrass Posidonia oceanica (L.) Delile. On the one hand, a first index, built to identify area of high anchoring pressure with structural impacts, is based on cartographic analysis. It computes seascap...

Le projet STARECAPMED (STAtion of Reference and rEsearch on Change of local and global Anthropogenic Pressures on Mediterranean Ecosystems Drifts) a pour objectif (i) d'améliorer la compréhension du fonctionnement des différents écosystèmes marins côtiers présents en Méditerranée et (ii) de décrire l'influence des pressions humaines, tant locales q...

Structural boundaries in ecosystems play an important role both in the context of seascape architecture and ecological processes. The Mediterranean seagrass Posidonia oceanica (L.) Delile is considered an ecosystem engineer species, forming habitats of great ecological value and providing many ecosystem services. However so far, only few studies ha...

Passive acoustic recording (PAR) systems are non-invasive and allow researchers to collect data on large spatial and temporal scales. Since fish sounds are species-specific and repetitive, PAR can provide a large amount of data about spatio-temporal variation in fish distribution and behaviors. Ophidion rochei is a sand-dwelling species from Medite...

The spatial dynamics of the Posidonia oceanica meadows is a process extending over centuries. This article shows evidence of the natural dynamics of the P. oceanica “shifting intermattes” or “sand corridors” (hereafter SCs) – unvegetated patches within a dense meadow. We have studied the features and temporal evolution (2001–2015) of five SCs in th...

In Mediterranean subtidal rocky reefs, Cystoseira spp. (Phaeophyceae) form dense canopies up to 1 m high. Such habitats, called 'Cystoseira forests', are regressing across the entire Mediterranean Sea due to multiple anthropogenic stressors, as are other large brown algae forests worldwide. Cystoseira forests are being replaced by structurally less...

List of the macrophytes operational taxonomic units and their functional group. (DOCX)

Supplementary analysis of fish body size distributions across habitats: Methods and Results. (See also S2 Fig) (DOCX)

Fish body-size distributions compared across habitat types and Localities. Curves are smoothed histograms (Kernel density estimations) of total lengths of all sampled fish (crypto- or necto- benthic) within each level of the combined factor habitat X locality-protection (region-time). The surfaces below the curves (the integrals) are proportional t...

Sampling of necto-benthic fish assemblage structure using the UVC methodology ‘9 m² stationary-point snapshot-count’. The 9m² sampling area was the semicircle 2.5 m in radius in front of the diver, without considering the inner part, semicircle 0.7 m in radius. (TIFF)

Geographical coordinates of the 23 sampling sites. Latitude (North) and Longitude (East) are in decimal degrees (See also Fig 2). (DOCX)

Possible mechanisms underlying differences in fish assemblage composition between Cystoseira forest, turfs and barrens. A discussion enriched by previous studies on density patterns and fish life history traits found in the literature. (DOCX)

The Neptune grass Posidonia oceanica forms extensive meadows from the surface to 40 m depth in the Mediterranean Sea, and constitutes a seascape matrix in which natural and anthropogenic patches are generated. Among patch types induced by human activities, those created by mechanical damages (e.g. trawling, anchoring) are known to quickly generate...

Marine magnoliophytes are major primary producers in coastal benthic habitats worldwide. They play a crucial role in the global carbon cycle (one of the more efficient blue carbon wells). Hence, it is necessary to characterise the eco-systemic services seagrass meadows provide. Posidonia oceanica (L.) Delile, the main Mediterranean seagrass species...

Intensive anchoring of leisure boats in seagrass meadows leads to mechanical damages. This anthropogenic impact creates bare mat patches that are not easily recolonized by the plant. Several tools are used to study human impacts on the structure of seagrass meadows but they are not able to assess the indirect and long term implication of mechanical...

The common dentex, Dentex dentex (Linnaeus, 1758), is an iconic coastal fish found in the Mediterranean Sea. Despite its ecological and economic importance, scientific data on its exploitation are scarce, especially off Corisca. The aims of our study were to: (1) analyze the relationship between the catch per unit effort (CPUE, by weight and number...

The Marine and Oceanographic Research Station STARESO in the Calvi Bay, Corsica (France), is a unique tool in a preserved natural site that includes all the characteristic ecosystems of the Mediterranean littoral. The station, established in 1970, has archived environmental data for decades. The STARECAPMED project, multidisciplinary, articulates i...

Sound production by the dusky grouper Epinephelus marginatus was monitored both in captivity and at two Mediterranean spawning sites during the summers of 2012 and 2013. The results of long-term passive acoustic recordings provide for the first time a description of the sounds produced by E. marginatus. Two types of sounds were mainly recorded and...

Rapport (avec la bibliographie) téléchargeable à l'adresse suivante: http://orbi.ulg.ac.be/handle/2268/187710 La prise de conscience, par le grand public, de l'impact grandissant de l'homme sur l'océan est récente. Elle se traduit par une volonté politique sincère de correction par des mesures de protection, de gestion et de développement durable...

The meadows formed by the Mediterranean seagrass Posidonia oceanica are subjected to various natural (e.g., water movement, light availability, sedimentation) and anthropogenic (e.g., anchoring, trawling, fish farms, explosives) phenomena that erode them and create diverse types of patches. The assemblage of the P. oceanica matrix and these patches...

Over the last decades, the interest in mapping Posidonia oceanica beds has increased along with the improvement of the equipment’s precision of data acquisition. In Calvi Bay (Corsica, France) the meadows cover an area of about 5 km² and are found at a depth ranging from 3 m to 37 m. The availability of three distinct datasets for 1997, 2002 and 20...

The meadows formed by the Mediterranean seagrass Posidonia oceanica are subjected to various natural (e.g., water movement, light availability, sedimentation) and anthropogenic (e.g., anchoring, trawling, fish farms, explosives) phenomena that erode them and create diverse types of patches. The assemblage of the P. oceanica matrix and these patches...

Biological indicators have the capacity to integrate the temporal changes of contaminants, concentrations or fluxes over various time-scales, and are thus considered as interesting tools for water quality biomonitoring. Since the mid-70ies, French programs have developed water monitoring approaches based on the use of bivalve molluscs; and recently...

Human activities generate large volumes of waste that supply marine coastal environments in pathogens, organic matter, nutrients and toxicants. Among the wide range of toxicants are trace elements. Since the latter are toxic for aquatic organisms from threshold levels and as they are therefore likely to cause multiple damage to the population, the...

Biological indicators have the capacity to integrate the temporal changes of contaminants, concentrations or fluxes over various time-scales, and are thus considered as interesting tools for water quality biomonitoring. Since the mid-70ies, French programs have developed water monitoring approaches based on the use of bivalve molluscs; and recently...

The seagrass Posidonia oceanica is widely recognized as an effective bioindicator of the health status of Mediterranean coastal waters. Chlorophyll fluorescence measurements, in particular through the Pulse Amplitude Modulated (PAM) fluorometry method, are performed to study aquatic plant ecology and vitality and to assess their responses to divers...

The seagrass Posidonia oceanica is widely recognized as an effective bioindicator of the health status of Mediterranean coastal waters. Chlorophyll fluorescence measurements, in particular through the Pulse Amplitude Modulated (PAM) fluorometry method, are performed to study aquatic plant ecology and vitality and to assess their responses to divers...

Over the last decades, the interest in mapping Posidonia oceanica beds has increased along with the improvement of the equipment’s precision of data acquisition. In Calvi Bay (Corsica, France) the meadows cover an area of about 5 km² and are found at a depth ranging from 3 m to 37 m. The availability of three distinct datasets for 1997, 2002 and 20...

Over the last decades, the interest in mapping Posidonia oceanica beds has increased along with the improvement of the equipment’s precision of data acquisition. In Calvi Bay (Corsica, France) the meadows cover an area of about 5 km² and are found at a depth ranging from 3 m to 37 m. The availability of three distinct datasets for 1997, 2002 and 20...

Effective ecosystem-based management requires understanding ecosystem responses to multiple human threats, rather than focusing on single threats. To understand ecosystem responses to anthropogenic threats holistically, it is necessary to know how threats affect different components within ecosystems and ultimately alter ecosystem functioning. We u...

Islands are subject to human activities and their impacts on land and marine ecosystems. They are also often isolated from some of the continental influences but on the other hand different kind of human activities can be concentrated in small areas. These characteristics make possible the management of many programs that use whole islands, or some...

In Corsica (NW Mediterranean), most of the fishing activity is composed of small-scale artisanal fisheries, and takes place on the western coast. The common spiny lobster (Palinurus elephas) is the main target of Corsican netters. However, its populations have been declining since the 1950's, questioning the sustainability of this activity. We ther...

The Mediterranean seagrass Posidonia oceanica forms meadows and develops a complex of rhizomes, roots and sediment which is called “matte”. P. oceanica meadows show discontinuity patterns in the form of sand or dead matte (matte without living shoots) patches, called “intermattes”, which can have natural or anthropogenic origins. Mechanical process...

Corsica Island is a sub-basin of the Northwestern Mediterranean Sea, with hydrological features typical of both oligotrophic systems and eutrophic coastal zones. Phytoplankton assemblages in two coastal ecosystems of Corsica (the deep Bay of Calvi and the shallow littoral of Bastia) show contrasting patterns over a one-year cycle. In order to deter...

The LIMA index conveys the environmental interest and quality of the landscape formed by the Mediterranean benthos, ranging from 0 to − 40 m, in numerical format. The LIMA index allows a comparison spatially and temporarily between sites. It is a comprehensive index which is easy to implement and is composed of two factors: a topographical descript...

In Mediterranean infralittoral rocky reefs, macroalgal forests formed by Cystoseira species regress as a consequence of anthropogenic stressors, and are usually replaced by less complex assemblages (e.g. shrub-like photophilous seaweeds, coralline barrens). In order to assess the consequences of such a shift, we described the patterns of fish assem...

Sorting of soft-bottom macrobenthos entangled with Posidonia oceanica fibers is time-consuming and tedious because of the weak color contrast. This paper describes a staining-destaining technique that produces good contrast between soft-bottom macrobenthos and Posidonia oceanica fibers. The method has been tested on Corsican samples in oligotrophic...

La STAtion de Recherches Sous-marines et Océanographiques (STARESO) a été choisie pour travailler sur le sous-projet SD du programme MARTE+ qui porte sur les innovations des systèmes productifs et techniques pour la pêche. La composante qui intéresse la STARESO est la composante 3 : «L'innovation dans les systèmes techniques de production et de la...

Sorting of soft-bottom macrobenthos entangled with Posidonia oceanica fibers is time-consuming and tedious because of the weak color contrast. This paper describes a staining-destaining technique that produces good contrast between soft-bottom macrobenthos and Posidonia oceanica fibers. The method has been tested on Corsican samples in oligotrophic...

A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research. This enables the prediction of change and possibly the mitigation of the consequences of anthropogenic impacts. One major aim of the European Cooperation in Science and Technology (COST) Action ES060...

A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research. This enables the prediction of change and possibly the mitigation of the consequences of anthropogenic impacts. One major aim of the European Cooperation in Science and Technology (COST) Action ES060...

Posidonia oceanica (L.) Delile is a protected species, included in the Red list of marine threatened species of the Mediterranean. Because of its sensitivity to disturbance, P. oceanica is used as a bioindicator to define the health status of coastal waters. Monitoring methods generally require to sample plants, followed by measurements on picked s...