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See detailSeasonal characterization of the nutrients state in Oualidia Lagoon (Moroccan Atlantic coast)
Damsiri, Zainab; Natij, L.; Khalil, Karima et al

in Journal of Materials and Environmental Science (2017), 8(1), 67-77

The nutrient cycle in Oualidia lagoon, on the Atlantic Moroccan coast, was studied at both spatial and temporal scales, covering spring and summer conditions. Water samples were collected bimonthly at ... [more ▼]

The nutrient cycle in Oualidia lagoon, on the Atlantic Moroccan coast, was studied at both spatial and temporal scales, covering spring and summer conditions. Water samples were collected bimonthly at high tide from March to August during years 2011 and 2012 at six stations distributed throughout the lagoon. The physico- chemistry (temperature, salinity, dissolved O2) and nutrient enrichment of the lagoon surface water were monitored. The average nutrient concentration of surface water were 14.4 μmol.l-1 and 28.1 μmol.l-1 for NH4+, 20.4 μmol.l-1 and 19.9 μmol.l-1 for PO43- and 3.7 μmol.l-1 and 7.6 μmol.l-1 for NO2- in 2011 and 2012, respectively. Strong seasonal differences of nutrient distribution at the different stations were noticed. Temperature, salinity and dissolved O2 were correlated with nutrient concentrations, all parameters showing low spatial (inter-station) variability. Hydrological conditions exert a major control on the nutrient cycling in the lagoon. Results of this study are important to increase the richness on the scientific knowledge of nutrient dynamics along the Moroccan Atlantic coast, particularly in the semi-enclosed lagoons that are important transitional systems. [less ▲]

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See detailCopper toxicity on coral holobiont photosynthetic processes
Georges, Nadège; Richir, Jonathan ULg; Batigny, Antoine et al

Poster (2016, December 16)

Copper (Cu), an essential micronutrient to organisms, may become toxic when present at too high environmental concentrations. This metal remains an aquatic contaminant of concern, notably because of its ... [more ▼]

Copper (Cu), an essential micronutrient to organisms, may become toxic when present at too high environmental concentrations. This metal remains an aquatic contaminant of concern, notably because of its recent re-use as biocide in metal-based antifouling paints. The aim of this study was to monitor the physiological alterations in a zooxanthellate coral species and its endosymbionts (i.e. the coral holobiont) exposed to increasing Cu concentrations. Nubbins of Seriatopora hystrix were exposed for 8 days in 1 L intermittent respirometers to 5 nominal Cu concentrations: 0-2-5-15-50 ppb. Respirometers were maintained at 25.0±0.2°C with successive open/close cycles of 30 min. A 12/12 hours day-night light regime was applied with constant daylight intensity of 200 μmol photons m-2 s-1. Water renewal rate during the 30 min open cycles was 15 mL.min-1. The photosynthetic performances of coral endosymbionts were assessed daily with a fluorescence imaging system (imaging-PAM). At the end of the 8-days experiment, the maximal photochemical quantum yield (FV/FM) of coral nubbins had decreased by 12% and 38%, respectively, in the 15 ppb and 50 ppb treatments. This decrease was even greater for the effective photochemical quantum yield (ɸPSII) with values dropping by 41% and 54%, respectively. Cu exposure also affected the symbiosis between the coral host and its endosymbionts. Nubbins of the 15 ppb treatment slightly lightened from day 6, whilst nubbins exposed to the 50 ppb treatment lightened from day 3, and started to bleach from day 6. The analysis of nubbins’ primary productivity did not coincide with the above observations, the oxygen production within each respirometer remaining relatively constant during the overall experiment for all treatments. This unexpected observation may be the sign of a compensation mechanism. In conclusion, Cu affected the photosynthetic processes of S. histrix within 8 days from relevant environmental concentrations of 15 ppb. The exposure of corals to toxic chemicals thus has to be considered as an additional stressor to, e.g., ocean acidification or elevated temperature, which may disturb their ecophysiology and lead to bleaching. [less ▲]

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See detailBioaccumulation of trace metals in Mytilus galloprovincialis from the Algerian west coast
Rouabhi, Leila; Rouanne, Hassen Omar; Benkrama, Hadjer et al

Poster (2016, December 16)

Algeria has a 1622 km long coastal strip where a large proportion of the population and the main economic and industrial activities of the country are concentrated. Its coastal fringe therefore suffers ... [more ▼]

Algeria has a 1622 km long coastal strip where a large proportion of the population and the main economic and industrial activities of the country are concentrated. Its coastal fringe therefore suffers from various degradations. In particular, the Bay of Oran is housing industrial, commercial, fishing and recreational activities, where 80 % of domestic and industrial wastewaters are not purified before being discharged into the sea. Thus, the aim of the present work was to evaluate the degree of metallic contamination of coastal waters of western Algeria. Trace metals (Zn, Cu, Ni, Fe and Pb) were measured by atomic absorption spectroscopy in the dry soft tissues (gills and gonads) of the mussel Mytilus galloprovincialis Lamarck, 1819 collected during the four seasons of year 2010 in 2 sites: the highly polluted Oran harbor (S1) and Ain Defla (S2), a site distant enough from Oran and presumed little contaminated. Oran harbor was globally more contaminated than Ain Defla, especially for Fe, Zn and Ni. However, Pb levels were higher at Ain Defla with concentrations up to 3.35 ± 0.25 ppm in the gills. Metal concentrations differed between organs. Fe, Zn and Cu were more accumulated in gills (46.91 ± 1.60 ppm, 25.6 ± 1.07 ppm, 2.68 ± 0.50 ppm, respectively) compared to gonads (29.06 ± 1.07 ppm, 21.76 ± 1.46 ppm ppm, 1.44 ± 0.20 ppm, respectively). Each metal followed a seasonal trend, showing concentration peaks during winter and spring for gills and autumn for gonads. This study demonstrated the need to biomonitor the metallic contamination of Algerian coasts. But such monitoring surveys, relying on organisms, will require consensual sampling and analytical protocols to avoid hazardous conclusions due to tissue speciation and accumulation seasonality. [less ▲]

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See detailExploring a Mediterranean mesozooplankton 13 year time-series.
Fullgrabe, Lovina; Richir, Jonathan ULg; Batigny, Antoine et al

Poster (2016, December 16)

Zooplankton plays diverse crucial roles within the marine ecosystem and can also be used as bio- indicator of climate changes since it is very sensitive to environmental changes. Therefore it is essential ... [more ▼]

Zooplankton plays diverse crucial roles within the marine ecosystem and can also be used as bio- indicator of climate changes since it is very sensitive to environmental changes. Therefore it is essential to consider long-term plankton series. Given the analysis of plankton samples is time- consuming, it requires an effective and rapid analytical method. We have used in this work a supervised learning approach adapted for the semi-automatic classification of digital images of the mesozooplankton of the Bay of Calvi (Corsica, France) by using the Zoo/PhytoImage software. Together with a 11-years long zooplankton time-series, a set of nine environmental variables were monitored in order to identify controlling factors and determine whether the communities were sensitive to global environmental changes. The main components of the mesozooplankton community were characterized by both seasonal and inter-annual variability. Additionally, variation of holoplankton and meroplankton differentiated one from each other. The holoplanktonic community could be split into two subgroups according to its variation in function of the environment: cladocerans and appendicularians, and to a lesser extent, copepods on one hand, and cnidarians, chaetognathes and thaliaceans, on the other hand. Regarding inter-annual variation, one year (2007) showed particularly low production of total zooplankton which was also the case for all the different holoplanktonic taxa. Accounting for that phenomenon were identified some potentially underlying environmental factors. Finally, although water temperature increased significantly over the last years along with the frequency of marine heat wave events, no evident change in the global zooplankton composition was observed yet. [less ▲]

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See detailAssessing edge-effects in Posidonia oceanica seagrass meadows: A multidisciplinary approach
Lapeyra, Jon; Abadie, Arnaud; Lejeune, Pierre et al

Conference (2016, December)

Structural boundaries in ecosystems play an important role both in the context of seascape architecture, ecological processes and biodiversity. The Mediterranean Seagrass Posidonia oceanica (L.) Delile is ... [more ▼]

Structural boundaries in ecosystems play an important role both in the context of seascape architecture, ecological processes and biodiversity. The Mediterranean Seagrass Posidonia oceanica (L.) Delile is considered an ecosystem engineer species, forming habitats of great ecological value and providing many ecosystem services. This study aims to (1) determine whether there are differences between seagrass-sand corridors edges and the adjacent continuous meadow, and (2) investigate whether anthropogenic pressures can cause disturbances in the measured parameters along the edges and the meadow. We have developed a multidisciplinary approach combining plant physiology, faunal canopy community studies and seagrass structural parameters characterization. We performed in situ chlorophyll fluorescence measurements using a Pulse Amplitude Modulated (Diving-PAM) fluorometry in order to assess the photosynthetic rate of the shoots. Vagile macrofauna of the leaf stratum was sampled by a hand-towed net, and the major taxonomic groups were sorted, counted, and identified. Meadow’s biometric measurements and the epiphytic biomass were also determined. Regarding edge-meadow matrix, results have shown highest differences on matrix structural parameters such as shoot density and shoot type proportions. Shoot density was found to decrease in edges considerably. We found c.a to 60 % plagiotropic shoots on edges while in continuous meadow orthotropics were predominant (up to 90 %). Howerver vagile-fauna population densities and diversity did not differ significantly among stations studied, neither by sites. Photosynthetic rate and leaf surface values also did not show changes between edges and continuous meadow. However, results did show that plagiotropic shoots had higher photosynthetic rate than orthotropics, and also that epiphyte abundance sorted out to be much higher (up to 54 %) on edges. [less ▲]

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See detailEcoNum, a research unit devoted to marine environment monitoring
Richir, Jonathan ULg; Batigny, Antoine; Georges, Nadège et al

Conference (2016, October 27)

The monitoring of coastal environments remains a research domain of great interest and concern. Coastal ecosystems are threatened by natural and human-induced stressors and are, as transitional ... [more ▼]

The monitoring of coastal environments remains a research domain of great interest and concern. Coastal ecosystems are threatened by natural and human-induced stressors and are, as transitional environments, particularly sensitive to disturbances. EcoNum first research thematic revolves around hermatypic corals, calcifying organisms, and their adaptation potentials to environmental changes including by using original and patented chemostats. The studied organisms are grown and maintained in artificial mesocosms that simulate environmental conditions of a natural system. This infrastructure allows to perform long-term experiments, giving time to organisms to adapt to the tested conditions (e.g., increased temperature or lowered pH). Longer-term studies have demonstrated that many organisms are more resistant to environmental stressors than previously observed on the short-term. EcoNum also studies coastal plankton abundance and diversity. Plankton is particularly sensitive to physicochemical changes of water bodies. The classification and the enumeration of planktonic organisms require specialized tools in order to analyse time series of multiple samples. EcoNum has developed a software for the semi-automatic classification of planktonic organisms called Zoo/PhytoImage. This software has been used to study a 10-year time series of coastal Mediterranean zooplankton samples. The concomitant analysis of environmental parameters registered at high frequency with specific statistical tools such as the R package pastecs allows to understand the processes governing the changes observed in plankton assemblages. The use and the development of statistical tools in R (e.g., Zoo/Phytoimage, pastecs) is a priority of EcoNum to favour open access knowledge and reproductive sciences. EcoNum research topics also focus on coastal ecotoxicology. Chemicals, including trace elements, remain contaminants of concern, mainly in coastal environments that are the final sink of inland pollution sources. The chemical integrity of coastal ecosystems thus has to be accurately monitored. The partitioning of chemicals between their dissolved, particulate and sedimentary phases does not provide information on their bioavailability. EcoNum thus monitors coastal waters using bioindicator species such as seagrasses, mussels or sand worms. A global map of the contamination of the Mediterranean by trace elements has been drawn using seagrasses has bioindicator species. EcoNum also studies trace element ecology and toxicology. For instance, it has demonstrated the toxicity of copper on the coral Seriatopora hystrix and it's symbiont's photosynthetic processes, or its bioaccumulation and basipetal translocation towards rhizomes in the seagrass Posidonia oceanica as reserve nutrient for subsequent leaf growth. Finally, coastal vegetated systems are potential carbon thinks (or sources) in the global carbon cycle. Therefore, EcoNum studies the primary productivity of seagrass meadows, from the individual to the community, with measuring techniques as diverse as PAM-fluorometry or biomass production determination. To conclude, EcoNum is a research unit devoted to marine environment monitoring. It develops research thematics on major coastal communities such as coral reefs, seagrass beds or plankton assemblages and studies their natural dynamics and the effects of stressors on their global functioning. [less ▲]

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See detailA one year survey of seagrass primary productivity using the diving-PAM technique
Richir, Jonathan ULg; Abadie, Arnaud; Grosjean, Philippe et al

Poster (2016, October 18)

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 ... [more ▼]

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, has high foliar and belowground biomass production. Several methods have been used so far to measure its primary production (e.g., using incubation bells, optodes, biomass and elementary content measurements). A less used method relies on chlorophyll fluorescence measurements through the Pulse Amplitude Modulated (PAM) fluorometry method (Diving - PAM). In the framework of the STARECAPMED project, this study aimed to determine weekly to bimonthly over a one-year period the photosynthetic responses (Yield, relative Electron Transfer Rate, Rapid Light Curve) of P. oceanica. The survey was performed at 10m depth in a pristine meadow (Calvi, Corsica, France). To obtain reliable and comparable data, the protocol was standardized: measurements were performed on the convex middle part of the third leaf, at zenith, during shiny and calm weather days. Results showed that the plant displayed a well-marked seasonality. The mean ETR (μmol e- m-2 s-1 ) of the plant ranged from 2.17 in winter to 21.9 in summer and was linearly correlated throughout the year with the in situ irradiance (PAR irradiance taken perpendicularly to the surface, in the average leaf orientation). The ETR plateaus of the RLCs, ranging from 10.9 to 35.0, and their corresponding maximum PAR intensities evolved similarly. These results demonstrated both the adaptation and the seasonal plasticity of the meadow’s photosynthetic system. Overall the non-destructive PAM technique is a powerful and cost-effective tool to assess the primary productivity of seagrass meadows where other techniques (e.g. optodes) cannot be used and when direct sampling (e.g. biomass measurements) is not allowed. [less ▲]

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See detailInvestigating the potential of Cymodocea nodosa (Ucria) Ascherson as a coastal carbon sink coupling marine habitat cartographies and in situ nondestructive sampling
Abadie, Arnaud ULg; Richir, Jonathan ULg; Pieraccini, Riccardo ULg et al

Poster (2016, October)

Seagrass meadows are major carbon sinks, trapping about 10% of the total CO2 sequestrated in the oceans. In the Mediterranean, a major focus has been made on the climax species Posidonia oceanica (L ... [more ▼]

Seagrass meadows are major carbon sinks, trapping about 10% of the total CO2 sequestrated in the oceans. In the Mediterranean, a major focus has been made on the climax species Posidonia oceanica (L.) Delile, while other species remained little studied. In the framework of the STARECAPMED project, we thus chose to study Cymodocea nodosa (Ucria) Ascherson, a pioneer species with a rapid turnover and an expected high stocking capacity. Furthermore, the area covered by that species has been largely underestimated. In order to fill these two knowledge gaps, we first mapped all seagrass habitats within a Mediterranean bay (Calvi, Corsica, France) using side scan images, aerial photographs and ground truths. This cartography was followed by seasonal in situ density measurements and non-destructive shoot sampling (leaf cutting). Samplings were performed at different depths (5 to 23 m depth) in 6 contrasted stations (small patchy meadows to continuous beds) in order to cover all the existing facies of the bay. Elementary contents (carbon, nitrogen and stable isotope ratios) were measured in laboratory. This first work shows that C. nodosa meadows in Calvi Bay cover an area of 0.498 km2. Carbon stocks of the leaves reached 0.25 tons in winter and 2.72 tons in summer. Their nitrogen contents showed a marked seasonality with a maximum value of 0.020 mgN.m-2 in July and a minimum value of 0.005 mgN.m-2 in March. Some modifications in the trophic conditions of the water column at several stations were put in an obvious through the N stable isotopes values, mostly during the summer period. The actual underestimation of the area covered by that species in Calvi Bay has been properly mapped thanks to side scan sonar techniques revealing, together with elementary content analysis, its importance in the carbon balance of coastal areas. [less ▲]

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See detailModelling nitrogen incorporation by primary producers of a Mediterranean coastal area
Elkalay, Khalid; Frangoulis, Constantin; Richir, Jonathan ULg et al

Conference (2016, May 11)

The aim of this study was to simulate the uptake flow of nitrogen (gN m-2) of P. oceanica meadow for 4 primary producers of the bay of Calvi (Corsica, France) (phytoplankton, macro-algae, the Posidonia ... [more ▼]

The aim of this study was to simulate the uptake flow of nitrogen (gN m-2) of P. oceanica meadow for 4 primary producers of the bay of Calvi (Corsica, France) (phytoplankton, macro-algae, the Posidonia oceanica leaves and their epiphytes). The model developed for this purpose simulates the evolution of nitrogen incorporation. The effect of the light intensity, and the water column temperature and concentration in internal and external nitrogen on nitrogen incorporation by the 4 primary producers is modeled. Thus, the incorporation rate of both NO3-and NH4+by phytoplankton was more important than for benthic producers. Macro-algae incorporations had intermediate incorporation rates between the ones of, the phytoplankton and P. oceanic leaves and their epiphytes. The incorporation of NH4+ by the phytoplankton is higher than the incorporation of NO3-. The model appears well adapted to establish the main environmental factors that determine the incorporation of inorganic nitrogen by the various primary producers. It is also able to represent the relative importance of nitrogen incorporation by the various producers. [less ▲]

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See detailEnvironmental monitoring: between science and decision-making
Richir, Jonathan ULg; Gobert, Sylvie ULg; Lejeune, Pierre et al

Scientific conference (2016, April 13)

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See detailEstimating carbon fluxes in a Posidonia oceanica system: Paradox of the bacterial carbon demand
Velimirov, Branko; Lejeune, Pierre; Kirschner, A. et al

in Estuarine Coastal & Shelf Science (2016), 171

A mass balance ecosystemic approach, based on bacterial carbon demands and primary production data, was used to investigate if the bacterial community (freewater bacterioplankton and benthic bacteria of ... [more ▼]

A mass balance ecosystemic approach, based on bacterial carbon demands and primary production data, was used to investigate if the bacterial community (freewater bacterioplankton and benthic bacteria of the oxygenated sediment layer) could be sustained by the main primary producers (Posidonia oceanica and its epiphytes, adjacent macroalgae and phytoplankton communities; hereafter called the P. oceanica system) of a non-eutrophic Mediterranean bay. Unexpectedly, the findings of this study differed from previous works that used benthic incubation chamber and O2 optode methods. In this study, data were grouped in two categories, corresponding to two time periods, according to the seawater temperature regime (<18 °C or >18 °C): from May to October and from November to April. Between May and October, the produced benthic macrophyte tissues could not provide the carbon required by the bacteria of the oxygenated sediment layer, showing that the balance production of the investigated bay was clearly heterotrophic (i.e. negative) during this time period. In contrast, between November and April, benthic bacteria respiration nearly equated to carbon production. When integrating the open water carbon dynamics above the meadow in the model, a negative carbon balance was still observed between May and October, while a slight carbon excess was noticed between November and April. In the light of these findings, the carbon balance being negative on an annual basis, alternative carbon sources are required for the maintenance of the bacterial carbon production. [less ▲]

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See detailEffets anthropiques sur les écosystèmes marins
Richir, Jonathan ULg; Grosjean, Philippe

Scientific conference (2016, January 28)

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See detailTrace metals in soft tissue of marine bivalve Noah's ark (Arca noao) from Bizerte lagoon (Northern Tunisia)
Ghribi, Feriel; Richir, Jonathan ULg; Boussafa, Dhouha et al

in Rapports et Procès Verbaux des Réunions - Commission Internationale pour l'Exploration Scientifique de la Mer Mediterranée (2016), 41

This study aimed to monitor the bioaccumulation of 5 trace elements (TEs: Zn, Fe, Cu, Cd, and Pb) in the soft tissue of the Ark shell (Arca noae), seasonally sampled in Bizerte lagoon, northern Tunisia ... [more ▼]

This study aimed to monitor the bioaccumulation of 5 trace elements (TEs: Zn, Fe, Cu, Cd, and Pb) in the soft tissue of the Ark shell (Arca noae), seasonally sampled in Bizerte lagoon, northern Tunisia, in order to assess the nutritional quality of this bivalve and to promote its consumption as marine resource in Tunisia. The levels of all trace metals analyzed in Arca noae are below maximum admissible level which makes this species a healthy and safe food for human consumption. [less ▲]

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See detailTemporal evolution of sand corridors in a Posidonia oceanica seascape: a 15-years study
Gobert, Sylvie ULg; Lepoint, Gilles ULg; Pelaprat, Corinne et al

in Mediterranean Marine Science (2016), 17(3), 777-784

The spatial dynamic of Posidonia oceanica meadows is a process extending over centuries. This paper shows evidence of the natural dynamics of P. oceanica “shifting intermattes” or “sand corridors” ... [more ▼]

The spatial dynamic of Posidonia oceanica meadows is a process extending over centuries. This paper shows evidence of the natural dynamics of P. oceanica “shifting intermattes” or “sand corridors” (hereafter SCs): unvegetated patches within a dense meadow. We studied features and temporal evolution (2001-2015) of 5 SCs in the Calvi Bay (Corsica) at 15 m depth and followed the characteristics the P. oceanica meadow lining the edge of patches. All SCs show a similar morphology. The eroded side is a vertical edge where roots, rhizomes and sediments are visible, when on the opposite colonized side, the sand is at the same level as the continuous meadow. The vertical edge reaches a maximum height of 160 cm and is eroded by orbital bottom currents with a maximum speed of 12 cm.s-1, the erosion speed ranging from 0.6 to 15 cm.y-1. SCs progress toward the coastline with a mean speed of 10 cm.y-1, the rate of colonization by P. oceanica shoots ranging from 1.5 to 21 cm.y-1. We calculated that the studied SCs would reach the coastline within 500 to 600 years. We finally discuss the implication of such dynamic in the framework of meadows’ colonization assessment and the seascape dynamic. [less ▲]

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See detailTrace Elements in Marine Environments : Occurrence, Threats and Monitoring with Special Focus on the Costal Mediterranean
Richir, Jonathan ULg; Gobert, Sylvie ULg

in Journal of Environmental and Analytical Toxicology (2016), 6:1

Trace elements, as building blocks of matter, are naturally present in the environment. However, their extraction, production, use and release by men can lead to the increase of their environmental levels ... [more ▼]

Trace elements, as building blocks of matter, are naturally present in the environment. However, their extraction, production, use and release by men can lead to the increase of their environmental levels to concentrations that may be toxic for both men and the biota. The overall aim of this review is therefore to recall that trace elements remain contaminants of concern that still require scientific attention. Because marine coastal systems (and transitional environments in general) are particularly vulnerable to contamination processes, they deserve to be accurately monitored with quality indicator species. As an example, the 2 most widely quality indicator species used to assess the health status of the coastal Mediterranean are the seagrass Posidonia oceanica and the mussel Mytilus galloprovincialis. In this review, after a short introduction on human pressures on the World Ocean and the coastal Mediterranean in particular (1), we will redefine the term trace element from an environmental perspective and discuss their accumulation and toxicity for men and the biota (2). We will consider the benefits of using biological indicators instead of water and sediment measurements to assess the health status of the marine environment (3), and more particularly as regards the accurate and complementary indicators that are seagrasses (4) and mussels (5). [less ▲]

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See detailAn ecophysiological discussion of trace element bioaccumulation in cultured Mytilus galloprovincialis
Richir, Jonathan ULg; Gobert, Sylvie ULg

in Belgian Journal of Zoology (2016), 145(1), 53-61

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See detailSTAtion of Reference and rEsearch on Change of local and global Anthropogenic Pressures on Mediterranean Ecosystems Drifts: The STARECAPMED project
Richir, Jonathan ULg; Abadie, Arnaud ULg; Binard, Marc ULg et al

Conference (2015, November 08)

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 ... [more ▼]

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 itself around these two main features. Its objective is to understand how human activities can interact with the fundamental processes that govern the functioning of the different coastal ecosystems of a Mediterranean bay. The understanding of these interactions involves: (i) the identification of the anthropogenic pressures; (ii) the quantification of their impacts on the ecosystems; (iii) the prioritization of these impacts. STARECAPMED also aims to confirm the relevance of the use of the Calvi Bay as a reference in the study of local and global pressures and the changes they may cause on the structure and the functioning of Mediterranean coastal ecosytems. [less ▲]

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See detailThe spatial variability of trace element bioaccumulation processes: Tools to environmental management
Richir, Jonathan ULg; Lejeune, Lejeune; Lepoint, Gilles ULg et al

Conference (2015, November 07)

As transitional environments, coastal meadows are particularly vulnerable to pollution. Trace elements remain contaminants of concern because of their persistence, their ability to accumulate in biota and ... [more ▼]

As transitional environments, coastal meadows are particularly vulnerable to pollution. Trace elements remain contaminants of concern because of their persistence, their ability to accumulate in biota and their toxicity. Local, regional, national and cross-border programs are thus initiated to monitor their environmental occurrence. Sentinel organisms, or bioindicators, have been widely used to this end since they accumulate the bioavailable and thus potentially toxic fraction of contaminants. In the framework of the STARECAPMED project, the accumulation of trace elements in the seagrass Posidonia oceanica (L.) Delile was studied at different spatial scales: along a radial (100 m scale), in a bay (1 km scale), along the French Mediterranean littoral (10-100 km scale) and along the whole Mediterranean coastline (100-1000 km scale). Results showed that the contamination of the sampled shoots could vary as much at opposite scales. This benthic primary producer accumulates contaminants sequestered in the sediments, in addition to their dissolved fraction in the water column. The sediments also offer a time integration of coastal pollution and thus amplify the pollution signal recorded by the seagrass, resulting in the observed spatial variability. These results demonstrate that the in-depth knowledge of the ecology of the monitored bioindicator and the interactions it shares with its environment cannot be ignored. Such failure could lead to erroneous interpretations of the levels of contamination of monitored sites, and points out the need to define a sampling strategy based on the monitoring objectives and the selected bioindicator. [less ▲]

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See detailThe trace element contamination of coastal waters: A holistic approach to environmental monitoring surveys
Richir, Jonathan ULg; Gobert, Sylvie ULg

Conference (2015, November 07)

Sustained monitoring programs are necessary to evidence the efficacy of regulatory controls on pollutant discharges and to assess the health status of ecosystems. Within this perspective, this study aimed ... [more ▼]

Sustained monitoring programs are necessary to evidence the efficacy of regulatory controls on pollutant discharges and to assess the health status of ecosystems. Within this perspective, this study aimed to monitor the coastal trace element contamination of the whole Mediterranean, using Posidonia oceanica (L.) Delile as bioindicator. But sustainable coastal management also requires the development of appropriate classification systems intended, among other purposes, for environmental managers and policy makers. The combined utilization of several complementary monitoring tools - water quality scale, pollution index, spatial analysis - successfully led to the development of such an operational classification system: it allowed to assess contamination threats and to depict contamination gradients of the entire Mediterranean, while assessing more regional and local impacts. Consequently, such holistic approaches should be privileged to accurately monitor the contamination rate of coastal waters and to transfer relevant information on this composite problem to environmental managers and policy makers. [less ▲]

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See detailDGTs, a complementary tool towards more efficient biomonitoring practices
Richir, Jonathan ULg; Lepoint, Gilles ULg; Donnay, Annick et al

Conference (2015, October 01)

Among the diversity of contaminants, trace elements (TEs) remain of concern because of their persistence, their ability to accumulate in biota and their toxicity. The direct measurement of their dissolved ... [more ▼]

Among the diversity of contaminants, trace elements (TEs) remain of concern because of their persistence, their ability to accumulate in biota and their toxicity. The direct measurement of their dissolved concentrations only gives punctual and fluctuating information, and often remains below detection limits of analytical methods. The more appropriate use of sentinel organisms, or bioindicators, to monitor TEs has thus often been preferred in environmental surveys. The introduction of the diffusive gradients in thin films (DGTs) technique has however participated to progressively change this binary view - bioindicator vs water - of the coastal monitoring of TEs, and DGTs rapidly became a relevant complementary tool to bioindicators, has illustrated below. In the framework of the STARECAPMED project, the ecology and the ecotoxicology of TEs were studied in the seagrass Posidonia oceanica (L.) Delile and the mussel Mytilus galloprovincialis Lamarck, 1819. DGTs (free- and pore-water probes) were deployed before sampling of organisms. TEs were also analyzed in suspended matter (dissolved and suspended-particulate TE speciation). Studies were performed in the Calvi Bay (Corsica, France), northwestern Mediterranean. TE concentrations in organisms and suspended matter or in DGT resins were measured by DRC-ICP-MS after HNO3/H202 mineralization or after a 24h elution in HNO3 1M, respectively. (1) TE bioaccumulation was first seasonally studied in P. oceanica over 3 years. Dissolved TE concentrations monitored with DGTs were low to very low. TE bioaccumulation dynamics in P. oceanica could thus be linked to the natural physiological cycle of the plant, in clean environmental conditions. (2) To complement that field survey, isolated seagrasses were in situ contaminated with TEs at environmental relevant concentrations. Through the use of DGTs, TE uptake kinetics were modelled for seagrasses exposed to know bioavailable concentrations of contaminants, as were loss kinetics during the following depuration phase. The TE sequestration ability of a healthy P. oceanica meadow facing sudden trace metal contamination events could also be quantified. (3) The deployment of pore-water DGT probes in bare-sand or seagrass colonized sediments further showed that, through its stabilizing function of the seabed, P. oceanica maintained higher TE levels in the pore-water. P. oceanica meadows thus offer a significant “depuration-filtering” ecological service along highly anthropized Mediterranean coasts. M. galloprovincialis are widely used in large spatial scale coastal monitoring surveys. (4) The deployment of caged mussels together with DGTs showed that the little contaminated water body of the Calvi Bay was relatively homogenous. It also allowed to calculate TE bioaccumulation towards mussels in reference conditions, and to compare it to native mussel populations. (5) Finally, during a 5 months mussel caging survey, mussels and suspended matter were collected weekly to monthly, such as were deployed DGTs. The physiological status of mussels, the speciation of TEs between their dissolved and suspended-particulate phases, and their relative influence on TE bioaccumulation dynamics in mussels were investigated. In conclusion, these case studies properly demonstrate how DGT probes can be used as a relevant and complementary tool to bioindicators. Their concomitant use should therefore be privileged in monitoring surveys. [less ▲]

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