Long-term immersion of compostable plastics in marine aquarium: Microbial biofilm evolution and polymer degradation.

The best-selling compostable plastics, polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT), can accidentally end up in the marine environment due to plastic waste mismanagement. Their degradation and colonization by microbial communities are poorly documented in marine conditions. To better understand their degradation, as well as the dynamics of bacterial colonization after a long immersion time (99, 160, and 260 days), PBAT, semicrystalline, and amorphous PLA films were immersed in a marine aquarium. Sequencing and chemical analyses were used in parallel to characterize these samples. Despite the variation in the chemical intrinsic parameters of these plastics, their degradation remains very slow. Microbial community structure varied according to the immersion time with a high proportion of Archaea. Moreover, the plastisphere structure of PBAT was specific. A better understanding of compostable plastic degradability is crucial to evaluate their impact on ecosystems and to eco-design new recyclable plastics with optimal degradation properties.

Active and passive biomonitoring of trace elements, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in small Mediterranean harbours.

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 species, habitats, and ecosystem services. The monitoring of these compounds is thus a crucial issue for assessment of environmental health. In this context, the aim of the present work was to evaluate the chemical contamination of harbours in Corsica (NW Mediterranean) by measuring the bioaccumulation of trace elements, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in mussels, limpets, and sea cucumbers. The human health risks associated with seafood consumption were also assessed. Results reveal a relatively low contamination in the Corsican harbours studied compared to larger Mediterranean ports and suggest that the potential health risk for consumers eating seafood is low.

A multi-approach inventory of the blue carbon stocks of Posidonia oceanica seagrass meadows: Large scale application in Calvi Bay (Corsica, NW Mediterranean).

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 organic (Corg) and inorganic (Cinorg) carbon stocks in the P. oceanica matte of the Calvi Bay (Corsica) using sub-bottom profiler imagery and biogeochemical analysis of sediment cores. The matte thicknesses map (average ± SD: 2.2 m ± 0.4 m) coupled with marine benthic habitat cartography allows to estimate matte volume at 12 473 352 m3. The cumulative stocks were assessed at 20.2-50.3 kg Corg m-2 and 26.6-58.7 kg Cinorg m-2 within the first meter of depth on matte (3632 ± 486 cal yr BP). The data contributed to estimate the overall carbon stocks at 389 994 t Corg and 615 558 t Cinorg, offering a new insight of the heterogeneity of blue carbon stocks in seagrass meadows. Variability of carbon storage capacity of matte influenced by substrate is discussed.

Ecological and human health risk assessment of potentially toxic element contamination in waters of a former asbestos mine (Canari, Mediterranean Sea): implications for management.

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 the perimeter of the Cap Corse and Agriate Marine Natural Park. The results and multivariate statistical analyses of the potentially toxic elements, made it possible to identify a concentration gradient, a model of bioaccumulation, and the occurrence of different groups, thus reflecting a spatial variation of the contamination. These results indicate that the former asbestos mine can still be considered, 55 years after its closure, as a major source of Co, Cr, and Ni for marine ecosystems and still influences the quality of the coastal area today. Our study, therefore, indicates that the two most polluted sites (Albo and Negru) are the closest stations to the south of the old Canary asbestos mine. According to the Trace Elements Pollution Index (TEPI) values, 6 species were classified as having a high contamination level: Scorpaena notata (1.37), Scorpaena porcus (1.36), Sepia officinalis (1.27), Diplodus vulgaris (1.02), Spicara maena (0.95), and Mullus surmuletus (0.94). Regarding the potentially toxic elements measured in the edible tissues of fish, the concentrations were all below the regulatory thresholds and did not reveal any potential risk to human health (Cd, Cu, Fe, Pb, Se, Sn, Zn). This work provides new and useful information to improve the monitoring of the environmental quality of a region characterized by previous mining activity and to assess the potential risk to human health due to the consumption of fish. Beyond the purely scientific aspects, these results could serve as decision support at the regional level for the definition of long-term public policies.

Effect of land use on microplastic pollution in a major boundary waterway: The Arvand River.

The occurrence of microplastics (MPs) was investigated in the Arvand River (Iran). The Arvand River (200 Km) is a major water body that flows through land with diverse use and it meets the Persian Gulf. This study constitutes the first assessment of MP pollution (prevalence and physico-chemical characteristics) in the Arvand river, both in the sediment and in the water. MP monitoring has been carried out in 24 stations located along the river. The MP pollution found ranged between 1 and 291 items·L-1 and 70 to 15,620 items·kg-1 (dw), in water and sediment, respectively. The majority of MPs were fibres, black/grey and yellow/orange in colour, and mainly 250-500 µm and >1000 µm in size. Polyethylene terephthalate (PET), polypropylene (PP), nylon (NYL), high-density polyethylene (HDPE), and polystyrene (PS) were found in sediment samples. All these polymers, except HDPE, were also identified in the water samples. PET and PP were dominant in the water samples; whereas PET and PS were the most abundant in the sediments. The vicinity of urban wastewater effluents could be behind MP pollution in both water and sediments. Significant differences (p < 0.05) of MP concentrations were affected by different land uses when comparing MP levels in undisturbed natural area with urban areas. A strong correlation between MP fibres and fragments found with PCA biplots revealed their similar distribution in water. In the sediment samples, fibre and fragment MP particles were significantly correlated with colloidal particles (e.g., clay and organic matter) suggesting a relevant role of colloidal particles in the aquatic ecosystem of the Arvand River in transporting MPs. This study contributes to the better understanding of the presence of MP in major rivers, which are systems that have been scarcely investigated for this type of pollution, and it can inform interventions to reduce MP inputs to the river and sea.

Distribution of macroalgae in the area of Calvi (Corsica).

BACKGROUND: 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 describes the dataset generated in the framework of the evaluation of the potential of a complementary data acquisition method: annotating videos transects obtained using an underwater Remotely Operated Vehicle (ROV).The focus was on Cystoseirabrachycarpa, together with the abundance of several other macroalgae species, which could be identified using the ROV images after validation through specimen identification. Furthermore, in order to allow future uses, such as monitoring the status of colonisation of the invasive algae Caulerpacylindracea, the ROV was sent to some deeper transects on sedimentary habitats (40 m) below the Posidonia meadows lower limits. NEW INFORMATION: The project, while providing some interesting insights on using a ROV as a tool to study marine biodiversity, generated a dataset for the distribution of 19 macroalgae on both standardised and new transects in the Bay of Calvi (Katz et al. 2021). The observed species of macroalgae included: Acetabulariaacetabulum, Amphiroarigida, Caulerpaprolifera, Caulerpacylindracea, Codiumbursa, Colpomeniasinuosa, Corallinales (order), Cystoseirabrachycarpa, Cystoseiracrinita, Cystoseiraspinosa, Cystoseirazosteroides, Dictyota (genus), Flabelliapetiolata, Halopteris (genus), Halopterisscoparia, Jania (genus), Osmundariavolubilis, Padina pavonica and Peyssonneliasquamaria.The videos also showed that the invasive algae Caulerpacylindracea has spread between 2016 and 2019 and that more focused studies should be held in the Bay to assess the actual reach and possible impacts of this invasion.Finally, our ROV video transects have also underlined the significant presence of particular benthic macroalgae communities over habitat zones described as "soft-bottom" on benthic habitat maps. Although the biomass per unit area of these communities is probably lower than for most coastal rocky bottoms, this widely-spread habitat type holds a contribution to primary production to be considered in coastal ecosystem models.

Transcriptional regulation of ZIP genes is independent of local zinc status in Brachypodium shoots upon zinc deficiency and resupply.

The biological processes underlying zinc homeostasis are targets for genetic improvement of crops to counter human malnutrition. Detailed phenotyping, ionomic, RNA-Seq analyses and flux measurements with 67 Zn isotope revealed whole-plant molecular events underlying zinc homeostasis upon varying zinc supply and during zinc resupply to starved Brachypodium distachyon (Brachypodium) plants. Although both zinc deficiency and excess hindered Brachypodium growth, accumulation of biomass and micronutrients into roots and shoots differed depending on zinc supply. The zinc resupply dynamics involved 1,893 zinc-responsive genes. Multiple zinc-regulated transporter and iron-regulated transporter (IRT)-like protein (ZIP) transporter genes and dozens of other genes were rapidly and transiently down-regulated in early stages of zinc resupply, suggesting a transient zinc shock, sensed locally in roots. Notably, genes with identical regulation were observed in shoots without zinc accumulation, pointing to root-to-shoot signals mediating whole-plant responses to zinc resupply. Molecular events uncovered in the grass model Brachypodium are useful for the improvement of staple monocots.

Microbial biofilm composition and polymer degradation of compostable and non-compostable plastics immersed in the marine environment.

Different plastic types considered as compostable are found on the market such as petro-based (e.g., polybutylene adipate terephthalate (PBAT)) or bio-based plastics (e.g., polylactic acid, (PLA)). Even if their degradation has been confirmed in industrial compost conditions, investigation of their degradation in natural marine environment has been limited. To better understand biodegradation into natural marine environment, commercial compostable (PBAT, semi-crystalline and amorphous PLA) and non-compostable polymers (low density polyethylene, polystyrene, polyethylene terephthalate, polyvinyl chloride) were submerged in situ on the sediment and in the water column in the Mediterranean Sea. These samples were studied by chemical and microbiological approaches. After 82 days of immersion, no significant bacterial degradation of the different polymers was observed, except some abiotic alterations of PBAT and LDPE probably due to a photooxidation process. However, after 80 days in an enrichment culture containing plastic films as a main carbon source, Marinomonas genus was specifically selected on the PBAT and a weight loss of 12% was highlighted. A better understanding of the bacterial community colonizing these plastics is essential for an eco-design of new biodegradable polymers to allow a rapid degradation in aquatic environment.

Zooplankton dynamics in a changing environment: A 13-year survey in the northwestern Mediterranean Sea.

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 observed, the most productive zooplankton annual event occurred in April (spring peak), concentrating on average 25% of the total annual abundance. A "typical" year was defined based on the annual succession of different community states, highlighting particular years (2007, 2015 and 2012) mainly characterized by weak spring peak. Environmental influences on the interannual variability of zooplankton were explored and while relationship between chlorophyll-a and zooplankton abundance was unclear, the availability of nutrients (December-March), potentially mediated via the wind regime (October-January) seemed to be essential to the occurrence of the spring peak. Additionally, we observed an influence of temperature, with winter thermal thresholds (between 12.1 °C and 13.4 °C) conditioning the spring peak. Also, the occurrence of lower annual abundances after 2010 was synchronous with the sharp increase of seawater warming trend, especially regarding winter temperature (0.30 °C.year-1). Finally, winter North Atlantic Oscillation (NAO) was found to be correlated to both winter water temperature and spring peak abundance, which suggests large-scale processes to impact regional zooplankton community.

Trace elements and oxidative stress in the Ark shell Arca noae from a Mediterranean coastal lagoon (Bizerte lagoon, Tunisia): are there health risks associated with their consumption?

The current study examined the concentrations of ten trace elements (TE) (nickel, chromium, cadmium, iron, zinc, manganese, aluminum, copper, selenium and lead) in the edible tissue of the Ark shell Arca noae (L. 1758) from a Mediterranean coastal lagoon, the Bizerte lagoon during 2013-2014. The analysis of several redox status biomarkers, metallothioneins (MTs), malondialdehyde (MDA), glutathione peroxidase (GPx), reduced glutathione (GSH) and acetylcholinesterase (AChE), was monitored as a response to TE bioaccumulation and environmental parameters variability. Significant differences (p < 0.05) were observed between mean seasonal TE concentrations in A. noae soft tissue. The highest TE concentrations in A. noae soft tissues were recorded during summer, which coincided with the increase of body dry weight (BDW) and the gonad index (GI). During this season, biomarker responses were enhanced, revealing significant increases of MTs, MDA and GSH levels as well as GPx activity in A. noae tissues, while a decrease of AChE activity was observed. The levels of TE analyzed in A. noae and several parameters used to assess the potential human risk (estimated weekly intake, target hazard quotient and target hazard risk) were lower than the permissible limits for safe seafood consumption. Consequently, this shellfish can be considered safe for human consumption. This preliminary study presents prospects for the valorization of this seafood product in Tunisia's food sector. It also gives basal information for future environmental assessment studies in which A. noae could be used as early warning tools in the field of biomonitoring programs and confirms the usefulness of biomarkers to monitor the health status of aquatic organisms.

Trace Elements and Fatty Acid Profile of Argyrosomus regius (Asso, 1801) from Mediterranean Aquaculture.

Although Argyrosomus regius (Asso, 1801) counts among the most appreciated and increasingly consumed fish species in Europe, little information is available on its flesh quality. This research concerns both healthy aquatic resource diversification and good nutritional quality. It is the first study to evaluate the quality of A. regius flesh from Mediterranean aquaculture. It aims to assess the concentration of 19 trace elements and to determine the fatty acid profile of this fish farmed in the Mediterranean Sea and to discuss human exposure risks. The nutritional intake of oligoelements (selenium (Se), zinc (Zn), and chromium (Cr)) and the mean concentrations of contaminants (arsenic (As), barium (Ba), cadmium (Cd), lead (Pb), and tin (Sn)) in A. regius muscles are, respectively, above and below recommended regulatory standards set by the international legislation. Additionally, the low fat content in its muscle mass and its high level of docosahexaenoic acid (C22: 6 n-3; DHA) and, to a lesser extent, eicosapentaenoic acid (C20: 5 n-3; EPA) confers satisfying nutritional qualities. This study allowed to conclude that meager can be considered as a source of seafood with good nutritional qualities for human health.

The plastisphere in marine ecosystem hosts potential specific microbial degraders including Alcanivorax borkumensis as a key player for the low-density polyethylene degradation.

Most plastics are released to the environment in landfills and around 32% end up in the sea, inducing large ecological and health impacts. The plastics constitute a physical substrate and potential carbon source for microorganisms. The present study compares the structures of bacterial communities from floating plastics, sediment-associated plastics and sediments from the Mediterranean Sea. The 16S rRNA microbiome profiles of surface and sediment plastic-associated microbial biofilms from the same geographic location differ significantly, with the omnipresence of Bacteroidetes and Gammaproteobacteria. Our research confirmed that plastisphere hosts microbial communities were environmental distinct niche. In parallel, this study used environmental samples to investigate the enrichment of potential plastic-degrading bacteria with Low Density PolyEthylene (LDPE), PolyEthylene Terephthalate (PET) and PolyStyrene (PS) plastics as the sole carbon source. In this context, we showed that the bacterial community composition is clearly plastic nature dependent. Hydrocarbon-degrading bacteria such as Alcanivorax, Marinobacter and Arenibacter genera are enriched with LDPE and PET, implying that these bacteria are potential players in plastic degradation. Finally, our data showed for the first time the ability of Alcanivorax borkumensis to form thick biofilms specifically on LDPE and to degrade this petroleum-based plastic.

Sea chordophones make the mysterious /Kwa/ sound: identification of the emitter of the dominant fish sound in Mediterranean seagrass meadows.

The /Kwa/ vocalization dominates the soundscape of Posidonia oceanica meadows but the identity of the species emitting this peculiar fish sound remains a mystery. Information from sounds recorded in the wild indicates that the emitting candidates should be abundant, nocturnal and benthic. Scorpaena spp. combine all these characteristics. This study used an interdisciplinary approach to investigate the vocal abilities of Scorpaena spp.; morphological, histological and electrophysiological examinations were interpreted together with visual and acoustic recordings conducted in semi-natural conditions. All observed Scorpaena spp. (S. porcus, S. scrofa and S. notata) share the same sonic apparatus at the level of the abdominal region. This apparatus, present in both males and females, consists of 3 bilaterally symmetrical muscular bundles, having 3-5 long tendons, which insert on ventral bony apophyses of the vertebral bodies. In all chordophones (stringed instruments), the frequency of the vibration is dependent on the string properties and not on the rate at which the strings are plucked. Similarly, we suggest that each of the 3-5 tendons found in the sonic mechanism of Scorpaena spp. acts as a frequency multiplier of the muscular bundle contractions, where the resonant properties of the tendons determine the peak frequency of the /Kwa/, its frequency spectra and pseudo-harmonic profile. The variability in the length and number of tendons found between and within species could explain the high variability of /Kwa/ acoustic features recorded in the wild. Finally, acoustic and behavioural experiments confirmed that Scorpaena spp. can emit the /Kwa/ sound.

Harmful or harmless: Biological effects of marennine on marine organisms.

Marennine is a water-soluble blue-green pigment produced by the marine diatom Haslea ostrearia. The diatom and its pigment are well known from oyster farming areas as the source of the greening of oyster gills, a natural process increasing their market value in Western France. Blooms of blue Haslea are also present outside oyster ponds and hence marine organisms can be exposed, periodically and locally, to significant amounts of marennine in natural environments. Due to its demonstrated antibacterial activities against marine pathogenic bacteria (e.g. Vibrio) and possible prophylactic effects toward bivalve larvae, marennine is of special interest for the aquaculture industry, especially bivalve hatcheries. The present study aimed to provide new insights into the effects of marennine on a large spectrum of marine organisms belonging to different phyla, including species of aquaculture interest and organisms frequently employed in standardised ecotoxicological assays. Different active solutions containing marennine were tested: partially purified Extracellular Marennine (EMn), and concentrated solutions of marennine present in H. ostrearia culture supernatant; the Blue Water (BW) and a new process called Concentrated Supernatant (CS). Biological effects were meanwhile demonstrated in invertebrate species for the three marennine-based solutions at the highest concentrations tested (e.g., decrease of fertilization success, delay of embryonic developmental stages or larval mortality). Exposure to low concentrations did not impact larval survival or development and even tended to enhance larval physiological state. Furthermore, no effects of marennine were observed on the fish gill cell line tested. Marennine could be viewed as a Jekyll and Hyde molecule, which possibly affects the earliest stages of development of some organisms but with no direct impacts on adults. Our results emphasize the need to determine dosages that optimize beneficial effects and critical concentrations not to be exceeded before considering the use of marennine in bivalve or fish hatcheries.

Comparison of elemental composition in two wild and cultured marine fish and potential risks to human health.

Among all available species, fish are a powerful model for risk-benefit assessments to study the effects of contaminants on human health. Gilthead seabream (Sparus aurata, Linnaeus 1758) and european seabass (Dicentrarchus labrax, Linnaeus 1758) are two species of great economic importance, representing very large production volumes in the Mediterranean. The objective of this study is (1) to analyze the concentrations of Trace Elements (TE) between wild and cultured seabream and seabass specimens, (2) to compare the determined concentrations with other studies, and (3) to increase the data about the potential risks to human health. Our results point to significant intra- and interspecies-specific differences between wild and cultured fish for several trace elements. Several strong and moderate inter-elemental correlations in fish muscle were observed through correlation analysis. In our study, the mean levels of trace elements were still below the standard safety values for fish intended for human consumption. The same results were reached for all the parameters analyzed (international legal limits, estimated weekly intake, provisional tolerable weekly intake, target hazard quotient, target cancer risk), with trace element levels in fish below those that could pose a risk to human health. Consequently, these fish can be considered safe for human consumption. A better understanding of the levels of trace elements in fish would also better inform consumers about the potential risks of exposure to contaminants.

Depth-specific fluctuations of gene expression and protein abundance modulate the photophysiology in the seagrass Posidonia oceanica.

Here we present the results of a multiple organizational level analysis conceived to identify acclimative/adaptive strategies exhibited by the seagrass Posidonia oceanica to the daily fluctuations in the light environment, at contrasting depths. We assessed changes in photophysiological parameters, leaf respiration, pigments, and protein and mRNA expression levels. The results show that the diel oscillations of P. oceanica photophysiological and respiratory responses were related to transcripts and proteins expression of the genes involved in those processes and that there was a response asynchrony between shallow and deep plants probably caused by the strong differences in the light environment. The photochemical pathway of energy use was more effective in shallow plants due to higher light availability, but these plants needed more investment in photoprotection and photorepair, requiring higher translation and protein synthesis than deep plants. The genetic differentiation between deep and shallow stands suggests the existence of locally adapted genotypes to contrasting light environments. The depth-specific diel rhythms of photosynthetic and respiratory processes, from molecular to physiological levels, must be considered in the management and conservation of these key coastal ecosystems.

From mechanical to chemical impact of anchoring in seagrasses: The premises of anthropogenic patch generation in Posidonia oceanica meadows.

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 destruction. We chose to investigate the possible changes in the substrate chemistry given contrasted boat impacts. Our observations show that hydrogen sulfide concentrations remain high at 15 and 20m depth (42.6µM and 18.8µM) several months after the highest period of anchoring during the summer. Moreover, our multidisciplinary study reveals that anchoring impacts of large boats at 15 and 20m depth can potentially change the seascape structure. By taking into account both structural and chemical assessments, different managing strategies must be applied for coastal areas under anthropogenic pressures.

Towards a framework for assessment and management of cumulative human impacts on marine food webs.

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 used a case study of a Mediterranean seagrass (Posidonia oceanica) food web and expert knowledge elicitation in an application of the initial steps of a framework for assessment of cumulative human impacts on food webs. We produced a conceptual seagrass food web model, determined the main trophic relationships, identified the main threats to the food web components, and assessed the components' vulnerability to those threats. Some threats had high (e.g., coastal infrastructure) or low impacts (e.g., agricultural runoff) on all food web components, whereas others (e.g., introduced carnivores) had very different impacts on each component. Partitioning the ecosystem into its components enabled us to identify threats previously overlooked and to reevaluate the importance of threats commonly perceived as major. By incorporating this understanding of system vulnerability with data on changes in the state of each threat (e.g., decreasing domestic pollution and increasing fishing) into a food web model, managers may be better able to estimate and predict cumulative human impacts on ecosystems and to prioritize conservation actions.

Hacia un Marco de Trabajo para la Evaluación y el Manejo de los Impactos Humanos Acumulativos sobre las Redes Alimenticias Marinas Resumen El manejo efectivo con base en los ecosistemas requiere entender la respuesta de los ecosistemas a múltiples amenazas humanas en lugar de enfocarse en amenazas individuales. Para entender holísticamente la respuesta de los ecosistemas a las múltiples amenazas antropogénicas es necesario saber cómo estas amenazas afectan a los diferentes componentes dentro de los ecosistemas y cómo alteran finalmente el funcionamiento de los ecosistemas. Usamos el estudio de caso de la red alimenticia del pasto marino del Mediterráneo (Posidonia oceanica) y la obtención de conocimiento de expertos en una aplicación de los pasos iniciales de un método para la evaluación de los impactos humanos acumulativos sobre las redes alimenticias. Produjimos un modelo de red alimenticia de pastos marinos, determinamos las principales relaciones tróficas, identificamos a las principales amenazas para los componentes de la red y evaluamos la vulnerabilidad de los componentes a esas amenazas. Algunas amenazas tuvieron impactos altos (p. ej.: infraestructura costera) o bajos (p. ej.: escorrentía agrícola) sobre todos los componentes de la red, mientras que otros (p. ej.: carnívoros introducidos) tuvieron impactos muy diferentes sobre cada componente. Partir al ecosistema en sus componentes nos permitió identificar amenazas no vistas previamente y reevaluar la importancia de las amenazas percibidas comúnmente como mayores. Al incorporar este entendimiento de la vulnerabilidad del sistema con datos sobre los cambios en el estado de cada amenaza (p. ej.: disminución de la contaminación doméstica e incremento de la pesca) al modelo de red alimenticia, los manejadores pueden ser capaces de estimar y predecir de mejor manera los impactos humanos acumulativos sobre los ecosistemas y priorizar las acciones de conservación.

Differential cadmium and zinc distribution in relation to their physiological impact in the leaves of the accumulating Zygophyllum fabago L.

Cadmium and zinc share many similar physiochemical properties, but their compartmentation, complexation and impact on other mineral element distribution in plant tissues may drastically differ. In this study, we address the impact of 10 µm Cd or 50 µm Zn treatments on ion distribution in leaves of a metallicolous population of the non-hyperaccumulating species Zygophyllum fabago at tissue and cell level, and the consequences on the plant response through a combined physiological, proteomic and metabolite approach. Micro-proton-induced X-ray emission and laser ablation inductively coupled mass spectrometry analyses indicated hot spots of Cd concentrations in the vicinity of vascular bundles in response to Cd treatment, essentially bound to S-containing compounds as revealed by extended X-ray absorption fine structure and non-protein thiol compounds analyses. A preferential accumulation of Zn occurred in vascular bundle and spongy mesophyll in response to Zn treatment, and was mainly bound to O/N-ligands. Leaf proteomics and physiological status evidenced a protection of photosynthetically active tissues and the maintenance of cell turgor through specific distribution and complexation of toxic ions, reallocation of some essential elements, synthesis of proteins involved in photosynthetic apparatus or C-metabolism, and metabolite synthesis with some specificities regarding the considered heavy metal treatment.

Groundwater quality assessment of one former industrial site in Belgium using a TRIAD-like approach.

Contaminated industrial sites are important sources of pollution and may result in ecotoxicological effects on terrestrial, aquatic and groundwater ecosystems. An effect-based approach to evaluate and assess pollution-induced degradation due to contaminated groundwater was carried out in this study. The new concept, referred to as "Groundwater Quality TRIAD-like" (GwQT) approach, is adapted from classical TRIAD approaches. GwQT is based on measurements of chemical concentrations, laboratory toxicity tests and physico-chemical analyses. These components are combined in the GwQT using qualitative and quantitative (using zero to one subindices) integration approaches. The TRIAD approach is applied for the first time on groundwater from one former industrial site located in Belgium. This approach will allow the classification of sites into categories according to the degree of contaminant-induced degradation. This new concept is a starting point for groundwater characterization and is open for improvement and adjustment.