An accurate representation of the particle organic matter (POM) footprint is necessary in order to effectively predict impacts upon benthic communities and the risk of excessive organic enrichment beneath aquaculture sea-cages. Consequently, bottom-related processes such as particle resuspension must be adequately parametrized and evaluated in the available numerical models. We implemented two approaches to model POM resuspension in a Lagrangian particle tracking model and compared their influence on footprint extension and gradients of depositional flux against a no-resuspension scenario. We performed simulations in both exposed and protected aquaculture locations, and at different stages of the Atlantic Salmon (Salmo salar) production cycle in Norway. Our results indicate that the use of sediment-dependent thresholds for resuspension has the potential to regulate the high levels of erosion produced when selecting a low critical value in constant-threshold approaches, particularly in dynamic environments with mixed sediment types. | publishedVersion

peer reviewed | 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.

Diarrhetic shellfish poisoning (DSP) toxins and pectenotoxins (PTX) produced by endemic species of the genus Dinophysis, mainly D. acuta and D. acuminata, pose a big threat to public health, artisanal fisheries and the aquaculture industry in Southern Chile. This work reports the first detection of lipophilic toxins, including pectenotoxin-2 (PTX-2) and gymnodimine-A (GYM-A), in hard razor clam (Tagelus dombeii) associated with an unprecedented spring bloom −38.4 × 103 cells L−1 in integrated hose sampler (0–10 m) – of Dinophysis acuminata in coastal waters of central Chile. The socio-economic challenges to small-scale fisheries are discussed. The study points to the pressing need for sound policies to face unexpected HAB event, probably due to biogeographical expansions, with a focus on fisheries management, participation of stakeholders, and development of adaptive capacities.

Impulsive sounds generated during seismic surveys have elicited behavioral responses in marine mammals and could cause hearing impairment or injury. Mitigating exposure to seismic sound often relies on real-time marine mammal detection. Detection performance is influenced by detection method, environmental conditions, and observer experience. We conducted a field comparison of real-time detections made by marine mammal observers (MMOs), a rotating infrared (IR) camera, and via passive acoustic monitoring (PAM). Data were collected from a 38 m research vessel offshore Atlantic Canada. Our results indicate that overall detection rates increase when complementary methods are used. MMOs and PAM are likely the most effective combination during high seas and precipitation. PAM and IR can be used in darkness. In good visibility, MMOs with IR or PAM should increase detections. Our results illustrate the importance of addressing false positive IR detections, matching system capabilities to sea conditions/species of interest, and employing experienced observers.

Author's accepted version (postprint). | This is an Accepted Manuscript of an article published by Springer in Water, Air and Soil Pollution on 27/10/2018. | Available online: https://link.springer.com/article/10.1007/s11270-018-4013-9 | acceptedVersion

An in situ particle imaging system for measurement of high concentrations of suspended particles ranging from 30 μm to several mm in diameter, is presented. The system obtains quasi-silhouettes of particles suspended within an open-path sample volume of up to 5 cm in length. Benchmarking against spherical standards and the LISST-100 show good agreement, providing confidence in measurements from the system when extending beyond the size, concentration and particle classification capabilities of the LISST-100. Particle-specific transmittance is used to classify particle type, independent of size and shape. This is applied to mixtures of oil droplets, gas bubbles and oil-coated gas bubbles, to provide independent measures of oil and gas size distributions, concentrations, and oil-gas ratios during simulated subsea releases. The system is also applied to in situ measurements of high concentrations of large mineral flocs surrounding a submarine mine tailings placement within a Norwegian Fjord. | publishedVersion

Los ecosistemas de la cuenca mediterránea, su biodiversidad única y los servicios clave que brindan están actualmente en riesgo debido a la contaminación del aire y el cambio climático; sin embargo, solo un número limitado de estudios aislados y geográficamente restringidos han abordado este tema, a menudo con resultados contrastantes. Las particularidades de la contaminación del aire en esta región incluyen altos niveles de O3 debido a las altas temperaturas del aire y la radiación solar, la estabilidad de las masas de aire y el predominio de la deposición seca de nitrógeno sobre la húmeda. Además, los factores abióticos y bióticos únicos (por ejemplo, el clima, el tipo de vegetación, la relevancia de los aportes de polvo del Sahara) que modulan la respuesta de los ecosistemas mediterráneos en diversas escalas espaciotemporales hacen que sea difícil comprender y, por tanto, predecir, las consecuencias de las actividades humanas que causan la contaminación del aire. Contaminación en la Cuenca Mediterránea. Por lo tanto, existe una necesidad urgente de implementar plataformas experimentales y de investigación coordinadas junto con redes más amplias de monitoreo ambiental en la región. En particular, es crucial contar con una red sólida de monitoreo de deposiciones junto con estimaciones de modelos, que posiblemente incluyan un conjunto de biomonitores comunes (idealmente criptógamas, un componente importante de la vegetación mediterránea), para ayudar a perfeccionar los mapas de deposición de contaminantes. Además, se debe prestar mayor atención a las medidas de diversidad funcional en futuros estudios sobre la contaminación del aire y el cambio climático para establecer el vínculo necesario entre la biodiversidad y la provisión de servicios ecosistémicos en los ecosistemas mediterráneos. A través de un esfuerzo coordinado, la comunidad científica mediterránea puede llenar los vacíos mencionados anteriormente y alcanzar una mayor comprensión de los mecanismos subyacentes a los efectos combinados de la contaminación del aire y el cambio climático en la cuenca mediterránea.

This study documents the occurrence of microplastic (< 5 mm), mesoplastics (5–20 mm) and macroplastic (> 20 mm) in Atlantic cod (Gadus morhua), a common and economically important species of marine fish in Norway. Fish stomachs (n = 302) were examined from six different locations along the coast of Norway. Three percent of the individual stomachs contained items identified by Fourier transform infrared spectroscopy (FTIR) as synthetic polymers. Bergen City Harbour was a hotspot with 27% of the cod examined found to contain plastic. Polyester was the most frequently detected polymer. All bar one of the stomachs that contained plastic were full of organic stomach content, suggesting a plastic gut clearance rate similar to the ingested food. It is proposed that stomach fullness is an important metric in order to avoid underestimations when assessing the levels of microplastic ingested by fish. | acceptedVersion

peer reviewed | Polycyclic aromatic hydrocarbons (PAHs) are pollutants that occur in mangrove sediments. Their removal by bacteria often depends on specific characteristics as the number of benzene rings they possess and their solubility. Their removal also depends on environmental factors, such as pH, temperature, oxygen, and the ability of the endogenous or exogenous microflora to metabolize hydrocarbons.With the aim of treating mangrove sediments polluted by hydrocarbons in a biological way, a biodegradation experiment was conducted using mangrove sediments artificially contaminated with a mixture of four PAHs. The study used Rhodococcus erythropolis as an exogenous bacterial strain in order to assess the biodegradation of the PAH mixture by natural attenuation, biostimulation, bioaugmentation, and a combination of biostimulation and bioaugmentation. The results showed that the last three treatments were more efficient than natural attenuation. The biostimulation/bioaugmentation combination proved to be the most effective PAH degradation treatment.