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Kunnskapsstøtte om miljøeffekter av kobber. Delrapport I
Get PDFVi har sammenstilt kunnskap om bruk av kobber som grohemmende middel på nøter i norsk oppdrettsnæring med hvor mye som kommer fra fôrspill og fekalier, med grenseverdier fra fôr, kystvann og sediment. Vi viser også kobbernivå målt i sediment fra overgangssonen og i fjernsonen og fra sedimentfeller etter periode med spyling. Økte nivå på grunn av utblødning fra nøter er modellert og mulige ekstrapulser på grunn spyling er målt og beskrevet.publishedVersio
Effekter av bunntråling - Sammenstilling av kunnskap om bunnpåvirkning fra trål og snurrevad relevant for norske farvann
Get PDFRapporten gir en sammenstilling av publisert kunnskap om hvordan bunnhabitater og bunndyr påvirkes (fysiske, kjemiske og biologiske effekter) av fiske med bunntrål og snurrevad. Det legges hovedvekt på påvirkninger fra fisketrål og reketrål som er relevant for norske forhold. Rapporten beskriver utbredelsen av sårbare habitater i norske havområder, og det presenteres kart som viser hvor det fiskes med fisketrål, reketrål og snurrevad. Bunntråling er den menneskelige aktiviteten som i geografisk utstrekning har størst påvirkning på havbunnen.publishedVersio
Quick and efficient microplastic isolation from fatty fish tissues by surfactant-enhanced alkaline digestion
Get PDFFor monitoring microplastic contamination in fish tissues, tissue digestion into filterable components prior to microplastic identification and quantification should be quick and efficient, providing satisfying microplastic recoveries of relevant particle sizes. Filtration with a small pore size, necessary to target small particles, is a challenge. Some proposed protocols take several days. To improve this, a combination of surfactants (Tween®-20 and Triton™ X-100) with potassium hydroxide (KOH) and pH neutralization was used. Fish bones were removed in tissue preparation prior to digestion. Recovery down to ca. 60–80 μm worked well for PA-66, PE, PET, PP, PS and PVC. In conclusion, we developed a comparatively swift digestion protocol, enabling filtration of 100 g samples with a pore size of 10 μm, for fish fillets with high (mackerel), intermediate (salmon, plaice) and low (cod) fat contents, fish liver, head kidney and oil samples, within 16–24 h.publishedVersio
Transforming sustainable aquaculture by applying circularity principles
Get PDFA circular economy is considered one way to reduce environmental impacts of human activities, by more efficient use of resources and recovery, resulting in less waste and emissions compared to linear take-make-dispose systems. Muscat et al. developed five ecological principles to guide biomass use towards a circular economy. A few studies have demonstrated environmental benefits of applying these principles to land-based food systems, but to date, these principles have not been explored in aquaculture. The current study expands on these principles and provides a narrative review to (i) translate them to aquaculture, while identifying implications for the main species and production systems, and (ii) identify the main pathways to make aquaculture more circular. We show that the underlying concepts of the ‘safeguard’, ‘entropy’, and ‘recycle’ principles have been well researched and sometimes well implemented. In contrast, the ‘avoid’ and ‘prioritise’ principles have been explored much less; doing so would provide an opportunity to decrease environmental impacts of aquaculture at the food-system level. One example is prioritising the production of species that contribute to food and nutrition security, have low environmental impacts and thinking at wider food system scale to avoid feed-food competition in aquaculture. We identified six priorities that could make aquaculture more circular: (i) increase production and demand for the most essential species, (ii) decrease food loss and waste at farm and post-harvest stages, (iii) support nutrient recycling practices at multiple scales, (iv) adapt aquafeed formulations, (v) inform consumers about benefits of species of low trophic levels and other environmentally friendly aquatic foods, and (vi) address urgent research gaps.publishedVersio
Genomic insights into Enterococcus faecium isolates from marine bivalves highlight One Health concerns and healthcare linkages
Get PDFEnterococci, especially Enterococcus faecium, are one of today’s leading causes of multidrug-resistant infections in hospital settings. The marine environment may harbour enterococci, but its role as an evolutionary niche and as a vector for the spread of enterococci is sparsely investigated. Hence, by applying enterococci in bivalves as a sentinel tool, this study aimed to describe the prevalence of enterocooci along the Norwegian coast and in addition the phylogeny of E. faecium in particular. Enterococci in batch samples of marine bivalves, harvested from 86 different locations, were quantitatively examined by a culture-dependent most probable number (MPN) method. Isolates were identified by MALDI-TOF-MS prior to antimicrobial susceptibility testing by broth microdilution. In-detail analyses of a representative selection of E. faecium isolates (n=148) were done by Illumina whole-genome sequencing, and assembled genomes were compared to closed E. faecium genomes in the public databases and to genomes from commensal and clinical isolates from Norway. Diversity among E. faecium within the same batch sample of bivalves was also explored. Enterococci were detected in 287 of the 471 examined bivalve samples, but in low concentrations with a median value of <18 MPN /100 g. From positive samples, 479 isolates of enterococci were identified belonging to ten different species, where E. faecium (n=247), Enterococcus hirae (n=114) and Enterococcus faecalis (n=66) were most frequently found. Resistance towards one or more antimicrobial agents was observed in 197 isolates (41 %), none of the isolates showed acquired resistance to vancomycin or linezolid. Phylogenetic analyses revealed high diversity among the E. faecium isolates and showed that the marine niche is dominated by strains from the non-clinical setting belonging to clade A2 (n=85) and B (E. lactis) (n=60). Only three isolates belonged to the hospital-associated clade A1 (ST80 and ST117). Two of these clustered with one isolate from a hospitalized patient and one from a non-hospitalized person. This study demonstrated a high prevalence, but low concentrations of enterococci in bivalves, and low levels of antimicrobial resistance. E. faecium genomes showed high population diversity and that very few E. faecium isolates in bivalves may have arisen from the human healthcare system. A systematic surveillance of target micro-organisms applying methods examining multiple isolates from the same bivalve sample provides important data to assess the enterococcal phylogeny, antimicrobial resistance and the level of faecal pollution in the marine environment.publishedVersio
Assessment of genetically modified maize MON 87419 for food and feed uses, import and processing under Regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2017-140)
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Inorganic carbon and nutrient dynamics in the marginal ice zone of the Barents Sea: Seasonality and implications for ocean acidification
Get PDFThe Barents Sea is a productive Arctic shelf sea experiencing Atlantification with ocean warming, sea ice loss and increased influence of Atlantic Water. The impact of these changes on inorganic carbon and nutrient dynamics and ocean acidification are yet to be fully understood. Seasonal variability and drivers of inorganic carbon and nutrients were determined from south of the Polar Front at 76 °N in the Barents Sea to 82 °N in the Nansen Basin, Arctic Ocean, encompassing Atlantic and Arctic regimes in summer (August 2019), winter (December 2019), winter/spring (March 2021) and spring (May 2021). Summer sea-ice meltwater was the main driver reducing total alkalinity (AT) and dissolved inorganic carbon (CT), corresponding to 55 % and 81 % of the total changes ΔCT and ΔAT, respectively, in the surface layer. Primary production reduced CT (37 % of ΔCT) and nutrients, particularly in ice-free waters, increasing calcium carbonate (CaCO3) saturation for aragonite (Ωaragonite) from 1.3 in spring to 2.3 in summer. Net community production (NCP) in the upper 50 m was highest (1.3 mol C m−2) in the Atlantic Water regimes and lowest (0.4 mol C m−2) in the ice-covered Nansen Basin in summer. Mixing, organic matter remineralisation and CO2 uptake enriched AT, CT and nutrients to pre-condition the water column from winter to early spring. Formation and dissolution of CaCO3 from shells and ikaite in sea ice (5–13 % of ΔAT) represented a minor AT source from winter to spring. Highest NCP by spring (0.3 mol C m−2) occurred in a transient Atlantic-like regime over the shelf slope. Atmospheric CO2 uptake contributed up to 37 % of ΔCT and the region was an annual CO2 sink. Sea-ice processes and deep winter convection lowered AT and Ωaragonite (1.12–1.14) to enhance the risk of acidification over the shelf. Future Atlantification may increase biological production, reduce meltwater dilution effects and counteract acidification in the Barents Sea. The observations reveal the importance of seasonal and spatial studies to capture variability in inorganic carbon and nutrient cycling, driven by numerous processes coupled to the ice-ocean system that may exacerbate or alleviate ocean acidification in Arctic shelf seas.publishedVersio
The evolving story of catadromy in the European eel (Anguilla anguilla)
Get PDFAnguillid eels were once considered to be the classic example of catadromy. However, alternative life cycles have been reported, including skipping the freshwater phase and habitat shifting between fresh, brackish, and saltwater throughout the growth phase. There is a lack of knowledge regarding these alternate life strategies, for example, the proportion of individuals in the population that adopt them compared to classic catadromy. We provide a description of these alternate life cycle strategies in temperate anguillids, their possible drivers, and the methods available to investigate them. These methods (lethal and non-lethal), include otolith microchemistry, fatty acid and stable isotope analyses, parasite identification, blood transcriptomics, and electronic tags. We argue that since the current management framework for the European eel and other temperate eels is based mainly on the freshwater component of the population, it ignores eels growing in saline waters. Many of the factors that are thought to be responsible for the precipitous decline of the eel population are more prevalent in freshwater systems. Therefore, the contribution of saline eels may be more important than currently estimated. The habitat-shifting ability of eels may be all the more crucial for the persistence and recovery of those species that are endangered.publishedVersionpublishedVersio
Impacts of glacial and sea-ice meltwater, primary production and ocean CO2 uptake on ocean acidification state of waters by the 79 North Glacier and northeast Greenland shelf
Get PDFThe waters adjacent to the Nioghalvfjerdsbræ (79 North Glacier, 79NG) are influenced by Greenland Ice Sheet (GrIS) melt, sea-ice meltwater, and waters on the adjacent northeast Greenland shelf (NEGS). We investigated ocean acidification (OA) variables and the role of freshening, primary production, and air-sea CO2 exchange in Dijmphna Sound (DS) and on the NEGS in the summers of 2012 and 2016. The upper 150 m consisted of Polar Water with Arctic origin that was divided into a fresh surface layer (SL<50 m) and a cold halocline layer (CHL, 50 to 150 m). The layer below 150 m was of Atlantic origin. The SL freshwater was larger in 2012 than in 2016, mainly originated from local 79NG (and GrIS) runoff in DS, whereas on the NEGS in both years, it was mainly from sea-ice melt. The lowest aragonite saturation state (ΩAr) of 1.13 was found in the SL in 2012. Biological CO2 drawdown at primary production caused increased ΩAr in SL, which compensated for most of the ΩAr decrease due to the freshwater dilution of carbonate ions reducing total alkalinity, hence preventing corrosive conditions. This was most pronounced near the 79NG front in 2012, where surface stratification was most pronounced coinciding with large glacial meltwater fractions. Freshening decreased ΩAr by 0.4 at the 79NG front was compensated by biological CO2 drawdown by ~0.5. In 2016, a well-mixed water column in DS and NEGS, with dilution by sea-ice meltwater, caused less compensation on ΩAr by biological CO2 drawdown than in 2012. In future with changing climate and changing ocean chemistry, the increased meltwater effects may overcome the alleviating effects of biological CO2 drawdown on OA with unfavorable conditions for calcifying organisms. However, our study also suggests that primary production may be stimulated by stratification from surface meltwater. In addition, Atlantification and subglacial discharge may result in upwelling of inorganic nutrients that could promote primary production.publishedVersio