Armoracia rusticana (AR) was tested for antimicrobial and antioxidants power. The compound demonstrated to inhibit fish pathogens such as Vibrio anguillarum, V. harvey, V. alginolyticus, Aeromonas hydrophila, A. salmonicida, Photobacterium damselae subspecie piscicida, Tenacibaculum marinum and Pseudomonas anguilliseptica,. The total phenolic content and the reducing power resulted higher in the water extract of AR, respect to the hydroalcoolic. In vitro test demonstrated that AR significantly protect cells against death, induced by oxidative stress.

We assessed fungal diversity in water and sediment samples obtained from five Arctic lakes in Ny-Ålesund (Svalbard Islands, High Arctic) and five Antarctic lakes on Livingston and Deception Islands (South Shetland Islands), using DNA metabarcoding. A total of 1,639,074 fungal DNA reads were detected and assigned to 5980 ASVs amplicon sequence variants (ASVs), with only 102 (1.7%) that were shared between the two Polar regions. For Arctic lakes, unknown fungal taxa dominated the sequence assemblages, suggesting the dominance of possibly undescribed fungi. The phylum Chytridiomycota was the most represented in the majority of Arctic and Antarctic samples, followed by Rozellomycota, Ascomycota, Basidiomycota, and the less frequent Monoblepharomycota, Aphelidiomycota, Mortierellomycota, Mucoromycota, and Neocallimastigomycota. At the genus level, the most abundant genera included psychrotolerant and cosmopolitan cold-adapted fungi including Alternaria, Cladosporium, Cadophora, Ulvella (Ascomycota), Leucosporidium, Vishniacozyma (Basidiomycota), and Betamyces (Chytridiomycota). The assemblages displayed high diversity and richness. The assigned diversity was composed mainly of taxa recognized as saprophytic fungi, followed by pathogenic and symbiotic fungi.

Plastic pollution is a global emerging concern, but in the Arctic Ocean, the role of the plastisphere as a potential carrier of pathogens and antibiotic-resistant bacteria is unknown yet. An initial assessment of the spread of these target bacteria through their colonization of plastic particles, attributed to the micro-sized fraction (less than 5 mm, named microplastics, MPs), was carried out across the 75° N transect (Greenland Sea). To fill the knowledge gaps regarding the bacterial community associated withmicroplastics (MPs)—belonging to the so-called “plastisphere”—and the potential risks related to their spread, our study focused on the abundance and taxonomic composition of the plastisphere, including potential pathogenic and antibiotic-resistant bacteria, using a culture-dependent approach. MPs particles were collected through a Manta net, and decimal dilutions were cultured on Marine agar plates to estimate the abundance of culturable heterotrophic bacteria. For the search of target pathogenic bacterial species (Escherichia coli, Enterococcus spp., Salmonella spp., potentially pathogenic Vibrio spp., and Staphylococcus aureus), small volumes were inoculated into selective culture media using aspread plate directly or after enrichment. Screening of the antibiotic susceptibility profiles of the bacterial isolates was performed to assess the presence of antibiotic-resistant bacteria. The culturable heterotrophic bacterial community was dominated by members of the phyla Gammaproteobacteria and Actinobacteria, with bacterial isolates assigned to the genera Psychrobacter, Pseudoalteromonas, Shewanella, and Arthrobacter. Selective enrichments resulted in the detection of target bacterial pathogens, mostly identified as potentially pathogenic Vibrios spp., in the examined samples. The antibiotic susceptibility profiles pointed out that multiple antibiotic-resistant bacteria were also isolated, suggesting the need to shed light on the potential risks to human and animal health deriving from the plastisphere in remote cold regions as well.

The sea bottom acts as a key natural archive where the memory of long-term timescale environmental changes is recorded. This study discusses some ecological and chemical features of fjord sediments that were explored during the AREX cruise carried out in the Svalbard archipelago in the summer of 2021. The activity rates of the enzymes leucine aminopeptidase (LAP), beta-glucosidase (GLU), and alkaline phosphatase (AP) and community-level physiological profiles (CLPPs) were studied with the aim of determining the functional diversity of the benthic microbial community, while bacterial isolates were screened for their susceptibility to antibiotics in order to explore the role of these extreme environments as potential reservoirs of antibiotic resistance. Enzyme activity rates were obtained using fluorogenic substrates, and CLPPs were obtained using Biolog Ecoplates; antibiotic susceptibility assays were performed through the standard disk diffusion method. Spatial trends observed in the functional profiles of the microbial community suggested variability in the microbial community’s composition, presumably related to the patchy distribution of organic substrates. Complex carbon sources, carbohydrates, and amino acids were the organic polymers preferentially metabolized by the microbial community. Multi-resistance to enrofloxacin and tetracycline was detected in all of the examined samples, stressing the role of sediments as a potential reservoir of chemical wastes ascribable to antibiotic residuals. This study provides new insights on the health status of fjord sediments of West Spitsbergen, applying a dual ecological and biochemical approach. Microbial communities in the fjord sediments showed globally a good functional diversity, suggesting their versatility to rapidly react to changing conditions. The lack of significant diversification among the three studied areas suggests that microbial variables alone cannot be suitable descriptors of sediment health, and that additional measures (i.e., physical–chemical characteristics) should be taken to better define environmental status.

Microorganisms play a key role in ecosystem functions and maintaining ecological balance, but their communities are sensitive to environmental stressors like climate change, eutrophication, and chemical pollution. This study investigated water samples from Arctic and Antarctic lakes to measure concentrations of persistent organic pollutants (POPs)-including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated naphthalenes (PCNs), chlorobenzenes (CBs)-and trace metals. Simultaneously, bacterial community composition was analyzed using 16S rRNA gene sequencing to explore correlations between contamination and microbial diversity. A comparative approach evaluated different environmental filtering in contaminant profiles and bacterial assemblages between the two poles, representing one of the first studies to combine chemical and microbial data in polar lacustrine ecosystems. Results showed notable differences in taxonomic richness and community composition, with both regions dominated by Proteobacteria and Bacteroidota, though most variation occurred at finer taxonomic levels. Contaminant profiles differed geographically: Antarctic lakes, especially near local human activities, had higher PCBs and PCNs, while Arctic lakes showed more PAHs and CBs, suggesting different contaminant sources or transport pathways. Trace metal distribution in Antarctic lakes varied spatially, influenced by local geology and potentially by biogeochemical effects of penguin populations. Preliminary observations reveal consistent and region-specific correlations between contaminant distribution patterns and bacterial community composition, pointing to potentially significant ecological linkages that merit deeper and systematic investigation. Understanding contaminant-microbe interactions is crucial for assessing ecosystem responses in these vulnerable polar environments.