The University of Tromsø – The Arctic University of Norway (Norwegian: Universitetet i Tromsø – Norges arktiske universitet; Northern Sami: Romssa universitehta – Norgga árktalaš universitehta) is the world's northernmost university. Located in the city of Tromsø, Norway, it was established in 1968, and opened in 1972. It is one of ten universities in Norway. The University of Tromsø is the largest research and educational institution in Northern Norway and the sixth-largest university in Norway. The University's location makes it a natural venue for the development of studies of the region's natural environment, culture, and society. The main focus of the University's activities is on auroral light research, space science, fishery science, biotechnology, linguistics, multicultural societies, Saami culture, telemedicine, epidemiology and a wide spectrum of Arctic research projects. The close vicinity of the Norwegian Polar Institute, the Norwegian Institute of Marine Research and the Polar Environmental Centre gives Tromsø added weight and importance as an international centre for Arctic research. Research activities, however, are not limited to Arctic studies. The University researchers work within a broad range of subjects and are recognised both nationally and internationally. On 1 January 2009, the University of Tromsø merged with Tromsø University College. On 1 August 2013, the university merged with Finnmark University College to form Universitetet i Tromsø – Norges arktiske universitet (The University of Tromsø – The Arctic University of Norway), thereby adding campuses in Alta, Hammerfest and Kirkenes. On 1 January 2016, Narvik University College and Harstad University College merged with UiT - The Arctic University of Norway. As of January 2016 the university now has six campus locations in northern Norway, the main campus being Tromsø.
Gas hydrates are widespread under the seafloor along continental margins, where high-pressure and low-temperature conditions ensure their stability. They represent a significant potential energy resource; however, their exploitation poses serious environmental and climatic risks, including submarine slope failures, tsunamis, climate warming, ocean acidification and oxygen depletion. Many hyperthermal events and associated biotic crises have been linked to large-scale destabilisation of gas hydrates. These assumptions are based primarily on circumstantial evidences, as distinctive hydrate-related rocks have not been documented in sedimentary successions coeval to these events. Despite this, gas hydrates must have existed since at least the Neoproterozoic, suggesting that their geological record is underrepresented, and their role in Earth history remains elusive. Recognising vestiges of past gas hydrates is, therefore, essential for the understanding of their impact on ancient geosystems and their potential contribution to near-future climate change. This review aims to enhance the identification of past gas hydrate occurrences in marine settings by: (1) outlining their distribution, occurrence, dynamics and associated geohazards in modern environments; (2) summarising current perspectives on their role in Earth history; (3) reviewing their sedimentological and geochemical vestiges in the sedimentary record. Particular emphasis is posed on the most reliable archive of past gas hydrates: hydrate-derived authigenic carbonates; (4) clarifying existing confusion in terminology and proposing a comprehensive classification of gas hydrate-associated rocks; and (5) identifying the most promising research directions and methods in this field.
Multimodal imaging integrates complementary contrasts to improve the understanding of physiological processes and disease progression. In this review, we aim to summarize and critically assess the integration of optoacoustic microscopy (OAM) with established ultrasound-based and optical microscopy-based modalities, addressing how these hybrid systems enhance structural, functional, and molecular imaging across biomedical applications. A comprehensive literature review was conducted focusing on OAM-based multimodal microscopy platforms integrated with ultrasound microscopy and optical techniques, including optical coherence tomography, fluorescence microscopy, multiphoton microscopy, light-sheet microscopy, and Raman spectroscopy. Emerging strategies such as integration with quantitative phase imaging and advanced signal processing approaches, including the multiple signal classification algorithm, were also examined. Studies were analysed with respect to system design, image co-registration and fusion strategies, and application domains including oncology, dermatology, ophthalmology, and neuroscience. Multimodal OAM platforms demonstrated enhanced imaging performance by combining high optical contrast with improved penetration depth and functional sensitivity. These systems enabled detailed visualization of oxygenation, tumor angiogenesis, skin microarchitecture, retinal structures, and neuronal activity. Comparative analysis revealed trade-offs and synergies among modalities in terms of spatial resolution, penetration depth, frame rate, and field-of-view, highlighting the advantages of hybrid configurations over single-modality approaches. Hybrid OAM-based multimodal microscopy provides a powerful framework for comprehensive biomedical imaging. By leveraging complementary contrasts and advanced image fusion strategies, these platforms hold strong potential to advance both fundamental research and translational clinical applications.
Marine nematodes dominate the meiofauna of benthic sediments, but few have investigated their trophic roles. We studied the eukaryote diet composition of nematodes from sediments on the Arctic Barents Sea shelf, shelf break and adjacent Nansen Basin, during four seasons, using prey metabarcoding of the 18S ribosomal RNA gene. Monhysterida (n = 35 individuals), Chromadorida (34), Araeolaimida (27) and Enoplida (22) nematodes were most frequently observed across the study area, and diets were composed of diverse metazoan, fungal, and protist prey. In contrast to ambient sediment communities, prey followed a strong seasonal pattern, and ordination indicated two distinct seasonal prey clusters. In March and May prey were characterized by high relative abundances of fungi (42
Abstract Background Plant-plant positive interactions are among the main drivers of plant community structure, especially in stressful environments. While the ecological dynamics of such facilitation are increasingly understood, studies evaluating the importance of nurse plants in preserving phylogenetic diversity and protecting species of medicinal value and conservation concern are still limited. Here, we investigated the nurse effects of a Himalayan endemic shrub, Berberis angulosa, in promoting taxonomic richness, composition and phylogenetic diversity of overall and highly valued species in the high-elevation mountain landscape of Langtang National Park, Nepal. Using pair-wise sampling design, we recorded plant communities within the patches of Berberis shrubs and in open gaps at three altitudinal belts. Results Compared to adjacent open areas, Berberis patches were found to harbor compositionally distinct and evolutionarily diverse lineage plant communities with significantly higher average overall and human-valued species richness. Relative interaction indices showed clear patterns along an elevation gradient with the strongest facilitation observed at highest elevations. Comparisons of phylogenetic diversity across elevations showed inconsistent patterns, whereas overall metrics indicated higher phylogenetic diversity in shrub habitats for human-valued species. Facilitation by Berberis enhanced community-level richness by 40% (39 species; total = 97), including 19 human-valued species (~ 36%; total = 53) that occurred exclusively within shrub canopies. Many medicinal, endemic and conservation priority species were either shrub specialists or had significant association with Berberis patches, illustrating the protective role of the nurse shrub. Conclusions Our results demonstrate that the facilitative effect of Berberis is not only crucial in maintaining plant communities with diverse evolutionary histories but also equally contributing to local beta and landscape-scale gamma biodiversity, sustaining valuable ecosystem services and benefits to human communities in the Himalayas. These findings suggest that appropriate management of such nurse plants may constitute a nature-based approach to biodiversity conservation, that should be considered in policies for sustainability, resilience, and ecosystem functioning in this high-elevation alpine system.
Non-native pink salmon (Oncorhynchus gorbuscha) have increased rapidly in Norwegian rivers since 2017, yet their marine ecology remains poorly understood. To assess variation in marine growth, we analysed scales from 476 individuals returning to northern (Barents Sea region) and central (Atlantic region) Norway in 2019 and 2021. Clear differences in growth and body size emerged between regions and years, with fish returning in 2019 experiencing the poorest growth and reaching the smallest adult size. Differences in growth histories indicate that pink salmon captured in the two regions may have experienced distinct marine feeding resource conditions, possibly because they followed different migratory pathways, beginning in the first weeks at sea. Approximately one-third of individuals experienced distinct periods of depressed growth during their first spring and summer at sea, and these events were more common among fish returning to central Norway. Mid- to late-season growth during the first year at sea strongly influenced adult size, highlighting the importance of favourable conditions during this period. At the same time, it was shown that growth after the winter could more than compensate for poor growth up until then. The pronounced variability in growth performance suggests that environmental conditions during the marine phase strongly shape adult size and may influence the future invasion potential of pink salmon in the North Atlantic. As this invasive species continues to expand, continued monitoring of growth and improved understanding of their marine ecology and environmental drivers of growth will be essential for anticipating invasion dynamics and impacts on native ecosystems.
