NORCE Research Archive
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Dalselva – Fiskebiologiske undersøkelser i perioden 2020–2022
Get PDFDalselva ligger i Framfjord i Vik kommune, og rundt 75 % av nedbørfeltet er overført til en kraftstasjon i Vik, noe som kan føre til svært lav vannføring i elva. NORCE LFI har gjennomført fiskebiologiske undersøkelser i Dalselva fra 2020 til 2022 for å overvåke fiskebestandene og vurdere fysiske tiltak. Tettheten av ensomrig aure (0+) varierer mellom 2,7 og 163 pr. 100 m2 i den anadrome strekningen, med et gjennomsnitt på 36, mens tettheten oppstrøms vandringshinderet er 8 pr. 100 m2. Tettheten av eldre aure (>0+) i den anadrome strekningen er i snitt 29 pr. 100 m2, mot 14 pr. 100 m2 oppstrøms. Det har vært en negativ utvikling i auretettheten i den anadrome strekningen siden 2002, mens dette ikke er like tydelig oppstrøms. Kunnskapen om laks og sjøaure i Dalselva er begrenset, men Vitenskapelig råd for lakseforvaltning klassifiserer sjøaurebestanden som moderat og peker på vannkraftreguleringen som en betydelig påvirkningsfaktor. Lakselus har en moderat effekt. Laksebestanden er lav og ustabil, med varierende gytebestander av sjøaure. Predasjon fra oter kan også påvirke bestandene betydelig. Tidligere undersøkelser har foreslått habitattiltak som å legge ut stein og trær for å skape skjul for ungfisk og å bygge fiskepassasje opp juvet for å forlenge den anadrome strekningen. Det er også anbefalt å etablere en stasjon for å måle vannføringen i elva og fortsette med årlige undersøkelser av gytebestand og ungfisk.publishedVersio
Techno-Economic Evaluation of Carbon Capture, Utilisation and Storage; Case Study of Scenarios in Western Macedonia, Greece
Get PDFOver the previous decades, the region of Western Macedonia in Greece has become home to heavy industrial clusters. Carbon capture, utilisation, and storage (CCUS) is an essential technology for climate change mitigation that could deliver significant economic growth. As part of the EU-funded STRATEGY CCUS project (2019-2022), two scenarios were developed and economically evaluated for the deployment of CCUS technologies in Western Macedonia. These scenarios were created using a novel software tool to analyse the CCUS business model in the Greek region. For this, two suitable local onshore geological sites were utilised for storing captured CO2. Five industries from different industrial sectors have been chosen for CO2 utilisation. Key Performance Indicators (KPIs) were calculated to measure this project’s long-term value and return on investment (ROI) while also measuring its short-term efficiency and profitability over the deployment process lifetime.publishedVersio
Dynamic Response to Ice Shelf Basal Meltwater Relevant to Explain Observed Sea Ice Trends Near the Antarctic Continental Shelf
Get PDFObserved Antarctic sea ice trends up to 2015 have a distinct regional and seasonal pattern, with a loss during austral summer and autumn in the Bellingshausen and Amundsen Seas, and a year-round increase in the Ross Sea. Global climate models generally failed to reproduce the magnitude of sea ice trends implying that the models miss relevant mechanisms. One possible mechanism is basal meltwater, which is generally not included in the current generation of climate models. Previous work on the effects of meltwater on sea ice has focused on thermodynamic processes. However, local freshening also leads to dynamic changes, affecting ocean currents through geostrophic balance. Using a coupled ocean/sea-ice/ice-shelf model, we demonstrate that basal melting can intensify coastal currents in West Antarctica and the westward transport of sea ice. This change in transport results in sea ice anomalies consistent with observations, and may explain the disparity between climate models and observations.publishedVersio
Characterizing Reef Net Metabolism Via the Diel Co-Variation of pH and Dissolved Oxygen From High Resolution in Situ Sensors
Get PDFCoral reefs are subject to degradation by multiple environmental stressors which are predicted to intensify. Stress can alter ecosystem composition, with shifts from hard coral to macroalgae dominated reefs often accompanied by an increase in soft corals and sponges. Such changes may alter net ecosystem metabolism and biogeochemistry by shifting the balance between photosynthesis, respiration, calcification and dissolution. We deployed high temporal resolution pH and dissolved oxygen (DO) sensors at four Caribbean reef sites with varying covers of hard and soft corals, sponges and macroalgae. The resultant data indicated that the strength of the “metabolic pulse”, specifically the co-variation in daily pH and DO oscillations, was driven by the net balance of light -dependent and -independent metabolism. pH and DO were positively correlated over the diel cycle at coral dominated sites, suggesting that photosynthesis and respiration were the major controlling processes, and further indicated by agreement with a simple production:respiration model. Whereas, at a site with high macroalgal cover, pH and DO decoupling was observed during daylight hours. This indicates that an unidentified light-driven process altered the expected pH:DO relationship. We hypothesize that this could be mediated by the higher levels of macroalgae, which either stimulated bacterial-mediated carbonate dissolution via the production and release of allelopathic compounds or retained oxygen, evolved during photosynthesis, in the gaseous form in seawater (ebullition). Our work demonstrates that high resolution monitoring of pH and DO provides insight into coral reef biogeochemical functioning and can be key for understanding long-term changes in coral reef metabolism.publishedVersio
Utredning av sirkulærøkonomien i sjømatnæringen
Get PDFUtredningen har fremskaffet et bredt kunnskapsgrunnlag for videre arbeid innen sirkulær økonomi i sjømatnæringen. Arbeidet har identifisert status, kunnskapsbehov, muligheter og utfordringer for at næringen skal nå forventningene om sirkulærøkonomi. Det er store muligheter for økt sirkularitet i norsk sjømatproduksjon, men det er også barrierer/hindringer i sjømatnæringen. En bedre utnyttelse av ressurser innen sjømatnæringen, inkludert redusert tap av sjømat og restråstoffer og økt resirkulering av plast og andre materialer, kan føre til flere arbeidsplasser innen næringen selv og tilhørende næringer som landbruk (industriell symbiose) samt nye verdikjeder. Arbeidet viser til at sirkulærøkonomi er mer enn resirkulering. Nøkkelen ligger i å gjenoppbygge ressursgrunnlaget, da kan man høste ressurser i evighetsperspektiv.Utredning av sirkulærøkonomien i sjømatnæringenpublishedVersio
Kartlegging og overvåking av reinbeiter
Get PDFDenne rapporten beskriver arbeidet med satellittbasert kartlegging av vinterbeite i indre Finnmark. Prosjektet utgjør en ny oppdatering av reinbeitene på Finnmarksvidda og inngår i ”Overvåkingsprogrammet for Indre Finnmark”. Dette programmet ble initiert i 1998, med oppdateringer i 2005/2006, 2009/2010, 2013 og 2018. Overvåkingsprogrammet ble opprinnelig inndelt i to deloppdrag – et for registrering av bakkedata og et for kartlegging og arealberegning basert på satellitt data.Kartlegging og overvåking av reinbeiterpublishedVersio
Irreversible loss in marine ecosystem habitability after a temperature overshoot
Get PDFAnthropogenic warming of the oceans and associated deoxygenation are altering marine ecosystems. Current knowledge suggests these changes may be reversible on a centennial timescale at the ocean surface but irreversible at deeper depths even if global warming were to ameliorate. In contrast, the marine ecosystem’s response to these persistent changes remains poorly elucidated. Here we explore to what extent global warming may drive alterations in marine habitats by exploring the evolution of a metabolic index that captures marine organisms’ ecophysiological response to both temperature and oxygen changes, throughout an idealised ramp-up/ramp-down atmospheric carbon dioxide concentration and an overshoot scenarios. Using a multi-model approach; we find that changes in ocean temperature and oxygen drive a centuries-long irreversible loss in the habitable volume of the upper 1000 m of the world ocean. These results suggest that the combined effect of warming and deoxygenation will have profound and long-lasting impacts on the viability of marine ecosystems, well after global temperatures have peaked.publishedVersio
BVLOS UAV missions for vegetation mapping in maritime Antarctic
Get PDFPolar areas are among the regions where climate change occurs faster than on most of the other areas on Earth. To study the effects of climate change on vegetation, there is a need for knowledge on its current status and properties. Both classic field observation methods and remote sensing methods based on manned aircraft or satellite image analysis have limitations. These include high logistic operation costs, limited research areas, high safety risks, direct human impact, and insufficient resolution of satellite images. Fixed-wing unmanned aerial vehicle beyond the visual line of sight (UAV BVLOS) missions can bridge the scale gap between field-based observations and full-scale airborne or satellite surveys. In this study the two operations of the UAV BVLOS, at an altitude of 350 m ASL, have been successfully performed in Antarctic conditions. Maps of the vegetation of the western shore of Admiralty Bay (King George Island, South Shetlands, Western Antarctic) that included the Antarctic Specially Protected Area No. 128 (ASPA 128) were designed. The vegetation in the 7.5 km2 area was mapped in ultra-high resolution (<5 cm and DEM of 0.25 m GSD), and from the Normalized Difference Vegetation Index (NDVI), four broad vegetation units were extracted: “dense moss carpets” (covering 0.14 km2, 0.8% of ASPA 128), “Sanionia uncinata moss bed” (0.31 km2, 1.7% of ASPA 128), “Deschampsia antarctica grass meadow” (0.24 km2, 1.3% of ASPA 128), and “Deschampsia antarctica–Usnea antarctica heath” (1.66 km2, 9.4% of ASPA 128). Our results demonstrate that the presented UAV BVLOS–based surveys are time-effective (single flight lasting 2.5 h on a distance of 300 km) and cost-effective when compared to classical field-based observations and are less invasive for the ecosystem. Moreover, unmanned airborne vehicles significantly improve security, which is of particular interest in polar region research. Therefore, their development is highly recommended for monitoring areas in remote and fragile environments.publishedVersio
Slowdown of Antarctic Bottom Water export driven by climatic wind and sea-ice changes
Get PDFAntarctic Bottom Water (AABW) is pivotal for oceanic heat and carbon sequestrations on multidecadal to millennial timescales. The Weddell Sea contributes nearly a half of global AABW through Weddell Sea Deep Water and denser underlying Weddell Sea Bottom Water that form on the continental shelves via sea-ice production. Here we report an observed 30% reduction of Weddell Sea Bottom Water volume since 1992, with the largest decrease in the densest classes. This is probably driven by a multidecadal reduction in dense-water production over southern continental shelf associated with a >40% decline in the sea-ice formation rate. The ice production decrease is driven by northerly wind trend, related to a phase transition of the Interdecadal Pacific Oscillation since the early 1990s, superposed by Amundsen Sea Low intrinsic variability. These results reveal key influences on exported AABW to the Atlantic abyss and their sensitivity to large-scale, multidecadal climate variability.Slowdown of Antarctic Bottom Water export driven by climatic wind and sea-ice changespublishedVersio
The evolution of the Fram Strait sea ice volume export decomposed by age: estimating with parameter-optimized sea ice-ocean model outputs
Get PDFSea ice export through the Fram Strait is crucial in the dynamic evolution of Arctic sea ice and can further modulate Arctic sea ice mass balance as well as the ocean thermohaline circulation. In this study, based on outputs from a parameter-optimized and fully physical ocean–sea ice coupled model and sea ice age observation, we estimate sea ice volume (SIV) flux and its age evolution via the Fram Strait. The estimate of mean annual SIV flux is about 1605 315 km3 yr−1 without a significant trend for 1979–2021. Combining with sea ice age data, the variation of the sea ice age and its corresponding SIV flux are obtained for 1984–2020. The SIV flux of 1st-year ice significantly increases as expected, but it still contributes very little to the total flux in the 2010s with a proportion of 3.5%. SIV fluxes of different ages in multi-year ice present diverse variations. The proportions of 2nd-year ice and 3rd-year ice in the annual SIV flux show an extreme increase from 6.8% and 25.0% in the 1980s to 49.0% and 38.8% in the 2010s, respectively, while the proportions of 4th-year ice and 5th-year and older (5+ year) ice significantly decrease from 22.8% and 45.0% in the 1980s to 7.1% and 1.6% in the 2010s, respectively. Meanwhile, the prevailing age of annual volume export via Fram Strait shifts from 4th-year and 5+ year ice to 2nd-year and 3rd-year ice around 2007/2008. It is worth noticing that the variation in Fram Strait ice export modulates the variation in Arctic SIV prior to 2008, but the reverse is true after 2008, indicating a decreasing influence of Fram Strait SIV export on Artic SIV variability with decreasing sea ice age. The results are beneficial to promote the understanding of the evolution of Fram Strait SIV export under the warming Arctic.publishedVersio