Reinertsen Langehaug H*¹², Sagen H¹, Stallemo A¹, Uotila PJ³, Rautiainen L⁴, Olsen SM⁵, Devilliers M⁵, Yang S⁵, Storheim E¹
¹Nansen Environmental and Remote Sensing Center, Bergen, Norway, ²Bjerknes Centre for Climate Research, Bergen, Norway, ³University of Helsinki, Helsinki, Finland, ⁴Finnish Meteorological Institute, Helsinki, Finland, ⁵Danish Meteorological Institute, Copenhagen, Denmark
Global climate models (CMIP6 models) are the basis for future predictions and projections, but these models typically have large biases in their mean state of the Arctic Ocean. Considering a transect across the Arctic Ocean (100-700 m), we show that the model spread for temperature and salinity anomalies ramp up during the next two decades (2025-2045). The maximum model spread is reached in the following decade (2045-2055) with a standard deviation 10 times higher than in 1993-2010. The CMIP6 models agree that there will be warming, but do not agree on the degree of warming. We therefore test a new approach to find models with good performance. We split the analysis in two typical layers; namely the Halocline Layer (100-300 m) and the Atlantic Layer (300-700m). We assess how CMIP6 models represent the horizontal patterns of temperature and salinity in these layers in 1993-2010. Based on this, we find four models with relatively good performance. However, these models show different degree of warming over the next three decades, which may be a result of their different climate sensitivities. The model with the overall best performance shows a warming of about 0.4 °C and 0.7 °C in 2045-2055 (compared to 1993-2010) in the Halocline and Atlantic layer, respectively, when considering the low end ssp126 scenario. This means reduced warming but larger freshening than the multi-model mean (MMM).
Pedersen T*¹, Nascimento MC¹, Pedersen T¹, Mortensen S¹, Fransner F²
¹UiT The Arctic University of Norway, Tromsø, Norway, ²University of Bergen, Bergen, Norway
In this study we simulated effects of various future climate and fisheries scenarios using a dynamic mass balance food web model for the Barents Sea. Three climate scenarios (SSP 1-2.6, 2-4.5 and 5-8.5) and three levels of fisheries exploitation regimes (low, “business as usual”, and high fishing mortalities) were combined into nine scenarios running from 2023 to 2100 using an Ecosim model. The dynamic Ecosim model for the Barents Sea large marine ecosystem had high trophic resolution with 79 functional groups. We used time series of specific environmental drivers such as water temperature, ice coverage and phytoplankton primary production for each scenario from a physical model (NorESM withNemo NAA10km). Relationships for thermal performance and food-consumption rates were entered for each functional group in the model and coupled to the temperature time series to drive food-consumption in the scenarios. The Ecosim model outputs were analysed to test if scenario combinations of climate and fishery scenarios; i) affected ecosystem states and stability differently, ii) affected biomass and production of specific keystone and/or commercially important functional groups, and iii) had additive, synergistic or antagonistic effects on aggregated groups.
Muilwijk M*¹, Hattermann T¹, Martin T², Granskog M¹
¹Norwegian Polar Institute, Tromsø, Norway, ²GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
In recent decades, the Arctic has undergone extensive sea ice loss. The reduced ice cover affects the mechanical and thermodynamical coupling between the atmosphere and the ocean. One hypothesis suggests that a thinner and more mobile sea ice cover could lead to increased momentum transfer, resulting in an acceleration of upper Arctic Ocean circulation and enhanced vertical mixing. In general, sea ice protects the ocean from interaction with the atmosphere, and a shrinking ice cover implies a more direct transfer of momentum. However, previous modeling studies have demonstrated that seasonality plays a crucial role, and at times, more open water can lead to a decrease in momentum transfer due to the greater drag provided by the ice. Consequently, it remains uncertain whether the future sea ice cover will amplify or dampen the momentum transfer. To address this knowledge gap, we investigated future scenarios from an ensemble of CMIP6 models. We focused on examining the projected changes in momentum transfer in response to evolving sea ice and wind conditions, and how this depends on the formulation of drag. Our findings reveal that all models project an increase in ocean surface stress, primarily driven by a combination of intensified wind speeds and diminishing ice concentration. Although trends in wind speed are largest during late fall, the most substantial trends in ocean stress occur during winter, as reduced internal stress amplifies the impact of wind-driven changes.
Mańko M¹, Merchel M², Kwaśniewski S², Weydmann-Zwolicka A*¹
¹University of Gdańsk, Gdynia, Poland, ²Institute of Oceanology Polish Academy of Sciences, Sopot, Poland
Gelatinous zooplankton (GZ; pelagic cnidarians and ctenophores), are key players in marine ecosystems. Aside from their trophic importance, rapid reproductive cycles of GZ render their population size and structure tightly coupled to the environment, making them the ideal bioindicators for monitoring changes in the World’s Ocean. Unfortunately, due to their delicate nature and convoluted taxonomy, data on their distribution are scarce and of poor taxonomic resolution. To tackle this paucity of data, here we re-analyzed zooplankton time series (2003-2014) run by the Institute of Oceanology (Polish Academy of Sciences), to investigate the future of GZ communities in the European Arctic under the scenario of progressing Atlantification. Specifically, we tested 1) whether oceanic fronts modulate the spreading of boreal GZ in the Arctic? and 2) how will the most abundant GZ in the region, Aglantha digitale, respond to ongoing changes? We found that the two fronts (Arctic and Polar), which flank the main inflow of the Atlantic waters to the Arctic, constitute a semi-permeable barrier for GZ distribution, maintaining distinct GZ community across fronts. Further, we found evidence, that year after year, A. digitale reproduced earlier in the Fram Strait, and in anomalously warm period (2005-2007) may have even reproduced twice per season. Overall, these findings may be interpreted as hinting towards more gelatinous future of the European Arctic.
Heuzé C*¹
¹Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden
The Arctic Ocean is a challenge to model accurately. Its exchanges with the rest of the global ocean occur through narrow gateways. Ventilation within the Arctic requires a realistic continental shelf hydrography and slope, interaction with the sea ice and atmosphere, and preservation of dense overflows. At all depth levels, an accurate bathymetry is needed to properly represent the circulation. The uppermost layers depend on both surface heat fluxes and freshwater fluxes from rivers, glaciers, sea ice, and the atmosphere, while the deepest layers are impacted by geothermal heating. Despite this, many parameterisations and tuning processes applied in the Arctic are not representative of the polar regions. In addition, observations used to constrain Arctic models are often limited to the summer season, ice-free regions, or upper ocean. Therefore, unsurprisingly, the coarse-resolution CMIP-type models are highly inaccurate in the Arctic Ocean. In this presentation, I will provide a non-exhaustive list of biases in Arctic Ocean water mass representation and circulation in CMIP6 models, with a specific focus on how these biases impact our ability to accurately project future Arctic Ocean and global changes. Key directions for improving the Arctic Ocean in climate models will be discussed, along with new results from the ”future Arctic in CMIP6” workshop to be held this September in Bergen.
Havermans C*¹, Dischereit A¹, Murray A¹, Pantiukhin D¹
¹Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
Gelatinous zooplankton are major drivers of ecosystem changes. Increases in biomass or “jellification” have been observed in several marine ecosystems, causing, amongst other factors, major fishery collapses. For the Arctic region, accurate diversity and abundance data on jellies are virtually non-existent, impeding our ability to detect impacts of a similar magnitude. We study current and future species distributions of dominant Arctic jellyfish under a growing influence of Atlantic waters. To do so, we combine net catches with environmental DNA and optical video systems to provide new information on the drivers of jellyfish distributions in Arctic environments. On these and public datasets, we apply species distribution models to understand species and community patterns and predict changes under climate-change scenarios. Based on predictive modelling, we project an Arctic “jellification” with range shifts of major Atlantic species into the Arctic Ocean on the pan-Arctic scale, and an increase of regional jellyfish abundances. By means of molecular diet studies, we reveal the importance of jellyfish as prey based on molecular diet studies of predator species such as fish and zooplankton predators. Finally, by investigating the species richness, abundances, and trophic role of jellyfish in fjords in which the influence of Atlantic water differs, we set a baseline to detect potential range shifts and predict the impact of jellyfish on local food webs in an Atlantified Arctic.
Gou R*¹, Lohmann G², Wu L¹
¹Ocean University of China, Qingdao, China, ²Alfred Wegener Institute, Bremerhaven, Germany
The Arctic is warming faster than any other oceans, a phenomenon known as Arctic amplification that has far-reaching implications for global climate. In contrast, the Southern Ocean (SO) and Antarctica have cooled in recent decades. The projection of these regions under global warming exhibits non-negligible model spread. Here we show that under a strong warming scenario from the mid-20th to the end of the 21st century, comparing a modern high-resolution climate model with a low-resolution model version, the warming in the Arctic is 1.5 °C greater and the warming of SO and Antarctica is 1 °C less. By a conceptual model, we attribute the changed polar warming to polar marine extremes, which are largely unknown. The marine heat waves (MHWs) in the Arctic and SO are twice as strong in the high-resolution model version, with the increasing intensity of MHWs in the Arctic accompanied by a large decrease in sea ice. The much stronger MHWs in the high-resolution model are caused by two orders of magnitude more turbulent energy in the ocean. They are less correlated with ocean stratification than those in the low-resolution models. We conclude that the Arctic amplification and MHWs are underestimated by the current generation of climate models with low resolution, while the SO and Antarctica warming is overestimated. Our eddy- and storm-resolving model is expected to open new possibilities for how the system responds to human activities in a high-CO₂ world by assessing the impact on past and future climate and environmental extremes.
Dupont N*¹, Durant JM¹, Langangen ع, Stige LC¹²
¹University of Oslo, Oslo, Norway, ²Norwegian Veterinary Institute, Ås, Norway
Arctic marine areas are facing rapid abiotic changes with decrease of seasonal sea-ice cover and increased sea temperature. The changing abiotic environment has several ecological consequences: changes in the population dynamics of sea-ice associated species and increased presence of sub-arctic generalist marine predator species in the Arctic area, i.e., borealization. In the Barents Sea ecosystem, two key fish species, capelin (Mallotus villosus) and polar cod (Boreogadus saida), link sub-Arctic and Arctic food-webs through shared preys and predators. Decrease in sea-ice has been predicted to negatively affect the population of polar cod. In addition, increase in the presence of sub-arctic marine predators in the Arctic part of the Barents Sea ecosystem may affect consumption rates of polar cod moderated by the condition of capelin stock. The consequences on Arctic marine ecosystem of both changes remain to be fully investigated. We hypothesize that both abiotic changes and borealization of the Barents Sea will significantly affect the stock of polar cod. To test this hypothesis, we combined recently developed statistical models: two age-resolved state-space models, for capelin and for polar cod, and a threshold model for predation rates in an integrated ecosystem state-space model for the Barents Sea food web. This approach allows us to predict the effect on the Barents Sea Arctic food-web of abrupt change(s), i.e., capelin stock collapse, in a rapidly changing environment.
Zhulay I*¹², Bluhm BA², Åström E²³, Kristoffersen Y⁴, Hall JK⁵
¹Centre for Deep-Sea Research, University of Bergen, Bergen, Norway, ²UiT The Arctic University of Norway, Tromsø, Norway, ³Institute of Marine Research, Swedish University of Agricultural Sciences, Lysekil, Sweden, ⁴Institute for Geosciences, University of Bergen, Bergen, Norway, ⁵Geological Survey of Israel, Jerusalem, Israel
Sea ice decline makes the central Arctic Ocean (CAO) increasingly accessible, sparking interest in potential seafloor resource use. The Fram-2014/15 ice drift expedition provided the unprecedented opportunity to obtain seafloor imagery at the Lomonosov Ridge and Morris Jessup Rise (84-89 °N). We investigated the acquired material to fill critical knowledge gaps of the epibenthic life at these deep Arctic ridges (800-2650 m). The megafaunal inventory revealed communities similar to those observed in other Arctic deep-sea regions – the Chukchi Borderland, Fram Strait, and Nansen and Amundsen Basins. Arthropods (amphipods and mysids) and echinoderms (Pourtalesia jeffreysi, Bathycrinus carpenterii, ophiuroids, and Kolga hyalina) showed a high occurrence across the study area. Most taxa were of Atlantic-boreal biogeographic affinity. Fish included the Glacial eelpout (Lycodes frigidus) and the currently known northernmost observation of Arctic rockling (Gaidropsarus argentatus) (86 °N). In addition, one station indicated seafloor seep activity with microbial mats and aggregation of large sponges. These observations share a high resemblance to previously described seep-sites in adjacent areas as well as nearby central Arctic Karasik seamount. This study expands the current knowledge of deep CAO ecology and supports the emerging picture of much higher habitat diversity in the Arctic deep-sea than previously appreciated.
Randelhoff A*¹, Koenig Z², Muilwijk M², Dodd P², Chierici M³
¹Akvaplan-niva AS, Tromsø, Norway, ²Norwegian Polar Institute, Tromsø, Norway, ³Institute of Marine Research, Tromsø, Norway
Turbulent mixing in the Arctic Ocean is undergoing drastic changes. Some evidence is starting to appear for both increases in internal wave energy and basin-scale erosion of double-diffusive staircases, but the consequences for turbulent and diffusive mixing on a larger scale remain difficult to quantify. Here, we present ongoing work on measurements from the 2021 and 2022 R/V Kronprins Haakon missions to the central Arctic Ocean's Amundsen and Nansen basins, where we sampled hydrography, turbulent microstructure, and inorganic nutrient concentrations. Dissipation of turbulent kinetic energy was reliably sampled only in the upper approx. 50 m of the water column, whereas deeper in the water column, background dissipation levels were usually below the instrument noise floor (O(10⁻⁹ W kg⁻¹)). Accordingly, we found double-diffusive staircases occurring both in the Amundsen and Nansen basins, whose presence we used to constrain background turbulent dissipation to at most O(10⁻¹⁰ W kg⁻¹). Upward double-diffusive heat fluxes are hence at least as important as turbulent ones at around O(0.1-1 W m⁻²), and slightly larger in the Nansen than the Amundsen Basin. Upward turbulent nitrate fluxes both across the surface layer base are in line with previous estimates made during winter, suggesting that wind-driven mixing does not regularly penetrate the surface stratification enough to affect mixed layer nutrient inventories. Double-diffusive nitrate fluxes likely did not play a role, based on a tentative calculation using salt fluxes across double-diffusive steps. The modest fluxes presented here do so far not show an enhanced turbulence regime during our observations and may suggest a continued tight control of large-scale stratification on upward heat and nutrient fluxes.
Lange BA*¹², Cimoli E³, Johnsen G⁴, Campbell K⁵, Osanen J⁴⁵, Anhaus P⁶, Summers N⁴, Granskog M², Katlein C⁶, Luceer V², Matero I⁷, Nicolaus M⁶
¹Norwegian Geotechnical Institute, Oslo, Norway, ²Norwegian Polar Institute, Tromsø, Norway, ³Institute for Marine and Antarctic Studies, College of Sciences and Engineering, University of Tasmania, Hobart, Australia, ⁴Norwegian University of Science and Technology, Trondheim, Norway, ⁵UiT The Arctic University of Norway, Tromsø, Norway, ⁶Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany, ⁷SIOS-KC, Svalbard Integrated Arctic Earth Observing System Knowledge Centre, Longyearbyen, Norway
The impact of a rapidly shifting sea-ice cover on climate, ecosystem processes and biophysical habitat properties is not yet fully understood due to a lack of spatially and temporally representative observations within the Central Arctic Ocean. Sea ice coring is a standard sampling method in sea ice research, however, to overcome spatio-temporal sampling limitations, non-invasive methods are needed. Underwater hyperspectral imagery (UHI) is an emerging technology, which enables non-invasive biophysical characterization of the sea ice bottom. Here we will present a comprehensive dataset of UHI sea ice surveys from the central Arctic Ocean covering nearly the full algal growth season from May to Oct. Surveys were conducted with a ROV-mounted UHI, enabling survey lengths 50-200 meters with < 1 cm spatial resolution. UHI surveys were conducted during five cruises: MOSAiC (June-July 2020), Kronprins Haakon (KPH, May 2021, July-Aug 2022), Odin (May-June 2023), Polarstern (Aug-Oct 2023). UHI surveys included a one-month time series of the same ice. Overall, several ice types were surveyed including both MYI and FYI, ridged ice, and thin new ice. We surveyed a range of snow-covered and advanced melt ice conditions. Algal communities also varied from more typical bottom ice algal communities to algal aggregates and Melosira forests. We present some preliminary results from the ROV-UHI surveys and provide an overview of the regions, ice types, algal types and sea conditions surveyed.
Koenig Z*¹, Gallagher M², Lac J³, Heuze C⁴, Schaffer J⁵
¹UiT The Arctic University of Norway, Tromsø, Norway, ²NOAA, Boulder, USA, ³Laboratoire de Meteorologie Dynamique, Paris, France, ⁴University of Gothenburg, Gothenburg, Sweden, ⁵Previously Alfred Wegener Institute, Bremerhaven, Germany
North of Greenland is a region historically characterized by multi-year sea and high concentration of sea ice. At some occasions however, the sea ice concentration North of Greenland decreases and a polynya can open, in both winter and summer. In August 2020, the polynya North of Greenland opened. This area of open water up to 88 °N was used to relocate Polarstern northward at the beginning of leg 5 of MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate), but also provided a unique opportunity to study this extremely undersampled region. Combining observations from the ship, in particular expendable hydrographic profiling probes (XCTDs), and atmospheric reanalysis, we investigate the dynamics of the opening of the polynya and its influence on the water column. The opening of the polynya is most likely caused by southerly winds lasting for nearly 10 days, from July 26 to August 4. In the polynya, surface waters are warmer than the freezing point, and the mixed layer is about 40 m deep. Hydrographic characteristics below the mixed layer (and above 200 m) indicate contributions from waters of Atlantic origin and glacial meltwater. Currently, we are investigating the impact of the polynya on the different such as heat fluxes between the atmosphere and the ocean.
Williams B*¹, Brown K², Rotermund L³, Bluhm B⁴, Danielson S⁵, Dempsey M¹, Vagle S¹, Carmack E¹
¹Fisheries and Oceans Canada, Sidney, Canada, ²University of Manitoba, Winnipeg, Canada, ³Dalhousie University, Halifax, Canada, ⁴UiT The Arctic University of Norway, Tromsø, Norway, ⁵University of Alaska Fairbanks, Fairbanks, United States of America
The Kitikmeot Sea of the southern Canadian Arctic Archipelago lies within the heart of the southern Northwest Passage and is home to five Indigenous communities. It is unique in the pan-Arctic system due to: (1) shallow bounding sills that are less than 30 m deep; (2) primary nutrient and salt supplies delivered over the sills from the Canada Basin; and (3) massive freshwater input from a watershed five-times its size. An estuarine-like circulation is maintained at the sills where exiting freshwater restricts replenishing inflow of salty, nutrient-rich oceanic water, and leads to a low-productivity ecosystem in the region. Observations from 1999-2019 suggest the Kitikmeot Sea functions as a nested estuary where exchanges of fresh and salt water are controlled at shallow interior and bounding sills. A system of four interacting estuaries (Coronation Gulf, Bathurst Inlet, Queen Maud Gulf, and Chantry Inlet) set up the predominant circulation, within which winds, tides, and boundary circulation control local conditions. We further propose a conceptual model of marine ecosystem function, one that supports an abundance of char and seals as top predators instead of the larger polar bears and whales found elsewhere in the Canadian Arctic Archipelago. Since climate change will impact critical social-ecological functions of the Kitikmeot Sea, understanding of connections within, and external to, this region is needed for its communities to prepare for an uncertain future.
Weber C*¹², Juma GA¹², Meunier CL¹, Boersma M¹²
¹Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Helgoland, Germany, ²University of Bremen, Bremen, Germany
Higher temperatures in the Arctic are expected to increase permafrost soil thawing, leading to a larger discharge of muddy, carbon-rich water into coastal areas. Higher turbidity and increased levels of dissolved organic carbon (DOC) in nearshore ecosystems are likely to affect the biomass and community structure of phytoplankton and bacteria that form the base of the marine food web. Higher turbidity will reduce light intensity, thereby directly impacting phytoplankton growth. With DOC being an important carbon source for bacteria, increasing DOC levels might promote bacterial growth. Changes in bacteria and phytoplankton communities can have significant consequences for the marine food web and ultimately affect the functioning of coastal Arctic ecosystems. We conducted a mesocosm experiment to determine the relative importance of light reduction and DOC levels in altering phytoplankton to bacterial biomass ratios and phytoplankton community structure. Natural plankton communities from Herschel Island (Beaufort Sea, Canada) were exposed to four different treatments: 1) a control treatment, 2) a treatment with addition of a clear carbon solution (no light attenuation), 3) a treatment with addition of light-reducing pigment (no carbon addition), 4) a treatment with addition of natural thaw slump material (light attenuation and carbon addition). Preliminary results indicate DOC impacting growth of planktonic communities more than light reduction.
Gjerluff Ager T*¹, Krause-Jensen D¹, Sejr M¹, Duarte CM², Mankoff KD³, Friis Møller E⁴, Boertmann D⁴, Schourup-Kristensen V⁴
¹Aarhus University, Aarhus, Denmark, ²King Abdullah University of Science and Technology, Saudi Arabia, ³NASA GISS, New York, USA, ⁴University Aarhus, Roskilde, Denmark
The Greenland coastline, spanning 24° latitude, harbors diverse marine ecosystems. Although there is a growing understanding of changes in Greenland marine ecosystems in response to climate change, the vast differences between regions and synergetic effects of different physical drivers are rarely addressed. Our study investigates regional trends in ecologically relevant physical drivers along the Greenland coastline and their impacts on marine organisms. Six subregions are delineated to identify spatial variations and interactions among drivers. We review available time series on changes in Greenland's marine communities and compare them with expectations based on synthesized physical driver changes. Our results identified strong regional differences in relevant drivers and the number of interacting drivers. Hotspots of climate change were identified between 67 – 76 °N, which were affected by large changes in the sea ice regime, run off and sea surface temperatures. We identified a limited number of consistent trends in biological communities from the literature. These findings emphasize the importance of considering synergistic effects of physical drivers when studying responses to climate change in Arctic environments. Greenland remains heavily understudied, although monitoring programs cover key areas. Our research contributes to comprehending the ecological dynamics in this critical region.
Faria da Costa J*¹, Lourenço P¹², Santos I¹², Semedo M¹, Pascoal F¹, Martins B³, Canário J³, Magalhães C¹²
¹Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, Portugal, ²FCUP Faculty of Sciences of the University of Porto, Porto, Portugal, ³Centro de Química Estrutural, Institute of Molecular Sciences and Department of Chemical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
The Arctic permafrost is facing massive thawing due to global warming, leading to an increased mobility of historically accumulated contaminants, such as mercury (Hg). By the action of specific microorganisms present in these environments, Hg can be methylated to methylmercury (MMHg), a neurotoxin that bioaccumulates and biomagnifies in the food web to concentrations that result in severe adverse effects for humans and wildlife. Environmental MMHg concentration is also determined by the rate of its degradation, which can occur through the action of MMHg-resistant microorganisms employing a Hg-resistance (mer) system. Simultaneous methylation and demethylation reactions have been studied in diverse environmental systems over the years, but information regarding its characterization in permafrost thaw lakes remains to be completely known. In this work we aim to characterize the microbial communities involved in Hg-cycle pathways of two thermokarst lakes in the Canadian Subarctic, focusing on microorganisms carrying specific methylation and demethylation genes. Environmental DNA (eDNA) was extracted from sediments collected in 2022, and the presence of genes involved in methylation (hgcA and hgcB) and demethylation (merA and merB) mechanisms were analyzed through molecular techniques and metagenomic shotgun sequencing. We identified several bacterial and archaeal groups involved the different pathways of the Hg-cycle, with different community structures between the two locations. These results are improving our understanding of the Hg-cycle pathways and its prokaryotic communities, important to evaluate the impacts of permafrost thawing on Arctic ecology, ecosystem services and human health.
Al-Habahbeh AK*¹, Sejr M², Bluhm BA¹, Primicerio R¹
¹UiT The Arctic University of Norway, Tromsø, Norway, ²Aarhus University, Aarhus, Denmark
Extensive fjord systems are important areas of land-to-sea exchange, in parts of the Arctic. In Northeast Greenland, reduced sea-ice cover and increased run-off from the Greenland ice sheet are altering the physical environment, with consequences for the marine ecosystem. Epibenthic organisms in the Arctic tend to live long and can reflect long-term change, yet time series here are lacking. ROV derived under-water imagery from 2003-2010 and 2021-2022 offered a temporal comparison of epibenthic communities along three transects from 20-60 m depth in Young Sound, NE Greenland, to test if climate warming has altered the community structure. Preliminary results indicate the persistent dominance, though altered abundance, of brittle stars and bivalves, and the sudden appearance of a previously unrecorded large ascidian, in the most recent years. This indicates that change is already occurring in this fjord, which is concerning since the coast of Northeast Greenland is less affected by increasing ocean temperatures compared to the inflow regions.
Lasabuda APE*¹²³, Shephard G¹, Faleide JI¹, Salles T², Müller D²
¹University of Oslo, Norway, ²The University of Sydney, Australia, ³UiT The Arctic University of Norway, Norway
The Barents Seaway represents an important marine connection between the Atlantic and Arctic oceans. However, how and when precisely the Barents Seaway formed are not very well understood being overshadowed by its neighbor, the Fram Strait Gateway. The Bravo (Barents Sea Evolution) project will address this issue and aims at reconstructing the Barents Seaway paleobathymetry in the Cenozoic. The key challenge is to quantify the spatial distribution and temporal evolution of km-scale vertical movement of Cenozoic uplift and erosion due to glaciations and pre-glacial tectonism. BRAVO approach requires a comprehensive analysis of off-shelf sediment estimation, lithospheric strength, and other mantle-related processes in order to produce a reliable model. BRAVO will use extensive seismic and well data, and utilize numerical modelling technique using pyGPlates software. BRAVO will also test the paleobathymetry reconstructions by simulating the corresponding sediment source-to-sink in the Cenozoic using pyBadlands, an open-source codes for sediment transport, erosion and depositional processes. BRAVO is a Marie Skłodowska-Curie Actions (MSCA) project funded by the European Union’s Horizon Europe and the Research Council of Norway (2023-2026).
Renner AHH*¹, Bailey A², Reigstad M³, Sundfjord A², Chierici M¹, Jones E¹
¹Institute of Marine Research, Tromsø, Norway, ²Norwegian Polar Institute, Tromsø, Norway, ³UiT The Arctic University of Norway, Tromsø, Norway
Changing Atlantic Water (AW) inflow promotes sea ice decline and borealisation of marine ecosystems and affects primary production in the Eurasian Arctic Ocean. North of Svalbard, the AW inflow dominates oceanographic conditions along the shelf break, bringing in heat, salt, and nutrients. However, interaction with sea ice and Polar Surface Water determines nutrient supply to the euphotic layer. We investigate the role of sea ice for hydrography, nutrients and seasonal dynamics of chl a, based on a combination of satellite data and in-situ measurements from a transect across the AW inflow at 31 °E, 81.5 °N, visited regularly since 2012. Large interannual variability in hydrography, nutrients and chl a indicates varying levels of nutrient drawdown by primary producers over summer. Sea ice conditions impact surface stratification, light availability, and wind-driven mixing, with a strong potential for steering chl a concentration over the productive season. In early winter, nutrient re-supply through vertical mixing varied in efficiency, again related to sea ice conditions. The re-supply elevated nutrient levels sufficiently for primary production but likely happened too late in the season when high-latitude light levels limited potential autumn blooms. Such multidisciplinary observations are key to gain insight into the interplay between physical, chemical, and biological drivers and to understand ongoing and future changes, especially at this entrance to the central Arctic Ocean.
Nikolopoulos A*¹, Sundfjord A¹, Reigstad M², Lee C³, Polyakov I⁴, Whitmore L⁴, Yang E-J⁵, Jung J⁵, Grebmeier J⁶
¹Norwegian Polar Institute, Tromsø, Norway, ²UiT The Arctic University of Norway, Tromsø, Norway, ³University of Washington, Seattle, USA, ⁴University of Alaska Fairbanks, ⁵Fairbanks, USA, Korean Polar Research Institute, Incheon, Korea, ⁶University of Maryland Center for Environmental Science, Solomons, USA
The Arctic climate system is in great distress, warming faster than the rest of the world and transforming more rapidly than previously anticipated. Sustained, focused, and harmonized multidisciplinary information is needed to fill knowledge gaps and evaluate the climate change impacts on the complex Arctic marine system. Since 2010, the Distributed Biological Observatory (DBO) has functioned as a “detection array” for ecosystem changes and trends in the Pacific sector of the Arctic Ocean. This long-term, multi-disciplinary initiative builds on active involvement of scientists with the main aim to systematically increase the scientific documentation of how biological systems are transforming with the environmental change. The DBO sampling concept is currently being expanded to other portions of the Arctic, including Davis Strait and Baffin Bay, the Atlantic Arctic gateway area, and the East Siberian Sea. Through increased collaboration and joint scientific objectives and methods, findings from such regional key areas can leverage to pan-Arctic perspectives and improve our understanding of the entire Arctic Ocean. Here, we present the latest developments in the process of integrating the regional networks into a pan-Arctic framework and how our efforts connect to other parallel processes aiming to strengthen the pan-Arctic observational system. A major part of these collaborative efforts is currently facilitated by the EU Horizon project Arctic PASSION.
Marsden L*¹, Schneider O², Dekhtyarev V³
¹University Centre in Svalbard (UNIS), Longyearbyen, Norway, ²Norwegian Polar Institute, Tromsø, Norway, ³Norwegian Polar Institute, Tromsø, Norway
A new version of the Nansen Legacy metadata logging system has been developed for use on cruises beyond the Nansen Legacy project. The aim is to simplify the process for scientists and reduce the workload, whilst improving consistency across cruises and projects. This will be achieved through 1) the development of a user interface through which all samples and sampling events can be easily logged into a single PostgreSQL metadata catalogue hosted onboard, 2) semi-automatic logging of most sampling activities and Niskin bottles thanks to integration with the onboard ‘Toktlogger’ and the .btl files, 3) reduction of copy-paste errors by allowing the user to simply click on which sampling activity they want to log samples for, 4) in situ propagation of metadata from ‘parents’ (e.g. sampling activities) to ‘child’ samples, 5) removing cases where users have to unnecessarily provide the same information multiple times. It will remain possible to log metadata in spreadsheet templates initially if desired, and users should be able to download whatever metadata they want with a few clicks of their mouse. The logging system will be developed and managed by a multi-institutional team so that it can be used by scientists for years to come. We hope that you will use this logging system, and we welcome all feedback and suggestions.
Margevich A*¹, Timmermans M-L¹, Danielson S²
¹Yale University, New Haven, CT, United States, ²University of Alaska Fairbanks, Fairbanks, AK, United States
The inflow of relatively warm and fresh Pacific Ocean waters through Bering Strait to the Arctic Ocean influences stratification as well as seasonal sea ice retreat. Mooring observations in Bering Strait show that over the last few decades, transport has increased at ~0.01 Sv/yr. Winds over the region have not increased comparably, suggesting that local winds are not the only factor influencing transport. The complex coastline and bathymetry in the vicinity of the strait, highly seasonally dependent buoyancy fluxes and buoyancy gradients, as well as large-scale atmospheric and ocean circulation patterns in the surrounding regions likely all influence transport through Bering Strait. We analyze Dynamic Ocean Topography (DOT) to investigate the fundamental dynamics governing flow through Bering Strait. Our findings support that flow through the strait is approximately in geostrophic balance such that the across strait DOT slope is proportional to transport through the strait. We explore how this across-strait DOT slope relates to different mechanisms, such as local surface stress and inter-basin DOT differences, to determine how these processes influence transport and ultimately gain a better understanding of how Bering Strait transport will be affected by a warming climate.
Lukasik M*¹, Kotwicki L¹, Cochrane S²
¹ Institute of Oceanology Polish Academy of Sciences (IOPAN), Sopot, Poland, ²Akvaplan-niva, Tromsø, Norway
The Arctic region has been well recognized as a place where the impact of climate change is noticed quickly. Ongoing melting ice cover and glaciers change the Arctic’s landscape. Tidal flats consider areas with muddy/sandy surfaces that are periodically submerged and exposed to the air by changing water levels. The slope is slight, meaning the seabed area exposed during the low tide is considerable. One of the main goals of this research is to study how tidal flats can react to climate change. The synergy between seabed morphology and climatic influences has remarkable importance on living conditions. Water level change, ice cover, temperature and salinity change, and water dynamics in the shoreline zones as well as proximity to the open sea and freshwater inflow, are under observation. To know this habitat better, the samples are collected to make the following analyse: qualitative and quantitative macrofauna, meiofauna, and microfauna, eDNA, sediment chemistry, sediment chlorophyll, LOI granulometry. Samples are obtained from 2 tidal flats in the Svalbard archipelago and 3 tidal flats in the Tromsø area. The study’s first results indicate a high heterogeneity of the habitat and biological assemblages depending on the location. Moreover, it has been found that in all Arctic tidal flats, the most significant stressor for life is the long-term ice cover. Based on accessible sea water level models, it seems that with melting ice cover, this habitat can be drawn in and change the character and role in the ecosystem.
Hatta M*¹², Davis M², Grand M³, Jarda R², Measures C²
¹Institute of Arctic Climate and Environment Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan, ²University of Hawaii, Honolulu, Hawaii, USA, ³Moss Landing Marine Laboratories, Moss Landing, California, USA
Currently, our understanding of ocean biogeochemical data is limited needing increased coverage in both space and time. Our ability to obtain a large number of samples in the ocean is limited by complex analytical protocols, that are utilized both at sea and ashore. Areas like the Arctic Ocean are subject to rapidly changing freshwater inputs from increasing sea ice melt and rivers, which impact the surface ocean. Since the Arctic Ocean is surrounded by vast continental shelves, the geochemical transport of material from the continental boundary to the Arctic interior will also change with climate making it more important to understand the geochemical cycles in the Arctic. In our recent work [Hatta et al, 2021; 2023], we have developed methodologies for nutrient analysis using a miniaturized, automated, microfluidic analyzer. Through their robustness, minimal reagent use, and computer-controlled manipulations they meet the prerequisites for unattended operation. These methods use distilled water standards but eliminate the schlieren effect thus curbing matrix effects during seawater analysis. These newly developed methods can also be used to determine freshwater samples and pore waters. Furthermore, using their highly precise syringe pump system, these methods are capable of producing an automated standard curve from a single distilled water standard solution. We are now trying to adapt this technique to the shipboard trace metal analysis.
Flo S*¹², Svensen C², Præbel K²³, Bluhm B², Vader A¹
¹The University Centre in Svalbard, Longyearbyen, Norway, ²UiT The Arctic University of Norway, Tromsø, Norway, ³Inland Norway University of Applied Sciences, Elverum, Norway
Although the small size-fraction of copepods (<1 mm) are important constituents of the Arctic food-web, their trophic interactions remain largely unexplored, partly due to methodological limitations. We here characterize the prey of the cyclopoid Oithona similis, harpacticoid Microsetella norvegica and calanoid Microcalanus spp. from the Arctic Barents Sea and Nansen Basin in March, April-May, August, and December using brute force prey metabarcoding of the 18S rRNA gene. Of the prey identified, chaetognaths were the most consistently identified taxa and composed 47% of all prey reads. Reads from diatoms (16%), dinoflagellates (11%) and urochordates (8%) were likewise abundant, but these taxa were more prevalent during specific seasons. Diatoms composed 43% of prey reads in April-May, dinoflagellates 15% in December and 17% in March, and urochordates 20% in August. Although some species differences were also discernible, we show that the dietary composition varied more among seasons than among species. This was observed despite the taxonomic and behavioural differences that distinguish the ambush-predator O. similis, chemosensoric particle-chaser M. norvegica and current-feeding Microcalanus spp. The results thus indicate that dietary plasticity is common in small Arctic copepods, regardless of their behaviours or strategies for finding food. We moreover hypothesize that such plasticity is an important adaptation in systems where prey availability is highly seasonal.
Dinevik H*¹², Keck Al-Hababeh A¹, Gulliksen B¹, Bluhm B¹
¹UiT The Arctic University of Norway, Tromsø, Norway, ²Stockholm University, Stockholm, Sweden
Information about the longevity of marine organisms is essential to understand ecological succession, stability, competition, and the ability of ecological systems to recover from disturbances caused by pollution and climate change. Longevity-information is primarily known for calcareous taxa and those containing hard structures but lacking in soft-bodied taxa. This study presents data on longevity for sea anemones based on underwater photography at two (Svalbard, northern Norway) hard bottom areas over 34-40 years. Individual Urticina sp. (likely eques) was followed 28 and 38 subsequent years in northern Norway and Svalbard, respectively, indicating a maximum longevity of ≥38 years. Metridium senile individuals, only found in northern Norway, were observed in up to 28 subsequent years. Despite the higher maximum persistence at Svalbard, 68% there were only found in a single year and few for >10 years; we suspect physical disturbance (ice scouring, rock movement) as the cause of the stronger dynamic at this horizontal bottom site. In contrast, at the vertical rock wall in northern Norway more (28%) individuals persisted for >10 years. The results indicate that the stability of sea anemone populations is dependent on angle of the substrate, and that individuals can become quite old. Sea anemones can be dominant at rocky bottom communities in northern areas, hence knowledge about their longevity is important to understand the ecological dynamics of such communities.
Campbell K¹*, McKay R¹, Koenig Z¹, Laber C¹, Osanen J², Itkin P¹ and participants of the 2023 BREATHE Field School
¹UiT The Arctic University of Norway, Tromsø, Norway, ²Norwegian Technical University (NTNU), Trondheim, Norway
In the spring of 2023, twenty early career researchers drifted with a sea ice floe north of Svalbard to study its physical-biogeochemical properties and the dynamics of the underlying water column. Participants were trained by researchers from UiT The Arctic University of Norway on related topics as part of a field school, and they collected a comprehensive dataset that characterised the floe over the ten-day drift. Here we present an overview of this successful training event and show first data from the fieldwork, which highlight the spatiotemporal variability of the microbiological communities present within the ice and their link with physical-chemical growth conditions. The field school represents an important contribution to the BREATHE (Bottom-sea ice Respiration and nutrient Exchanges Assessed for THE Arctic) and SIDRiFT (Sea ice deformation and snow for an Arctic in Transition) research projects, funded by the Norwegian Research Council. It is the first drift study conducted from the Norwegian research vessel Kronprins Haakon.
Calvet N*¹, Yoccoz N¹, Bluhm B¹, Altenburger A²
¹UiT The Arctic University of Norway, Tromsø, Norway, ²The Arctic University Museum of Norway, UiT The Arctic University of Norway, Tromsø, Norway
The Barents Sea, a shelf sea in the European Arctic, is influenced by warm North Atlantic and cold Arctic waters. Over the last century, its mean temperature has increased by 1.5 °C above and 0.5-0.8 °C below 60 m, a disproportionately high warming compared to other ocean areas. It is expected and documented only for a few taxonomic groups of marine organisms, that ocean warming has led to and will lead to changes in distribution. We used data on invertebrates mediated by the Global Biodiversity Information Facility to characterize species distributions and their shift over more than a hundred years. The data were separated into five periods covering 1861-2010 and three geographical regions. Over time distribution of invertebrates has changed in different ways. Overall, 71% of 364 species investigated with a log-linear model presented a change in occurrence numbers per region in at least one period. For the north-eastern and central Barents Sea, a turning point was 1980, after which a drastic change in taxon occurrence patterns was observed. Distributions in the southern area consistently changed through time. Examples of the temporal trajectory of distribution change for a few individual species comprising Arctic and boreal affinities are discussed. To conclude, in the Barents Sea’s history, the distribution of invertebrates has shifted, most likely due to climate changes.
Assmann K*¹, Ingvaldsen R², Polyakov I³⁴, Husson B², Fossheim M¹, Primicerio R¹⁵
¹Institute of Marine Research, Tromsø, Norway, ²Institute of Marine Research, Bergen, Norway, ³International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, USA, ⁴College of Natural Science & Mathematics, University of Alaska Fairbanks, Fairbanks, USA, ⁵UiT The Arctic University of Norway, Tromsø, Norway
The Barents Sea forms an important interface between the Atlantic and Arctic Ocean regimes. Part of the main circulation pathway, the northeastern Barents Sea has experienced rapid Atlantification becoming ice-free in winter, warming, and losing stratification. Recent changes in the Barents Sea have been well documented, but their influence on the effects of Atlantification in the Eastern Eurasian Basin (EEB), like the erosion of the cold halocline layer (CHL), remain unclear. In the EEB this has mainly been linked to a warmer Atlantic Water (AW) inflow north of Svalbard and enhanced winter mixing. However, using hydrographic observations we show that the salinity of the CHL in the EEB after 1999 is strongly influenced by salinity variations on the northeastern Barents Sea shelf. We argue that the changes on the Barents Shelf conspire with the fact that the Kara Sea now has a similar upper ocean structure to the northeastern Barents Sea due to the loss of a summer sea ice cover to allow the salinity variability of the through-flowing AW to survive into the CHL. Furthermore, stronger influence of the Barents Sea throughflow may also bring with it sub-arctic or boreal species into the Arctic. We use the available data base to speculate that the expansion of the Atlantic-Arctic domain into the Kara Sea has already led to the expansion of boreal species towards the Arctic Ocean. Our results highlight the importance of the Barents Sea throughflow for the physical ice-ocean system in the EEB and for the pelagic ecosystem in the Arctic Basin.
Amargant Arumí M*¹, Gradinger R¹
¹UiT The Arctic University of Norway, Tromsø, Norway
As an Arctic inflow shelf, the Barents Sea (BS) is a highly dynamic and productive ecosystem. Changes in Atlantic Water heat transport and sea ice extent, thickness and phenology have altered the marine ecosystem in recent decades, modifying stratification regimes and consequently microbial access to nutrients and light. The combination of these physical factors, as well as biological interactions within the food web, determine the seasonal succession in primary production. In this study, the seasonality in sympagic and pelagic primary production (PP) was assessed by revisiting a cross-latitudinal transect in four distinct seasons: late summer and late autumn in 2019, and winter and spring in 2021. PP strongly increased from the polar night to the polar summer. In the autumn-winter months, sympagic and pelagic production were consistently low throughout the euphotic zone in all sampled locations. In spring, the highest levels of production were detected in a pelagic diatom bloom at the southernmost station, and a sea-ice algal bloom in the Marginal Ice Zone (MIZ). Simultaneously, an under-ice phytoplankton bloom and an advected North Atlantic bloom were found in the Northern BS. In summer, PP was closely associated with the MIZ in the northern section of the transect, where sea ice algae contributed highly to the regional production. In more southern stations, pelagic PP was found over larger depth ranges. These results provide insights into future regime changes in the Arctic.
Session chairs:
Marius Årthun (University of Bergen, Norway), Céline Heuzé (University of Gothenborg, Sweden), Martí Amargant Arumí (UiT The Arctic University of Norway, Norway), Natalie Summers (NTNU, Norway)
Session content:
Nowhere is climate change more evident than in the Arctic with an unprecedented loss of sea ice and warming at more than twice the global rate. A warmer and ice-free Arctic Ocean could have cascading effects on weather and climate over mid-latitudes, the Atlantic meridional overturning circulation, and marine ecosystems. A visible manifestation of Arctic climate change is the poleward penetration of warm Atlantic and Pacific waters and biota. This encroaching borealization of the Arctic Ocean represents an essential step towards a new Arctic climate state and ecosystem. All of these changes are rapid, complex, and little understood, as the Arctic Ocean is both poorly observed and difficult to model. Nevertheless, this session aims to provide some answers.
Session chairs:
Mats Granskog (Norwegian Polar Institute, Norway), Igor Polyakov (University of Alaska, Fairbanks, USA), Christine Gawinski (UiT The Arctic University of Norway, Norway)
Session content:
The central Arctic Ocean is experiencing rapid changes, primarily exemplified by the reduction in sea ice, which is caused by atmospheric and oceanic changes and accelerated by feedback processes. A prominent example of change is the borealization of the Arctic, affecting water column stability which is a key aspect of the functioning of the whole Arctic marine system. The ongoing changes have largely unknown consequences on polar marine biogeochemistry and ecosystem functioning in the deep Arctic basins. The lack of observations in this difficult-to-access region in part hampers a comprehensive assessment of the changes that have already occurred in the system, but also limits future predictability.
This session presents work focusing on the physical, biogeochemical, and ecological changes that have occurred in the central Arctic in recent decades.
Session chairs:
Paul Renaud (Akvaplan-niva, Norway), Zou Zou Kuzyk (University of Manitoba, Canada), Jakob Dörr (University of Bergen, Norway)
Session content:
Whereas many of the climate drivers of ecosystem change are shared across the Arctic, their ecosystem impacts are modulated by regional and local characteristics. Interior and outflow shelves differ from the Nansen Legacy study area, the northern Barents Sea, in their geomorphology, water mass characteristics, links with terrestrial and fresh-water systems, biotic communities, and how they are utilized by Arctic peoples. We aim to identify commonalities and differences in ecosystem response to climate change and other human impacts from the atmospheric, oceanic, geochemical, and ecological fields as well as the effect of climate changes on humans in Arctic coastal communities. Paleoceanographic studies and model projections will expand the temporal aspects of our studies, and insights gained can improve observational strategies in these regions of the Arctic. This session also contributes to exploring the linkages across domains such that we can better integrate our regional understanding within a context of pan-Arctic change.
Session chairs:
Randi B. Ingvaldsen (Institute of Marine Research, Norway), Jackie Grebmeier (University of Maryland, USA), Snorre Flo (UNIS, Norway)
Session content:
The central Arctic Ocean is tightly connected to the northern Pacific and Atlantic Oceans through advection processes that link the subarctic regions with the Arctic. In addition to heat and salt, this advection transports nutrients, organic carbon, organisms, pollutants, and metals. All of these objects can be transformed on the continental shelves as they transit into the high Arctic. The Barents and Bering/Chukchi Seas constitute the major inflow shelves. These regions are experiencing large changes such as seawater warming, northward receding Marginal Ice Zones, increased ocean acidification and borealization of the ecosystems, as well as increased human impact from fisheries, petroleum industry, tourism, and vessel traffic. The talks in session D present the latest understanding of the complex Arctic inflow systems.
All Nansen Legacy researchers still actively involved in the project should purchase their travel as they have done previously (follow guidelines at their own institution) and apply for travel reimbursements by their respective partner institutions. The institutions will then send a compiled claim to the project office.
For symposium registration, the project administration will soon send you a booking code by email that will allow you to register for the symposium and book the hotel room through the registration system. Accommodation costs and the participant fee will directly be covered by the Nansen Legacy.