Progress in Oceanography最新文献

{"title":"Machine learning algorithm reveals surface deoxygenation in the Agulhas Current due to warming","authors":"T.B. Mashifane, L. Braby, M. Pikiso, S. Sunnassee–Taukoor, R.S. Rapolaki, M.N. Ragoasha","doi":"10.1016/j.pocean.2024.103407","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103407","url":null,"abstract":"The Agulhas Current is the strongest western boundary current (WBC) in the Southern Hemisphere with a significant impact on the global climate. Through the Agulhas leakage, it transports warm, saline waters into the South Atlantic Ocean. In recent years, a warming trend has been highlighted in the Agulhas Current, with possible implications for dissolved oxygen ([O<ce:inf loc=\"post\">2</ce:inf>]) due to the link between warming and reduced solubility – dynamics that remain relatively unknown in the region. To address this knowledge gap, we use the random forest regression algorithm to predict near–surface [O<ce:inf loc=\"post\">2</ce:inf>] from multiple predictors in the Agulhas Current, presenting the first analysis of these dynamics. The Agulhas–RFR algorithm predicts [O<ce:inf loc=\"post\">2</ce:inf>] exceptionally well, with permutation importance from the ensemble indicating that sea surface temperature (SST) is the highest–ranking predictor. Seasonal changes in solubility, wind, and productivity drive [O<ce:inf loc=\"post\">2</ce:inf>] and the [O<ce:inf loc=\"post\">2</ce:inf>] flux in the Agulhas Current. The seasonal [O<ce:inf loc=\"post\">2</ce:inf>] flux to the atmosphere reaches –1.84 mol m<ce:sup loc=\"post\">−2</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup> during the austral winter across the Agulhas Current. A significant decreasing [O<ce:inf loc=\"post\">2</ce:inf>] trend of up to –7 µmol kg<ce:sup loc=\"post\">−1</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup>, attributed to warming, is revealed for the period from 2000 to 2023. Strengthening westerlies and cooling contribute to [O<ce:inf loc=\"post\">2</ce:inf>] drawdown towards the Indian Ocean gyre. The Agulhas–RFR algorithm reveals a declining [O<ce:inf loc=\"post\">2</ce:inf>] trend of –2.29 ± 0.61 µmol kg<ce:sup loc=\"post\">−1</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup> across the Agulhas Current for the study period, representing a 1.4% deoxygenation rate, which is slightly higher than global estimates.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"21 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Parameterization of Langmuir circulation under geostrophic effects using the data-driven approach","authors":"Yu Gao, Jinbao Song, Shuang Li, Chengcheng Yu, Peng Hao","doi":"10.1016/j.pocean.2024.103403","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103403","url":null,"abstract":"Langmuir circulation (LC) and geostrophic effects are crucial physical processes that affect upper-ocean mixing. This study investigates the impact of LC on ocean mixing with a particular focus on geostrophic effects. By combining feedforward neural network (FNN) and Large Eddy Simulation (LES), this study simulated the interaction between varying intensities of LC and different geostrophic effects. The results revealed that the eddy viscosity coefficient in high-latitude areas exceeded that in mid-latitude areas, with this difference being most pronounced in the surface layer and gradually diminishing with depth. Analysis of the vertical momentum flux, upper mixed layer depth, and horizontal velocity shear characteristics demonstrates that geostrophic effects influence high-latitude ocean turbulence and mixing processes. Based on these findings, an improved LC parameterization scheme (KPPLT-FNN) incorporating geostrophic effects was developed, which relies on friction velocity, geostrophic effect, turbulent Langmuir number, and seawater depth. In GOTM, comparative analysis with observational data from COREII and the Ocean Climate Station Papa indicates that KPPLT-FNN demonstrates superior performance in simulating summer ocean temperature, ocean salinity, and winter mixed layer depth. Statistical analysis confirms that the simulation results incorporating geostrophic effects outperform those without such considerations. This study provides valuable insights into improving the accuracy of ocean model simulations.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"119 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A shifting chessboard: Projections of prawn, capelin, mesopelagic fish, zooplankton, and their Nordic and Barents Seas food web under climate change","authors":"Ina Nilsen, Cecilie Hansen, Isaac C. Kaplan","doi":"10.1016/j.pocean.2024.103387","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103387","url":null,"abstract":"As climate change is already altering ocean temperatures, there is an urgent need to understand how environmental changes will affect marine ecosystems. Although great efforts have been made to understand the impacts of ocean warming, there are still uncertainties regarding effects on lower trophic levels and how these may propagate to higher trophic levels. In this study, physics from three different climate projections (SPP1-2.6, SSP2-4.5 and SSP5-8.5) were applied to study the impact of rising temperatures in the Nordic and Barents Seas Atlantis ecosystem model (NoBa Atlantis). We also included variation in phyto- and zooplankton levels to account for the uncertainty regarding how lower trophic levels might respond to climate change. This approach by us is the first study where three different sets of physics have been applied to an end-to-end ecosystem model representing the Nordic and Barents Seas. We therefore treat the projected results with caution, and focus on the underlying mechanisms that drive the changes, to inform future ecosystem studies. The spatial nature of the model (a “shifting chessboard”) allowed us to study how local changes in temperature and prey could affect entire populations. For instance, the thermal niches of mesopelagic fish allowed for an increase in abundance in northern areas, benefiting predators such as blue whiting. On the other hand, thermal limits of capelin together with zooplankton overlap resulted in declines, which subsequently led to reduction in cod growth. This study demonstrates how ecosystem studies could benefit from both modeling and empirical studies that consider not only broad-brush impacts on primary production and trophic transfer, but also spatial considerations of local predator–prey interactions, thermal habitat and spawning-area suitability.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"21 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Community structure of fish larvae associated with advections of the Kuroshio and its neighboring waters","authors":"Toru Kobari, Yusuke Manako, Airi Hara, Kaori Yamanoue, Takafumi Azuma, Ryuji Fukuda, Yi-Chen Wang, Masafumi Kodama, Gen Kume","doi":"10.1016/j.pocean.2024.103386","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103386","url":null,"abstract":"The Kuroshio has been long thought to be disadvantageous as nursery grounds for larval fishes due to the low plankton standing stocks under the oligotrophic conditions. Despite of the potential risk for survival and growth, early life stages of various fishes appear abundantly in the Kuroshio and its neighboring waters. Here, we report what kind of taxonomic groups establish community structure of larval fishes in the Continental shelf waters (CW) and the Kuroshio (KW). 16 orders and 78 families were classified in the present study. Mesopelagic fishes more abundantly appeared in the KW than in the CW, while larval fish abundance was not different between the two areas. Multivariate analysis demonstrated the regional difference of the taxonomic compositions, represented by Callionymidae, Bothidae, Labridae and Bregmacerotidae for the CW and Gonostomatidae, Myctophidae and Notosudidae for the KW. Abundance of fish larvae to ambient salinity exhibited significantly positive correlations for Gonostomatidae, <ce:italic>Sigmops gracilis</ce:italic> and <ce:italic>Myctophum orientale</ce:italic> predominated in the KW and negative correlations for Labridae appeared abundantly in the CW. These results suggest that mixture of advected specimens from the coastal and Kuroshio waters also contribute to larval fish community with high biodiversity and comparable abundance between the Kuroshio and its neighboring waters.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"178 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abundance and estimated food consumption of seabirds in the pelagic ecosystem in the eastern Indian sector of the Southern Ocean","authors":"Nobuo Kokubun, Kohei Hamabe, Nodoka Yamada, Hiroko Sasaki, Bungo Nishizawa, Yutaka Watanuki, Hiroto Murase","doi":"10.1016/j.pocean.2024.103385","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103385","url":null,"abstract":"Quantification of abundance and food consumption of seabirds are key to understand characteristics and ecological functions of local marine ecosystem due to their abundance and diversity in foraging areas, habitat, behavior, mobility and prey types. This study aimed to quantify seabird abundance in pelagic areas in the eastern Indian sector of the Southern Ocean (80–150E°) based on an at-sea observational study conducted during the 2018/19 austral summer season. We estimated food consumption by seabirds based on their biomass, estimated field metabolic rates, number of days spent in the areas, and diet composition. Among the five functional seabird groups (penguins, albatrosses/giant petrels, shearwaters, petrels/Charadriiformes, prions/storm-petrels), shearwaters, non-Antarctic resident, were the most dominant taxa both by abundance (15,650,000 birds) and biomass (9,332 tonnes) in the study area during the summer. Most of the prey consumed by all seabirds in the area was presumed to be Antarctic krill (55,504 tonnes) and pelagic fishes (91,695 tonnes), such as myctophids. Although the total food consumption by the seabirds during the summer (209,973 tonnes) was lower than that reported in the Antarctic neritic areas (e.g., 753,000 tonnes in the neighboring Prydz Bay region), the higher proportion of non-resident shearwaters in biomass and estimated food consumption (85%) were the characteristic of the study area. Our results highlight the characteristics of the ecological importance of the study area in which seabirds consume Antarctic krill and pelagic fishes in the upper layer of the water column, and its nutrients are easily transported by the seabirds as their subcutaneous fat or stomach oil to the outside of the areas.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"113 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Food web analysis shows an exacerbated dependence of zooplankton on detritus in oligotrophic systems due to ocean warming","authors":"Luca Russo, Matteo Loschi, Daniele Bellardini, Roberta Congestri, Michael W. Lomas, Simone Libralato, Domenico D’Alelio","doi":"10.1016/j.pocean.2024.103389","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103389","url":null,"abstract":"Ocean warming can affect plankton both directly, through altered metabolic activities, and indirectly, modifying the physical–chemical properties of the water column, with possible effects on ecosystem functioning. To evaluate the combined action of warming-related physiological responses and environmental changes on plankton assemblage functioning, we carried out a long-term analysis (from 1994 to 2019) of the Bermuda Atlantic Time-series Study (BATS) dataset where ocean warming and stratification have driven a decrease in net primary production over the last decade. Using the time series of plankton observations, we assembled 1000 replicates of a food web model for each year. We observed that the total flow of matter through the model remained constant over time, despite the increased oligotrophication, due to global warming, after 2014. In fact, the plankton food web remained robust through re-modulated trophic interactions with an increased detritivory to herbivory ratio of the food web over time. Moreover, there was difficulty to re-establish broken trophic connections of the food web (increased relative internal ascendency) due to global warming. Thanks to trophic plasticity, the reduced zooplankton dependence on herbivory was compensated by significant increase in the dependence on carnivory and detritivory, highlighting the crucial role of trophic interactions in buffering significant environmental short-term changes.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"82 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of applying skin temperature corrections to gas exchange models on air-sea oxygen flux estimates","authors":"Bo Yang ,&nbsp;Chris Langdon","doi":"10.1016/j.pocean.2024.103383","DOIUrl":"10.1016/j.pocean.2024.103383","url":null,"abstract":"<div><div>The skin of the ocean is often slightly cooler than the surface mixed layer due to net surface heat loss (cool skin effect), and sometimes slightly warmer in areas with extreme solar radiation (warm layer effect). In previous work (<span><span>Yang et al., 2022</span></span>), with the skin temperature correction term (ΔT) derived from the fifth generation European Center for Medium-Range Weather Forecasts Reanalysis (ERA5) and oxygen (O₂) data from three Argo profiling floats, we showed that skin temperature correction is critical for air-sea O₂ flux calculation. In this work, we applied the same method to the World Ocean Atlas 2018 (WOA2018) dataset with two widely used air-sea gas exchange models (an empirically derived quadratic bulk flux model W14, and a mechanistic bubble-mediated model E19), to evaluate the influence of skin temperature correction on large-scale air-sea O₂ flux estimate. To avoid the influence of sea ice on air-sea gas exchange (and possibly on the ERA5 reanalysis), we limited our analysis between 50°S and 50°N. The result revealed that for both W14 and E19 models the skin temperature correction lowered annual sea-to-air O₂ flux between 50°S and 50°N by 25 % for the E19 model and by 22 % for the W14 model. Larger ΔT (further from zero), higher temperature, higher wind speed, and larger O₂ concentration difference across the air-sea interface led to larger difference in O₂ fluxes calculated with and without the skin temperature correction. With the E19 model, using the ERA5-based ΔT for areas between 50°S and 50°N and a fixed ΔT of −0.17 K for high latitude areas (50°N-90°N and 50°S-90°S), we made an estimate of O₂-based global air-to-sea carbon flux of 3.84 Pg C yr⁻¹ (using O₂ to C ratio of 1.45 from <span><span>Hedges et al., 2002</span></span>), which was comparable to other latest estimates.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"230 ","pages":"Article 103383"},"PeriodicalIF":3.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142694103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perspectives on Northern Gulf of Alaska salinity field structure, freshwater pathways, and controlling mechanisms","authors":"Isaac Reister,&nbsp;Seth Danielson,&nbsp;Ana Aguilar-Islas","doi":"10.1016/j.pocean.2024.103373","DOIUrl":"10.1016/j.pocean.2024.103373","url":null,"abstract":"<div><div>The biologically productive Northern Gulf of Alaska (NGA) continental shelf receives large inputs of freshwater from surrounding glaciated and non-glaciated watersheds, and a better characterization of the regional salinity spatiotemporal variability is important for understanding its fate and ecological roles. We here assess synoptic to seasonal distributions of freshwater pathways of the Copper River discharge plume and the greater NGA continental shelf and slope using observations from ship-based and towed undulating conductivity-temperature-depth (CTD) instruments, satellite imagery, and satellite-tracked drifters. On the NGA continental shelf and slope we find low salinities not only nearshore but also 100–150 km from the coast (i.e. average 0–50 m salinities less than 31.9, 31.3, and 30.8 in spring, summer, and fall respectively) indicating recurring mid-shelf and shelf-break freshwater pathways. Close to the Copper River, the shelf bathymetry decouples the spreading river plume from the direct effects of seafloor-induced steering and mixing, allowing iron- and silicic acid-rich river outflow to propagate offshore within a surface-trapped plume. Self-organized mapping analysis applied to true color satellite imagery reveals common patterns of the turbid river plume. We show that the Copper River plume is sensitive to local wind forcing and exerts control over water column stratification up to ∼100 km from the river mouth. Upwelling-favorable wind stress modifies plume entrainment and density anomalies and plume width. Baroclinic transport of surface waters west of the river mouth closely follow the influence of alongshore wind stress, while baroclinic transport east of the river mouth is additionally modified by a recurring or persistent gyre. Our results provide context for considering the oceanic fate of terrestrial discharges in the Gulf of Alaska.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103373"},"PeriodicalIF":3.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142643110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytic solutions for equatorial, Kelvin, Rossby, and Yanai beams","authors":"Julian P. McCreary Jr. ,&nbsp;Theodore W. Burkhardt","doi":"10.1016/j.pocean.2024.103378","DOIUrl":"10.1016/j.pocean.2024.103378","url":null,"abstract":"<div><div>Wind-driven equatorial Kelvin, Rossby, and Yanai waves are known to propagate vertically, as well as zonally, and packets of them can form “beams” that descend into the deep ocean along ray paths consistent with wave-group theory. Here, we obtain analytic solutions to a simplified ocean model that provide a more complete description of beam properties and dynamics than in previous studies.</div><div>The model is a linear, continuously stratified (LCS) system, in which the bottom is ignored and the background Vaisala frequency <span><math><msub><mrow><mi>N</mi></mrow><mrow><mi>b</mi></mrow></msub></math></span> is constant. Solutions are forced by an oscillatory wind stress, <span><math><mrow><msup><mrow><mi>τ</mi></mrow><mrow><mi>α</mi></mrow></msup><mo>=</mo><msubsup><mrow><mi>τ</mi></mrow><mrow><mi>o</mi></mrow><mrow><mi>α</mi></mrow></msubsup><mi>X</mi><mfenced><mrow><mi>x</mi></mrow></mfenced><mo>exp</mo><mfenced><mrow><mo>−</mo><mi>i</mi><mi>σ</mi><mi>t</mi></mrow></mfenced></mrow></math></span>, where: <span><math><mi>α</mi></math></span> is <span><math><mi>x</mi></math></span> or <span><math><mi>y</mi></math></span>; <span><math><mrow><mi>X</mi><mfenced><mrow><mi>x</mi></mrow></mfenced></mrow></math></span> is confined to the region <span><math><mrow><mo>−</mo><mi>L</mi><mo>&lt;</mo><mi>x</mi><mo>&lt;</mo><mi>L</mi></mrow></math></span> and increases and decreases monotonically; and <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mi>α</mi></mrow></msup></math></span> enters the ocean as a body force with the profile <span><math><mrow><mi>Z</mi><mfenced><mrow><mi>z</mi></mrow></mfenced><mo>=</mo><mfenced><mrow><mn>2</mn><mo>/</mo><mi>π</mi></mrow></mfenced><mi>h</mi><mo>/</mo><mfenced><mrow><msup><mrow><mi>z</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>+</mo><msup><mrow><mi>h</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfenced></mrow></math></span>. Under these restrictions, solutions can be represented as cosine transforms in <span><math><mi>z</mi></math></span> that can be readily inverted.</div><div>Beam solutions for all three wave types have similar mathematical forms, and hence share many properties. Among other things, the solutions show how the structure and amplitude of beams depend on the above model parameters. Potential impacts of processes neglected in the solutions are noted.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"230 ","pages":"Article 103378"},"PeriodicalIF":3.8,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in prey-predator interactions in an Arctic food web under climate change","authors":"Nicolas Dupont ,&nbsp;Joël M. Durant ,&nbsp;Øystein Langangen ,&nbsp;Leif Christian Stige","doi":"10.1016/j.pocean.2024.103380","DOIUrl":"10.1016/j.pocean.2024.103380","url":null,"abstract":"<div><div>Global warming affects marine ecosystems by changing environmental conditions, ecosystem structure, and ecosystem functioning. In parts of the Arctic, increased sea temperature and decreased sea ice have led to a poleward expansion of boreal species and increased their interactions with native Arctic species. To investigate and quantify the changing interactions in an Arctic marine food web under new environmental conditions, we studied the interactions between key prey fish species in the seasonally ice-covered parts of the Barents Sea: adult polar cod (<em>Boreogadus saida</em>) and capelin (<em>Mallotus villosus</em>) and one of the major predators in the system: Atlantic cod (<em>Gadus morhua</em>). For this, we compared the predictive performance of threshold models predicting the abundance of adult polar cod as a function of Atlantic cod. Each model was associated with a hypothesis describing prey-predator interactions in different environmental conditions defined by threshold values of summer sea-ice or capelin stock biomass. The best predictive model showed that the predation effect of Atlantic cod on polar cod was strongest in years of low summer sea ice cover and low capelin stock biomass. Our results exemplified that Arctic species such as polar cod may experience increased predation pressure under climate change from boreal species such as Atlantic cod. These effects depend, however, not only on changes in abiotic drivers of species distributions, but also on food-web interactions involving mid-trophic level species such as capelin.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"229 ","pages":"Article 103380"},"PeriodicalIF":3.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}