Progress in Oceanography最新文献

{"title":"Mesozooplankton community: Structure, functionality, and food availability in a tropical area of the Southwest Atlantic Ocean","authors":"Cristina de Oliveira Dias ,&nbsp;Adriana Valente Araujo ,&nbsp;Pedro Freitas de Carvalho ,&nbsp;Luis Carlos Pinto de Macedo-Soares ,&nbsp;Daniel Leite Moreira ,&nbsp;Sérgio Luiz Costa Bonecker","doi":"10.1016/j.pocean.2025.103441","DOIUrl":"10.1016/j.pocean.2025.103441","url":null,"abstract":"<div><div>We investigated the taxonomic and functional complexity of a mesozooplankton community and associated trophic relationships in a tropical area of the Southwest Atlantic Ocean. Mesozooplankton communities showed a clear distribution between coastal and oceanic regions. Along the continental shelf, areas influenced by the upwelling of the Cabo Frio and plume of the Paraíba do Sul River, characterized by high productivity and nutrient availability, showed the highest abundance of mesozooplankton. Small-to-medium-sized mesozooplankton species, characterized by current feeding and a broadcast spawning strategy, were dominant over other species. Picoplankton and microplankton were found to be key predictors of the abundance of current-feeding group. For cruise/ambush–feeding group, suspended particulate matter and autotrophic microplankton were significant predictors of their abundance. Ambush-feeding group is primarily influenced by the availability of current-feeding and cruise/ambush–feeding groups and suspended particulate matter. This study provides insights into the functional groups of the zooplankton community in the South Atlantic Ocean and addresses a notable gap in our understanding of interactions at the base of the marine food web across much of the western South Atlantic Ocean. This information is crucial for understanding the potential impacts of global climate change and local disturbances on marine trophic dynamics in the region.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"233 ","pages":"Article 103441"},"PeriodicalIF":3.8,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509084","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 structure, functions, drivers, and dynamics in the Barents Sea and adjacent seas","authors":"R.B. Ingvaldsen ,&nbsp;G. Bratbak ,&nbsp;B. Planque ,&nbsp;J.E. Søreide","doi":"10.1016/j.pocean.2025.103454","DOIUrl":"10.1016/j.pocean.2025.103454","url":null,"abstract":"","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"233 ","pages":"Article 103454"},"PeriodicalIF":3.8,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487127","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}

{"title":"Effect of thermal and non-thermal processes on the variability of ocean surface pCO2 and buffering capacity in the north Indian Ocean","authors":"R. Peter ,&nbsp;J. Kuttippurath ,&nbsp;N. Sunanda ,&nbsp;Kunal Chakraborty","doi":"10.1016/j.pocean.2025.103442","DOIUrl":"10.1016/j.pocean.2025.103442","url":null,"abstract":"<div><div>The oceans have absorbed nearly 30% of the anthropogenic CO₂ that alters the ocean carbon chemistry. The oceanic processes are highly complex, which mandate approaches that couple its physical, chemical and biological states. Here, we use a coupled atmosphere–ocean-biogeochemistry model, incorporating spatially and temporally varying atmospheric CO₂ to simulate the north Indian Ocean (NIO) carbon dynamics for the period 2013–2020. We assess the seasonal variability of Dissolved Inorganic Carbon (DIC), total Alkalinity (ALK), ocean surface <em>p</em>CO₂ and buffering capacity. To assess the mechanisms that control carbon dynamics in the region, we segregate the ocean surface <em>p</em>CO₂ into temperature-driven (thermal) and bio-physical processes induced (non-thermal) <em>p</em>CO₂. We find that the thermally driven <em>p</em>CO₂ is dominant in summer (June, July, August and September; JJAS), but the non-thermal component in winter (December, January and February; DJF) in the northern Arabian Sea (AS). The northern AS is characterised by a deep mixed layer and convection-induced vertical mixing during winter. DIC from the subsurface layer is uplifted to the surface, which results in high ocean surface <em>p</em>CO₂ in winter. Off the Oman coast, the non-thermal processes control the surface <em>p</em>CO₂ in summer. In the northern bay, the thermal component of <em>p</em>CO₂ is dominant in summer and non-thermal component in winter as in northern AS, but their magnitudes are lower due to large riverine flux. The budget analysis reveals strong influence of diffusion, CO₂ flux and biological processes in controlling DIC variability in NIO. Low buffering capacity in upwelling regions indicates that <em>p</em>CO₂ changes are more sensitive to changes in DIC, primarily due to the upwelled DIC-rich surface waters. Therefore, it results in a reduced ability to absorb CO₂. This warrants the need to address recent changes in carbon dynamics in response to the increased levels of atmospheric CO₂.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"233 ","pages":"Article 103442"},"PeriodicalIF":3.8,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487126","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":"Distribution patterns of deep-sea molluscs from the Bering Sea and Aleutian Trench","authors":"Julia D. Sigwart ,&nbsp;Chong Chen ,&nbsp;Gennady M. Kamenev ,&nbsp;Fabrizio Marcondes Machado ,&nbsp;Enrico Schwabe","doi":"10.1016/j.pocean.2025.103440","DOIUrl":"10.1016/j.pocean.2025.103440","url":null,"abstract":"<div><div>The Aleutian Trench, a canyon-like structure in the deep sea floor that parallels the southern fringe of the Aleutian Islands off Alaska, has only been studied by a few previous expeditions. The trench itself and the adjacent island archipelago both present potential dispersal barriers to marine species, which may shape the regional biogeography. We report new findings on the molluscan fauna of the trench and adjacent regions, from the recent “AleutBio” expedition in summer 2022 on the German research vessel <em>Sonne</em>. We recovered over 4300 individual mollusc specimens representing 212 identified taxa in 7 classes (all living taxonomic classes except Polyplacophora), of which 180 could be assigned to a species-level morphospecies. Highlights from our new material include: one monoplacophoran, the dumbo octopus <em>Grimpoteuthis imperator</em> re-collected for the first time since its description, the deepest record for the large-bodied solenogaster family Neomeniidae at 6612 m, the very rare columbariid gastropod <em>Tropidofusus aequilonius</em>, and new hadal records for several bivalves: <em>Rengea murrayi, Limatula</em> cf. <em>vancouverensis, Neilonella abyssopacifica, Neilonella politissima, Catillopecten squamiformis, Parvamussium pacificum,</em> and <em>Setigloma japonica</em> and the bivalve family Sareptidae. Comparing records from the Bering Sea (3490–3655 m), the north rim of the trench (4220–4641 m), the hadal depths of the trench bottom (6181–7287 m), and the southern rim (4790–5330 m), provides a test of potential barriers to the distributions of species across these regions. Of the species found in the Bering Sea, 63 % are also found in the broader Aleutian Trench region. Similarly, of the mollusc species found on the south rim of the trench, 68 % cross the Aleutian Trench and are found on the north rim and/or in the Bering Sea. The dispersal potential of most mollusc species is apparently not restricted by deep-sea trenches or island chains in the North Pacific.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"233 ","pages":"Article 103440"},"PeriodicalIF":3.8,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479314","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}

{"title":"The climatology of the deep particle flux in the oligotrophic western North Atlantic gyre, 1978–2022","authors":"M.H. Conte ,&nbsp;R. Pedrosa-Pàmies ,&nbsp;J.C. Weber ,&nbsp;R.J. Johnson","doi":"10.1016/j.pocean.2025.103433","DOIUrl":"10.1016/j.pocean.2025.103433","url":null,"abstract":"<div><div>The oceanic particle flux controls, in part, ocean biogeochemical cycles and long-term carbon sequestration. The Oceanic Flux Program (OFP), the longest running time series of its kind, has continuously measured the deep particle flux in the oligotrophic Sargasso Sea southeast of Bermuda since 1978. This paper describes the deep flux climatology at the OFP site over the 1978–2022 time period. Mass flux at 500 m, 1500 m and 3200 m depths has averaged 27.2, 34.8 and 36.8 mg m⁻² d^-1, respectively. Carbonates comprise ∼ 60 % of the flux, with lesser amounts of organic matter, opal and lithogenics. Flux magnitude and composition vary seasonally with large interannual variability, particularly in the winter/spring flux maximum. Flux frequency distributions are strongly skewed, especially at 500 m depth where flux magnitude and compositional variability are highest. Flux seasonality, skewness and compositional heterogeneity decrease markedly with depth. A significant component of the deep flux is sourced from large particle production in the deep water column (e.g. suspended material repackaging) rather than directly from the overlying export flux. Lithogenic flux increases five-fold between 500 m and 3200 m depths, underscoring the importance of deep lateral advection and lithogenic particle removal via particle cycling processes. Multidecadal averages in deep carbon fluxes are compared with concurrent monthly data on overlying net primary production (PP) and surface export flux (EF, measured by drifting traps at 150 m depth) at the nearby Bermuda Atlantic Time Series (BATS) site. Carbon fluxes are temporally coherent throughout the water column (within the sample resolution) and lag primary production by ∼ one month. Approximately 0.6 %, 0.5 % and 0.4 % of PP reaches the 500, 1500 and 3200 m depth horizons, respectively, with the highest depth penetration occurring during the Jan-Mar period of peak primary production. Annually, 7.6 % and 6.2 % of the EF reaches the1500 and 3200 m depth horizons, respectively, with the highest transfer efficiency (9.1 % and 7.4 %, respectively at 1500 and 3200 m depths) during the post-bloom (Apr-Jun) period. The OFP flux climatology summarized here provides an important baseline for assessing future consequences of a changing climate on ocean functioning in the oligotrophic North Atlantic gyre.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"234 ","pages":"Article 103433"},"PeriodicalIF":3.8,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611450","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":"Isotopic composition of nitrate in the Western Tropical Pacific Ocean: Biogeochemical signals and their transport","authors":"Wentao Wang ,&nbsp;Zhiming Yu ,&nbsp;Xiuxian Song ,&nbsp;Yongquan Yuan ,&nbsp;Zaixing Wu ,&nbsp;Lianbao Chi","doi":"10.1016/j.pocean.2025.103431","DOIUrl":"10.1016/j.pocean.2025.103431","url":null,"abstract":"<div><div>The Western Tropical Pacific Ocean has a complicated circulation system and plays a significant role in regulating global marine nitrogen cycles and budgets. Powerful insights can be gained by using nitrate isotope (δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^-) techniques. In this study, nitrate concentrations and δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^- values were obtained along meridional (130°E) and zonal (20°N) transects in the Western Tropical Pacific Ocean. The δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^- values ranged from 2.9 to 10.9 ‰ and from 2.0 to 5.7 ‰, respectively. For the water mass in the thermocline originating in the North Pacific, the simultaneously elevated δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^- values indicated nitrate assimilation. The relatively low δ¹⁵N-NO₃^- values in the intermediate water indicated the remineralization of sinking organic matter produced by N₂ fixation at shallow depths, but these signals exhibited a delay in downward propagation in the North Pacific subtropical gyre. For water masses originating in the Southern Hemisphere, the variations in nitrate isotopes might be attributed mainly to physical mixing, including diapycnal mixing between the thermocline and intermediate water and lateral advection from the Equatorial Undercurrent. Furthermore, according to end-member mixing calculations, at least 62 % of the nitrate in the water of the North Subsurface Countercurrent was derived from the Southern Hemisphere, whereas North Pacific Tropical Water, South Pacific Tropical Water and nutrient-rich upwelling accounted for 50 %, 12 % and 38 %, respectively, of the nitrate in the water of the North Equatorial Countercurrent.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"233 ","pages":"Article 103431"},"PeriodicalIF":3.8,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474806","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":"Temporal variability of bottom hypoxia in open and semi-enclosed coastal areas in an upwelling region","authors":"Richard Muñoz ,&nbsp;Fabián J. Tapia ,&nbsp;Marcus Sobarzo","doi":"10.1016/j.pocean.2025.103435","DOIUrl":"10.1016/j.pocean.2025.103435","url":null,"abstract":"<div><div>Hypoxia events driven by the onshore advection of oxygen-poor upwelling waters have become increasingly common along Eastern Boundary Upwelling Systems (EBUS). More frequent or intense drops in nearshore oxygen concentrations can impact the behavior, population dynamics, and geographic distribution of many coastal species. To better understand these effects, it is necessary to determine the periodicity of hypoxia in the inner shelf, its response to upwelling-favorable winds, and the local factors that may modify its intensity and duration. Here, we used a two-year record (March 2017–February 2019) of near-bottom dissolved oxygen (DO) and water temperature from seven sites spanning 260 km of the upwelling coast of Central Chile to characterize the local variability in oxygen concentration and its association with coastal winds. The temporal patterns observed in the inner shelf were compared with 13.5 years of monthly hydrographic profiles (2002–2015) from a mid-shelf station located ca. 30 km offshore. The spatial structure of nearshore hypoxia was inferred from hydrographic data gathered during two surveys conducted in winter 2018 and late summer 2019. Inner-shelf hypoxia (DO<span><math><mo>&lt;</mo></math></span>2.0 mg/L) occurred predominantly in the austral summer and exhibited substantial among-site differences in its persistence and timing relative to wind-driven upwelling. The mean duration of summertime hypoxia events ranged between 1 and 9 days, except for a site at the innermost section of the Gulf of Arauco, where events could be as long as 62 days. Hypoxic waters appeared at the inner shelf after 1–2 days of sustained upwelling-favorable winds (59% of the hypoxia events occurred after <span><math><mo>≤</mo></math></span> 2 days of persistent wind). The seasonality and vertical structure of hypoxia were apparent in the mid-shelf monthly time series, with the hypoxic layer’s upper limit ascending to 20–30 m depths during spring-summer (October–March) and receding to 45–60 m in autumn-winter (May–September). Hydrographic properties of the hypoxic layer pointed to Equatorial Subsurface Water (ESSW) as the source water mass for mid-shelf hypoxia throughout the year. These properties were consistent with those observed on the inner shelf. Among the seven inner-shelf sites, Arauco showed the most persistent (70% of the time spanned by our records) and severe hypoxia, with DO levels below those observed at the mid-shelf during active upwelling. We hypothesize that these conditions respond to a combination of physical phenomena and coastal eutrophication that locally enhance thermal stratification, productivity, and benthic oxygen consumption, thus amplifying the severity of hypoxia and physiological stress for marine organisms inside the Gulf of Arauco.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"233 ","pages":"Article 103435"},"PeriodicalIF":3.8,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436440","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":"Strengthened double-diffusive convection induced by the combined effect of tropical cyclones and a mesoscale eddy","authors":"Yanwei Zhang ,&nbsp;Weihan Ruan ,&nbsp;Danni Lyu ,&nbsp;Jiancheng Yu","doi":"10.1016/j.pocean.2025.103438","DOIUrl":"10.1016/j.pocean.2025.103438","url":null,"abstract":"<div><div>Double-diffusive convection (DDC) is a critical driving mechanism for diapycnal mixing in the ocean. However, there is limited quantitative investigation on the impacts of dynamic ocean-atmospheric processes, such as the interaction between tropical cyclones and mesoscale eddies, on DDC generation. In this study, we analyzed the cyclone-eddy induced DDC based on measurements obtained by an underwater glider in the northern South China Sea, where is frequently impacted by tropical cyclones and eddies. We observed abnormally increased salinity and a notable upwelling resulting from cyclone-eddy interaction. Our observations further reveal the coexistence of detached salt fingers (SF) and shear-driven turbulence. Strengthened salt finger dominates DDC with SF-driven salinity diapycnal diffusivity (10⁻⁴ m² s⁻¹) in the deepened halocline, which is an order of magnitude higher than background values. Shear-driven turbulence, characterized by large density overturns below 600 m, is generated due to enhanced geostrophic shear around the eddy. Further investigation indicates that SF thermohaline staircases evolve from lateral saline fronts driven by Ekman-pumping-induced upwelling and Kuroshio intrusion. The convective structure generates strong diapycnal mixing and vertical/lateral salinity fluxes that are urgently needed to be incorporated into estimations of ocean energy/material balance and ocean modeling.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"232 ","pages":"Article 103438"},"PeriodicalIF":3.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422009","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}

{"title":"Nutricline heaving regulates carbon export in the South China Sea","authors":"Chuanjun Du ,&nbsp;Minhan Dai ,&nbsp;Ying He ,&nbsp;Kuanbo Zhou ,&nbsp;Shuh-Ji Kao","doi":"10.1016/j.pocean.2025.103437","DOIUrl":"10.1016/j.pocean.2025.103437","url":null,"abstract":"<div><div>The export of phytoplankton-synthesized particulate organic carbon (POC) from the upper ocean to the depth removes CO₂ from the atmosphere, playing a critical role in the global climate system. However, substantial data and knowledge gaps in the spatial and temporal variability of the POC export hamper a full spectrum of understanding to the controls of POC export at both seasonal and basin scales. Here, we developed an optimized one-dimensional biogeochemical model, which well simulates the seasonal variations of biogeochemical parameters at the South-East Asia Time-series Study station in the South China Sea (SCS). Applying this model, we further examined the climatology of POC fluxes in the SCS using a high-quality nutrient dataset derived from an algorithm based on a relationship between field observed nutrients and temperature/salinity with high spatiotemporal coverage. The POC fluxes at 100 m deep range from 0.24 to 12.7 mmol C m⁻² d⁻¹ and exhibit evident spatial and seasonal variations. During the summer (from June to August), the POC fluxes in the northern and northwestern SCS regions are higher compared to the central and southern SCS regions. In winter (from December to February), the POC fluxes in the northern SCS are significantly enhanced. Overall, the northern and western basins exhibit higher POC fluxes compared to the central and southeastern basins in all four seasons. Seasonally, the basin averaged POC fluxes in spring and winter exhibit higher values than that in summer and fall. At the relatively eutrophic regions where surface nitrate (NO₃⁻) concentrations &gt; 0.1 μmol L⁻¹, the surface NO₃⁻ concentrations are the primary factor influencing the distribution of POC fluxes, particularly in winter and in the northern SCS. In contrast, within the vast oligotrophic environment, the subsurface nutricline heaving driven by upwelling/downwelling induced by horizontal convergences/divergences at both meso- and basin scales, plays a pivotal role in determining the distribution of POC fluxes. Our findings underscore the significance of subsurface nutricline heaving in driving carbon export in the oligotrophic ocean.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"232 ","pages":"Article 103437"},"PeriodicalIF":3.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429963","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 Labrador Current cold front shaping the Atlantic salmon homing migration routes from the waters off Southern Greenland to eastern North America","authors":"Christiane Dufresne ,&nbsp;Diane Lavoie ,&nbsp;Martha Robertson ,&nbsp;Julien April ,&nbsp;Chantelle Burke ,&nbsp;Jon Carr ,&nbsp;Joël Chassé ,&nbsp;Frédéric Cyr ,&nbsp;Jason Daniels ,&nbsp;Levi Denny ,&nbsp;Shelley Denny ,&nbsp;Guoqi Han ,&nbsp;Ian Jonsen ,&nbsp;Timothy F. Sheehan ,&nbsp;John Fredrik Strøm ,&nbsp;Marc Trudel ,&nbsp;Frederick Whoriskey","doi":"10.1016/j.pocean.2025.103439","DOIUrl":"10.1016/j.pocean.2025.103439","url":null,"abstract":"<div><div>Atlantic salmon (<em>Salmo salar</em>) experienced drastic population declines from the mid-1970 s to the early 1990′s throughout their range. The survival of the salmon while at sea is considered as the main driver of these declines, even though the underlying mechanisms are poorly understood. This study aims at improving the general understanding of the ocean distribution and migration timing of sub-adult salmon returning to North America from the waters off southern Greenland that could help determine the drivers of marine mortality. We used animal biotelemetry and numerical modeling to improve our knowledge of Atlantic salmon migratory behavior. We used data from 43 North American Atlantic salmon tagged at West Greenland, of which 5 individuals migrated towards their native rivers, and developed an individual-based model to simulate homing migration from their feeding grounds in South Greenland towards the coastal areas of their native rivers. The tagged and simulated salmon exhibited similar behavior when they encountered the cold water front formed by the southward flowing Labrador Current. The salmon either crossed the Labrador Current near the Newfoundland shelf break or continued their route southward along the warmer side of the cold front. These two pathways emerged as the migration routes split where the shelf slope is less steep. This discontinuity along the shelf break leads to a highly dynamic region, a high sea surface temperature variability, and occasional breaches in the thermal front that favor on-shelf fish migration. The salmon trajectories appear to be deflected when the front temperature is 1 °C or less. The 1 °C isotherm would thus bound the thermal distribution of North American Atlantic salmon and shape the species migration routes.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"233 ","pages":"Article 103439"},"PeriodicalIF":3.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436441","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}