Pub Date : 2026-01-01DOI: 10.1016/j.pocean.2025.103658
Sang Lyeol Kim , Hyung-Gon Lee , Kyung-Hee Oh , Kongtae Ra , Ok Hwan Yu
The Kuroshio Current, a major western boundary current in the North Pacific, intrudes into the southern seas of Korea through the Tsushima Warm Current (TWC) and exerts strong influence on benthic ecosystems. From 2015 to 2024, we assessed seasonal variability in hydrography, sediments, and benthic macrofauna. Summer conditions featured warmer surface waters (27.8 °C), lower dissolved oxygen, and more organic-rich, coarse sediments. Benthic communities showed clear seasonality, with all community metrics highest in spring, lowest in winter, and intermediate in summer and autumn. Sediments were mainly sandy silt and silty sand, dominated by polychaetes, with higher species density and biomass observed in summer and autumn. Bottom temperature was modestly related to richness and density, while biomass declined with surface warming. These patterns closely resemble observations from other Kuroshio-affected regions, including seasonal oxygen depletion and organic enrichment on the East China Sea shelf, enhanced nutrient flux and benthic shifts off Taiwan, and polychaete-dominated assemblages in southern Japan. The convergence of these features across Kuroshio-influenced margins provides evidence that the benthic ecosystems of Korea are directly shaped by the hydrographic and biogeochemical forcing of the Kuroshio system.
{"title":"Influence of the Kuroshio Current on the benthic communities in the southern seas of Korea","authors":"Sang Lyeol Kim , Hyung-Gon Lee , Kyung-Hee Oh , Kongtae Ra , Ok Hwan Yu","doi":"10.1016/j.pocean.2025.103658","DOIUrl":"10.1016/j.pocean.2025.103658","url":null,"abstract":"<div><div>The Kuroshio Current, a major western boundary current in the North Pacific, intrudes into the southern seas of Korea through the Tsushima Warm Current (TWC) and exerts strong influence on benthic ecosystems. From 2015 to 2024, we assessed seasonal variability in hydrography, sediments, and benthic macrofauna. Summer conditions featured warmer surface waters (27.8 °C), lower dissolved oxygen, and more organic-rich, coarse sediments. Benthic communities showed clear seasonality, with all community metrics highest in spring, lowest in winter, and intermediate in summer and autumn. Sediments were mainly sandy silt and silty sand, dominated by polychaetes, with higher species density and biomass observed in summer and autumn. Bottom temperature was modestly related to richness and density, while biomass declined with surface warming. These patterns closely resemble observations from other Kuroshio-affected regions, including seasonal oxygen depletion and organic enrichment on the East China Sea shelf, enhanced nutrient flux and benthic shifts off Taiwan, and polychaete-dominated assemblages in southern Japan. The convergence of these features across Kuroshio-influenced margins provides evidence that the benthic ecosystems of Korea are directly shaped by the hydrographic and biogeochemical forcing of the Kuroshio system.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103658"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786142","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}
Pub Date : 2026-01-01DOI: 10.1016/j.pocean.2025.103656
Kharis R. Schrage , Johanna N.J. Weston , Alexandra Kraberg , Rebecca McPherson , Wilken-Jon Von Appen , Loreley Lago , Kirstin S. Meyer-Kaiser
Rapid Arctic warming is altering marine ecosystems, yet the diversity and dispersal of meroplankton—larval stages of benthic invertebrates—remain poorly understood in the region. This study presents the first detailed characterization of meroplanktonic communities in the Fram Strait, based on summer collections made in 2023 and 2024 across the Long-Term Ecological Research observatory HAUSGARTEN. Using integrated and depth-stratified vertical net tows and DNA barcoding, we identified 77 taxa, 33 of which were identified to the species level. Meroplankton were most dense in the upper 200 m, dominated by bivalves and ophiuroids, with significant patchiness across depths and regions. Community composition was related to water mass and phytoplankton community composition (explaining 25 % of the variability among stations), but not to sea ice cover, reflecting a complex coupling between benthic reproduction and pelagic conditions. Lagrangian particle tracking revealed that larvae in the West Spitsbergen Current may originate from as far south as northern Norway, while East Greenland Current larvae likely derive from central Arctic waters. Species-level investigations of meroplankton distribution are critical for assessing existing biodiversity and detecting changes to species composition. Here, most larvae belonged to local or Arcto-Boreal species, though seven taxa had no adult records in the Fram Strait, which may indicate larvae being wasted (not surviving to settlement), broad connectivity among coastal Arctic populations, and/or range expansions. These findings highlight the interplay between hydrography and hydrodynamics, larval ecology, and climate-driven change, and establish a baseline for monitoring Arctic benthic connectivity and biodiversity under ongoing ocean warming.
{"title":"Diversity, drivers, and dispersal of high Arctic meroplanktonic communities","authors":"Kharis R. Schrage , Johanna N.J. Weston , Alexandra Kraberg , Rebecca McPherson , Wilken-Jon Von Appen , Loreley Lago , Kirstin S. Meyer-Kaiser","doi":"10.1016/j.pocean.2025.103656","DOIUrl":"10.1016/j.pocean.2025.103656","url":null,"abstract":"<div><div>Rapid Arctic warming is altering marine ecosystems, yet the diversity and dispersal of meroplankton—larval stages of benthic invertebrates—remain poorly understood in the region. This study presents the first detailed characterization of meroplanktonic communities in the Fram Strait, based on summer collections made in 2023 and 2024 across the Long-Term Ecological Research observatory HAUSGARTEN. Using integrated and depth-stratified vertical net tows and DNA barcoding, we identified 77 taxa, 33 of which were identified to the species level. Meroplankton were most dense in the upper 200 m, dominated by bivalves and ophiuroids, with significant patchiness across depths and regions. Community composition was related to water mass and phytoplankton community composition (explaining 25 % of the variability among stations), but not to sea ice cover, reflecting a complex coupling between benthic reproduction and pelagic conditions. Lagrangian particle tracking revealed that larvae in the West Spitsbergen Current may originate from as far south as northern Norway, while East Greenland Current larvae likely derive from central Arctic waters. Species-level investigations of meroplankton distribution are critical for assessing existing biodiversity and detecting changes to species composition. Here, most larvae belonged to local or Arcto-Boreal species, though seven taxa had no adult records in the Fram Strait, which may indicate larvae being wasted (not surviving to settlement), broad connectivity among coastal Arctic populations, and/or range expansions. These findings highlight the interplay between hydrography and hydrodynamics, larval ecology, and climate-driven change, and establish a baseline for monitoring Arctic benthic connectivity and biodiversity under ongoing ocean warming.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103656"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145844680","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}
Pub Date : 2025-12-30DOI: 10.1016/j.pocean.2025.103662
Ali Johnson Exley , Amy Bower , Xiaobiao Xu , Sijia Zou , Anna Pinckney , Heather Furey
Iceland–Scotland Overflow Water (ISOW), a dense water mass formed in the Nordic Seas, spills into the Iceland Basin through the Iceland-Faroe Ridge and Faroe Shetland Channel before propagating southwestward along the eastern flank of the Reykjanes Ridge as a deep boundary current, contributing to the lower limb of the Atlantic Meridional Overturning Circulation. Recent work has demonstrated that pathways of ISOW out of the Iceland Basin are complex and variability has not been explored on interannual and longer timescales. In this study, we use the basin-scale, eddy-rich (1/12°), 40-year Atlantic Hybrid Coordinate Ocean Model (HYCOM) simulation to investigate the variability in ISOW export pathways. Simulated Lagrangian particles are released within the ISOW layer ( 27.80 kg m−3) at two locations along the eastern flank of the Reykjanes Ridge and classified according to their export pathway: over the Reykjanes Ridge, through the Charlie Gibbs Fracture Zone (CGFZ) or into the Western European Basin (WEB). We show that export over the Reykjanes Ridge exhibits variability on timescales from 2.5 years to decadal and is strongly correlated with mid-depth northward transport into the Iceland Basin forced by fluctuations in the North Atlantic Current (NAC), suggesting a link to large-scale gyre dynamics. Export through the CGFZ is characterized by variability of 2.5–5 years and is influenced by the meridional position of the eastward-flowing NAC within the CGFZ, which can block ISOW export and divert particles into the WEB. Export pathways are shown to exhibit a significant depth-dependence such that shallower layers are more strongly impacted by the surface circulation while deeper layers are more subject to topographic steering, results that are corroborated by utilizing observations from RAFOS floats deployed during the OSNAP campaign. Together, these findings illustrate the high-degree of variability in pathways of ISOW export and contributes to the growing body of evidence that challenges the notion of a single, dominant pathway out of the Iceland Basin.
冰岛-苏格兰溢水（ISOW）是北欧海域形成的密集水团，在沿雷克雅内斯海脊东侧向西南方向传播之前，通过冰岛-法罗海脊和法罗设得兰海峡流入冰岛盆地，形成了大西洋经向翻转环流的下端。最近的研究表明，冰岛盆地外的ISOW路径是复杂的，年际和更长的时间尺度上的变化尚未得到探索。在这项研究中，我们使用盆地尺度、富涡（1/12°）、40年大西洋混合坐标海洋模式（HYCOM）模拟来研究ISOW输出路径的变化。模拟拉格朗日粒子在雷克雅内斯脊东侧两个位置的ISOW层内释放（σ0> 27.80 kg m−3），并根据它们的输出路径进行分类：越过雷克雅内斯脊，通过查理吉布斯断裂带（CGFZ）或进入西欧盆地。研究表明，雷克雅内斯海岭上空的出口在2.5年至10年的时间尺度上表现出变化，并且与北大西洋洋流（NAC）波动迫使中深度向北输送到冰岛盆地密切相关，这表明与大尺度环流动力学有关。通过CGFZ的出口具有2.5-5年的变率特征，并受CGFZ内向东流动的NAC的经向位置的影响，该位置可以阻止ISOW出口并使颗粒进入WEB。输出路径显示出明显的深度依赖性，例如浅层受地表环流的影响更大，而深层则更容易受到地形转向的影响，这一结果得到了在opsnap活动期间部署的RAFOS浮子的观测结果的证实。综上所述，这些发现说明了ISOW输出路径的高度可变性，并有助于越来越多的证据挑战冰岛盆地单一主导路径的概念。
{"title":"Interannual variability and depth-dependence in pathways of Iceland–Scotland Overflow Waters exiting the Iceland Basin","authors":"Ali Johnson Exley , Amy Bower , Xiaobiao Xu , Sijia Zou , Anna Pinckney , Heather Furey","doi":"10.1016/j.pocean.2025.103662","DOIUrl":"10.1016/j.pocean.2025.103662","url":null,"abstract":"<div><div>Iceland–Scotland Overflow Water (ISOW), a dense water mass formed in the Nordic Seas, spills into the Iceland Basin through the Iceland-Faroe Ridge and Faroe Shetland Channel before propagating southwestward along the eastern flank of the Reykjanes Ridge as a deep boundary current, contributing to the lower limb of the Atlantic Meridional Overturning Circulation. Recent work has demonstrated that pathways of ISOW out of the Iceland Basin are complex and variability has not been explored on interannual and longer timescales. In this study, we use the basin-scale, eddy-rich (1/12°), 40-year Atlantic Hybrid Coordinate Ocean Model (HYCOM) simulation to investigate the variability in ISOW export pathways. Simulated Lagrangian particles are released within the ISOW layer (<span><math><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>></mo></mrow></math></span> 27.80 kg m<sup>−3</sup>) at two locations along the eastern flank of the Reykjanes Ridge and classified according to their export pathway: over the Reykjanes Ridge, through the Charlie Gibbs Fracture Zone (CGFZ) or into the Western European Basin (WEB). We show that export over the Reykjanes Ridge exhibits variability on timescales from 2.5 years to decadal and is strongly correlated with mid-depth northward transport into the Iceland Basin forced by fluctuations in the North Atlantic Current (NAC), suggesting a link to large-scale gyre dynamics. Export through the CGFZ is characterized by variability of 2.5–5 years and is influenced by the meridional position of the eastward-flowing NAC within the CGFZ, which can block ISOW export and divert particles into the WEB. Export pathways are shown to exhibit a significant depth-dependence such that shallower layers are more strongly impacted by the surface circulation while deeper layers are more subject to topographic steering, results that are corroborated by utilizing observations from RAFOS floats deployed during the OSNAP campaign. Together, these findings illustrate the high-degree of variability in pathways of ISOW export and contributes to the growing body of evidence that challenges the notion of a single, dominant pathway out of the Iceland Basin.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103662"},"PeriodicalIF":3.6,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894968","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}
Pub Date : 2025-12-26DOI: 10.1016/j.pocean.2025.103657
Stefanie Kaiser , Anna M. Jażdżewska , Sarah Gerken , Anne Helene S. Tandberg , Chih-Lin Wei , Davide Di Franco , Hanieh Saeedi , Hannah Owens , Henry Knauber , Emma Palacios Theil , Angelika Brandt , Pedro Martinez Arbizu , Jens Oldeland
Accelerating climate change driven by greenhouse gas emissions is profoundly impacting marine biodiversity. Some species are shifting their geographic ranges toward more favourable environments, while others lose suitable habitat and face extinction. We examined the effects of climate change on selected benthic peracarid species (Amphipoda, Cumacea, and Isopoda) in the Pacific Arctic, Pacific Subarctic, and North Pacific temperate ecosystems—regions characterized by environmental sensitivity and unique topography. Using Maximum Entropy (MaxEnt) modelling, we identified key environmental drivers of species occurrence and projected horizontal and vertical shifts until 2050 and 2100 under RCP 2.6 and 8.5 scenarios. We further analysed how ecological traits such as diet, mobility, and life habit correlate with distributional responses. While most species shifted northward, some exhibited unexpected directional changes, likely due to regional differences in climate velocity, environmental change, and species-specific responses. Temperature emerged as a primary determinant for many species, with dissolved oxygen and salinity also playing critical roles. Our findings indicate that traits—particularly diet and bathymetric distribution—affect potential habitat expansions or contractions, categorizing species as potential “winners” or “losers.” Despite challenges including deep-sea data limitations and complex trait interactions, our study provides vital insights into future peracarid distributions. These results underscore the need for refined predictive models and targeted conservation strategies to enhance ecosystem resilience and sustainable resource management in a warming ocean.
{"title":"Beyond temperature: predictive modelling of range shifts in benthic peracarids across the northern North Pacific under future climate scenarios","authors":"Stefanie Kaiser , Anna M. Jażdżewska , Sarah Gerken , Anne Helene S. Tandberg , Chih-Lin Wei , Davide Di Franco , Hanieh Saeedi , Hannah Owens , Henry Knauber , Emma Palacios Theil , Angelika Brandt , Pedro Martinez Arbizu , Jens Oldeland","doi":"10.1016/j.pocean.2025.103657","DOIUrl":"10.1016/j.pocean.2025.103657","url":null,"abstract":"<div><div>Accelerating climate change driven by greenhouse gas emissions is profoundly impacting marine biodiversity. Some species are shifting their geographic ranges toward more favourable environments, while others lose suitable habitat and face extinction. We examined the effects of climate change on selected benthic peracarid species (Amphipoda, Cumacea, and Isopoda) in the Pacific Arctic, Pacific Subarctic, and North Pacific temperate ecosystems—regions characterized by environmental sensitivity and unique topography. Using Maximum Entropy (MaxEnt) modelling, we identified key environmental drivers of species occurrence and projected horizontal and vertical shifts until 2050 and 2100 under RCP 2.6 and 8.5 scenarios. We further analysed how ecological traits such as diet, mobility, and life habit correlate with distributional responses. While most species shifted northward, some exhibited unexpected directional changes, likely due to regional differences in climate velocity, environmental change, and species-specific responses. Temperature emerged as a primary determinant for many species, with dissolved oxygen and salinity also playing critical roles. Our findings indicate that traits—particularly diet and bathymetric distribution—affect potential habitat expansions or contractions, categorizing species as potential “winners” or “losers.” Despite challenges including deep-sea data limitations and complex trait interactions, our study provides vital insights into future peracarid distributions. These results underscore the need for refined predictive models and targeted conservation strategies to enhance ecosystem resilience and sustainable resource management in a warming ocean.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103657"},"PeriodicalIF":3.6,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145844678","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}
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