Progress in Oceanography最新文献

{"title":"Connection of central South China Sea current variability with tropical Rossby waves in the western North Pacific","authors":"Mac Euan D. Malugao ,&nbsp;Sen Jan ,&nbsp;Ming-Huei Chang ,&nbsp;Tung-Yuan Ho ,&nbsp;Yiing Jang Yang","doi":"10.1016/j.pocean.2025.103481","DOIUrl":"10.1016/j.pocean.2025.103481","url":null,"abstract":"<div><div>This study investigates the connection between the current velocity variations in the central South China Sea (SCS) and westward-propagating tropical Rossby waves in the western North Pacific, using satellite altimeter observations and coastal tide-gauge data supplemented by numerical modeling. This work is focused on the dynamic link between the intraseasonal velocity oscillations observed in the central-eastern SCS in summer 2017 and the Rossby waves that impinge on the east coast of the Philippine Archipelago. Low-pass-filtered satellite sea level anomaly (SLA) data and coastal sea level records suggest that Rossby waves can propagate into the Celebes Sea and Sulu Sea, eventually reaching the central SCS. A three-dimensional, primitive equation model shows that Rossby wave-associated SLA signals transmit through the Philippine Archipelago to the central SCS via the Celebes Sea-Sibutu Passage-Sulu Sea-Mindoro Strait route, with modeled SLA propagation timings that are consistent with the observations. As the Rossby wave reaches the eastern Philippines, approximately one-third of the incident wave energy from a meridional section east of the Philippines (132°E, between 2°N and 15°N) is transmitted into the Celebes Sea and Luzon Strait, whereas approximately two-thirds of the energy is dissipated, transformed, or reflected along the Philippine coast. Approximately 15 % of the energy entering the Celebes Sea passes through the Sibutu Passage into the Sulu Sea, and ∼10 % exits the Mindoro Strait into the central SCS. These suggest that 2−5 % of the incident energy from the western North Pacific transmitted into the central SCS and influences sea level and velocity variations there.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"235 ","pages":"Article 103481"},"PeriodicalIF":3.8,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143885925","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":"Linking physical processes to biological responses: Interdisciplinary observational insights into the enhanced biological productivity of the Cape Verde Archipelago","authors":"Florian Schütte ,&nbsp;Anna Christina Hans ,&nbsp;Marco Schulz ,&nbsp;Rebecca Hummels ,&nbsp;Olivier Assokpa ,&nbsp;Peter Brandt ,&nbsp;Rainer Kiko ,&nbsp;Arne Körtzinger ,&nbsp;Björn Fiedler ,&nbsp;Tim Fischer ,&nbsp;Elizandro Rodrigues ,&nbsp;Henk-Jan Hoving ,&nbsp;Helena Hauss","doi":"10.1016/j.pocean.2025.103479","DOIUrl":"10.1016/j.pocean.2025.103479","url":null,"abstract":"<div><div>The Cape Verde Archipelago (CVA) is a hotspot of biological productivity in the oligotrophic central North Atlantic, supporting a highly diverse ecosystem. Twenty years of interdisciplinary observational data are used to investigate the primary physical processes driving this productivity and their impacts on the composition of biological life across the food web of the CVA. Three dominant physical processes are identified: <strong><em>I.</em></strong> <em>Atmospheric forced island wakes:</em> Wind interactions with the topography of Santo Antão and Fogo generate local wind shear, creating surface-intensified, productive eddy fields that extend several island diameters downstream. <strong><em>II.</em></strong> <em>Interaction of remotely generated mesoscale eddies with the CVA:</em> Nitrate-rich eddies generated off the coast of West Africa interact with the CVA by colliding with the eastern islands, or by passing near shallow bathymetry. This interaction enhances submesoscale activity, likely driven by unbalanced mesoscale flow, leading to hotspots of vertical advection and mixing. Our observations indicate, in addition, interactions between passing eddies and island-induced processes, such as an elevated internal wave field and wind curl in lee of the islands. This results in up to a tenfold increase in mixing within near-island eddies. <strong><em>III.</em></strong> <em>Interactions of tidal flows and internal waves with the CVA:</em> Internal wave breaking at specific hotspots, such as south of Santo Antão, leads to elevated vertical mixing rates, up to 1000 times higher than at reference points. The mean internal wave field in the CVA is over twice as energetic as in the open ocean, and even stronger at distinct hotspots. These three physical processes, although different in nature, all enhance upward nitrate flux, thereby promoting significantly higher chlorophyll concentrations. This, in turn, forms the foundation of the local pelagic food web, including mesozooplankton and micronekton, such as mesopelagic fishes, whose abundance increase three- to tenfold at these local hotspots. The composition of the biological communities is highly diverse and varies across different regions and physical processes. Annual landings of mackerel and tuna on the CVA, as well as the abundance of humpback whales, are positively correlated with annual mean chlorophyll concentrations. Overall, our study reveals a strong correlation between nitrate supply to the euphotic zone, driven by various physical processes, and species abundance throughout the food web, extending to large predators. These findings underscore the crucial role of local physical processes in shaping the structure of marine communities from lower to higher trophic levels, explaining biological diversity in the marine environment of the CVA and beyond.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"235 ","pages":"Article 103479"},"PeriodicalIF":3.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947166","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":"Mapping internal lee wave generation and dissipation in the deep South China sea","authors":"Zhenhua Xu ,&nbsp;Ji Li ,&nbsp;Peiwen Zhang ,&nbsp;Jia You ,&nbsp;Jianping Gan","doi":"10.1016/j.pocean.2025.103474","DOIUrl":"10.1016/j.pocean.2025.103474","url":null,"abstract":"<div><div>Abyssal mixing induced by internal wave breaking has been proposed as an essential process that maintains and modulates the deep cyclonic circulation and meridional overturning circulation in the South China Sea (SCS). Previous studies have primarily focused on internal tides, leaving limited exploration on internal lee waves and their roles in mixing the SCS. This study represents the first basin-scale estimation of the lee-wave energy flux from the geostrophic flow and exploration of lee-wave-induced mixing in the SCS. Utilizing an improved spectra method with the synthetic full-scaled bathymetry, lee wave generation is estimated employing Bell theory with the outputs from the China Sea Multi-Scale Ocean Modeling System. The Luzon Strait (LS) features the strongest lee wave generation, reaching up to 19.7 GW. In the SCS interior, the total energy flux is estimated at 1.3 GW, with 70% occurring in the deep basin. In the basin area, energy flux from the mean flow surpasses that from eddy flow, whereas in the marginal area, the dominant energy flux is from eddy flow. This study reveals seasonal variation in lee wave generation, closely related to the seasonality of the deep-water overflow from the LS. The mixing driven by lee waves is found comparable with that driven by internal tides in the deep SCS basin. This study emphasizes the potentially significant lee wave energy and induced mixing in the deep SCS basin, which should be well-mapped and parameterized in ocean models for a better characterization of multiscale dynamics and energetics in the SCS.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"235 ","pages":"Article 103474"},"PeriodicalIF":3.8,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879489","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":"Kinorhyncha community in the Aleutian Trench (North Pacific Ocean) with the description of a new Cristaphyes species (Allomalorhagida, Pycnophyidae)","authors":"Nuria Sánchez ,&nbsp;Frederic Bonk ,&nbsp;Alberto González-Casarrubios","doi":"10.1016/j.pocean.2025.103475","DOIUrl":"10.1016/j.pocean.2025.103475","url":null,"abstract":"<div><div>Several species of trench-dwelling meiofaunal animals, including Kinorhyncha, have been described in recent years; however, our knowledge on kinorhynchs inhabiting abyssal and even hadal depths is still extremely scarce. In the present study, we explore the Kinorhyncha community of the Aleutian Trench, North Pacific Ocean, an under-sampled region in terms of meiofauna. As a result, a new species of <em>Cristaphyes</em> inhabiting abyssal and hadal depths of the trench is described. <em>Cristaphyes unangax</em> sp. nov. is characterized by the presence of middorsal processes on segments 1 – 10, with the last one extending well-beyond the posterior margin of the trunk. <em>Cristaphyes unangax</em> sp. nov. thus becomes the fourth hadal species described within the phylum Kinorhyncha. In terms of biodiversity, abundance of adult kinorhynchs remains relatively low along the trench’s depth gradient (c.a. 3.500 – 7.200 m), except at two sites: one at the axis and another at the slope. The higher abundance at the axis aligns with patterns in other trenches, where organic matter accumulation enhances microbial activity, supporting meiofaunal communities. The elevated specimens at the slope station, located at abyssal depth, may result from Aleutian upwelling currents or trench terraces that facilitate food deposition. The Kinorhyncha community in the Aleutian Trench is dominated by <em>Echinoderes ultraabyssalis</em> and includes another nine species, many shared with the North Pacific and Arctic. These findings suggest that meiofauna in the North Pacific can disperse across bathymetric barriers, potentially linking the Aleutian and Kuril-Kamchatka trenches. Additionally, the Aleutian Trench may serve as a migration corridor for meiofauna between the North Pacific and Arctic, aided by strong bottom currents.</div><div><strong>Zoobank</strong>: urn:lsid:zoobank.org:pub:56D1BA0B-3D9F-4547-84BC-C9BAFCA1D220</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"236 ","pages":"Article 103475"},"PeriodicalIF":3.8,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084481","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":"Presence of two eddies in close proximity drives large spatial and temporal heterogeneity in the euphotic zone","authors":"Simon Ramondenc ,&nbsp;Richard S. Lampitt ,&nbsp;Maria Fredrika Norrbin ,&nbsp;Anna Belcher ,&nbsp;Wilken-Jon von Appen ,&nbsp;Morten H. Iversen","doi":"10.1016/j.pocean.2025.103476","DOIUrl":"10.1016/j.pocean.2025.103476","url":null,"abstract":"<div><div>Oceanic mesoscale structures, such as eddies, play a fundamental role in ocean circulation, ocean biogeochemical cycles and plankton ecology. They cause lateral and vertical advection, as well as interact with vertical mixing, which is predicted to promote episodic fluxes of macronutrients to the surface ocean. However, the interactions between mesoscale eddies can generate submesoscale fronts and filaments occurring over short temporal and spatial scales and thus their impact on ocean biogeochemistry has been difficult to characterize. During an expedition to the Porcupine Abyssal Plain (PAP) site in the Northeast Atlantic in June 2013, we studied the interface between a cyclonic and an anticyclonic eddy, measuring nutrient and chlorophyll-a concentrations, zooplankton abundance and community structure, and marine snow aggregate abundance and sinking velocities. We observed that eddy rotation and a storm event induced, respectively, lateral stirring and vertical mixing of the two distinct water masses, driving spatial and temporal biogeochemical heterogeneity at the PAP site. Furthermore, we observe that diel and vertical variations in aggregate type and abundance were closely linked to the vertical distribution and abundance of zooplankton, suggesting that zooplankton were the main gatekeepers of carbon flux. Our findings suggest that the interactions between mesoscale structures could significantly modify organic carbon export, as well as provide sustenance for higher trophic levels, processes that have implications for fisheries and global climate.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"235 ","pages":"Article 103476"},"PeriodicalIF":3.8,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868956","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":"Significance of temperature and salinity in the dynamics of diatoms and dinoflagellates along the coastal Yellow Sea","authors":"Chenshi Weng ,&nbsp;Dongsheng Ding ,&nbsp;Qian Yang ,&nbsp;Lin Zhu ,&nbsp;Jun Sun ,&nbsp;Keming Qu ,&nbsp;Zhengguo Cui ,&nbsp;Yuqiu Wei","doi":"10.1016/j.pocean.2025.103478","DOIUrl":"10.1016/j.pocean.2025.103478","url":null,"abstract":"<div><div>Diatoms and dinoflagellates are two typical functional groups of phytoplankton, which account for a major part of global primary production and play an important role in ecosystem processes and biogeochemical cycles. It is well known that the dynamics of diatoms and dinoflagellates in the ocean are mainly driven by changes in hydrological conditions related to climate change and human activities. However, little is known about their ability to adapt to changing ocean environments, making it difficult to predict whether and how they will adapt. Analysis of field data from the coastal Yellow Sea (2021–2023) showed that temperature and salinity changes, driven by seasonal variations, notably affected the dynamics of diatoms and dinoflagellates. Moreover, the seasonal dynamics of these two groups exhibited distinct responses to temperature, salinity, and their interactions. Specifically, diatoms exhibited greater heat resistance than dinoflagellates, but were more sensitive to salinity changes, often dominating during the warmer, less saline summer and autumn seasons. In contrast, dinoflagellates, due to their nutritional strategies, showed greater tolerance to salinity changes and often co-dominated with diatoms under high salinity conditions. Overall, changes in temperature and salinity had a large impact on diatoms and dinoflagellates in coastal Yellow Sea, albeit with different relationships. Therefore, future research should focus on the long-term effects of combined temperature and salinity changes, as well as the potential influence of other environmental variables such as nutrient availability.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"234 ","pages":"Article 103478"},"PeriodicalIF":3.8,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854840","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 stable-carbon-isotope-based constraint of bulk particulate organic carbon dynamics and budgets in the Yellow Sea: Combining field surveys and isotope fractionation modeling","authors":"Cong-cong Guo ,&nbsp;Shu Yang ,&nbsp;Qing-shan Luan ,&nbsp;Qian-qian Liu ,&nbsp;Zi-chen Liu ,&nbsp;Wei-dong Zhai","doi":"10.1016/j.pocean.2025.103477","DOIUrl":"10.1016/j.pocean.2025.103477","url":null,"abstract":"<div><div>The isotopic composition of POC (δ¹³C_POC) serves as a critical tracer for marine carbon dynamics. Its traditional applications usually assume a fixed δ¹³C value for marine phytoplankton (δ¹³C_phyto) of − 20 ± 1 ‰, overlooking spatiotemporal variabilities in phytoplankton carbon isotope fractionation (<em>ε</em>_P). This study quantifies <em>ε</em>_P-mediated δ¹³C_POC variations in the Yellow Sea – a temperate shelf sea characterized by seasonal stratification, intense diatom blooms, and terrestrial inputs – by coupling isotope fractionation models (passive CO₂aq diffusion vs. active HCO₃^– transport) with multi-season δ¹³C measurements of Dissolved Inorganic Carbon (DIC) and δ¹³C_POC. During algal bloom periods, δ¹³C_POC values were relatively heavier (−20 ± 1 ‰), driven by active HCO₃^– uptake under low CO₂aq concentrations ([CO₂aq]). Strong agreement between δ¹³C_POC and modeled δ¹³C_phyto values confirmed compositional similarity between POC and algal biomass, with <span><math><mrow><msub><mrow><mi>ε</mi></mrow><mrow><mi>P</mi></mrow></msub></mrow></math></span> exhibiting significant covariation with [CO₂aq]. In non-bloom periods, lighter δ¹³C_POC values (from − 26 to − 24 ‰) dominated surface layers, with even more depleted signatures (&lt;−26 ‰) occurred in the Deep Chlorophyll Maximum (DCM) and middle layers. Although detritus inputs caused deviations of δ¹³C_POC from modeled δ¹³C_phyto values, temperature-dependent correlations still revealed <span><math><mrow><msub><mrow><mi>ε</mi></mrow><mrow><mi>P</mi></mrow></msub></mrow></math></span>-related isotopic dynamics in POC. This research underscores the necessity of using environment-specific δ¹³C_phyto values to refine POC budget estimates, reducing flux uncertainties by 20–30 % and minimizing isotopic errors to &lt; 1 ‰ across different timescales. This work establishes a framework for incorporating δ¹³C_phyto plasticity into coastal carbon models, resolving long-standing paradoxes of isotopically light POC (&lt;−26 ‰) in marine-dominated systems and advancing high-resolution carbon flux estimates in marginal seas.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"236 ","pages":"Article 103477"},"PeriodicalIF":3.8,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144071858","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":"Seasonal dissolved oxygen gas exchange in the California Current Upwelling System","authors":"A.S. Ren ,&nbsp;D.L. Rudnick ,&nbsp;D.P. Nicholson","doi":"10.1016/j.pocean.2025.103473","DOIUrl":"10.1016/j.pocean.2025.103473","url":null,"abstract":"<div><div>Eastern boundary current systems are known for seasonal upwelling that brings water from below the mixed layer to the surface. The process deoxygenates the water column by bringing lower-dissolved oxygen water closer to the surface and oxygenates the water column by driving primary productivity due to the injection of nutrients from deep waters. Here, an observational dataset of 5 years of dissolved oxygen, temperature, and salinity measured to 500 m and from the coast to around 400 km offshore is used to study the seasonal evolution of air-sea exchange of oxygen in an upwelling region. The data were collected as part of the California Underwater Glider Network (CUGN) which monitors transect line 66.7 off of Monterey Bay, CA, transect line 80.0 off of Point Conception, CA, and transect line 90.0 off of Dana Point, CA year-round. A narrow band of coastal oxygen undersaturation drives dissolved oxygen uptake by the ocean in spring and summer, while in winter dissolved oxygen uptake predominates due to more widespread but less intense oxygen undersaturation. Oxygen outgassing occurs offshore of the nearshore uptake band in spring and summer, driven by warming and primary productivity, such that the cumulative net oxygen gas exchange integrated seaward from shore reaches zero once around one hundred kilometers from the coast. Ventilation of the upper ocean is observed as a result of shoaling isopycnals in the upwelling season. The balance between outgassing and uptake is such that the central and southern California Current System is a region of net outgassing of oxygen for a region from the coast to 400 km, 365 km, and 530 km for lines 66.7, 80.0, and 90.0 respectively. Competing factors causing uptake and outgassing and the seaward extent of the domain determine whether an upwelling zone is a net source or sink of oxygen gas.</div></div><div><h3>Plain Language Summary</h3><div>The oceanography of coastal California is such that a seasonal vertical and offshore movement of water in the nearshore 50 km reduces the dissolved oxygen concentration of the water. The dissolved oxygen changes in the ocean were observed with autonomous underwater vehicles that allowed scientists to observe seasonal changes. Dissolved oxygen gas was found to enter the ocean in the coastal region during times of upwelling while it was released from the ocean further offshore. Some dissolved oxygen that entered the ocean surface layer found its way to deeper waters. The amount of dissolved oxygen gas released from the surface ocean compensated for the amount of oxygen uptake that occurred. The region from the coast to around 400 km from shore released oxygen gas to the atmosphere overall.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"236 ","pages":"Article 103473"},"PeriodicalIF":3.8,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099777","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 role of the Atlantic-Ionian stream in the long-term variability of the surface circulation in the Northern Ionian Sea: Results from a hindcast simulation","authors":"E. Napolitano ,&nbsp;A. Carillo ,&nbsp;M.V. Struglia ,&nbsp;R. Iacono ,&nbsp;M. Palma ,&nbsp;G.L. Eusebi Borzelli ,&nbsp;G. Sannino","doi":"10.1016/j.pocean.2025.103472","DOIUrl":"10.1016/j.pocean.2025.103472","url":null,"abstract":"<div><div>We examine the long-term variability of the near-surface circulation of the Ionian Sea. Our analysis primarily focuses on a high-resolution hindcast simulation of the Mediterranean dynamics from 1981 to 2010. This time period is significant as it includes a notable near-surface circulation reversal in the Northern Ionian Sea (NIS), which shifted from anticyclonic to cyclonic at the end of 1997. This transition has been previously documented by altimeter data and Copernicus reanalysis. Our hindcast simulation accurately captures this change. Here we examine the temporal and spatial scales of the near-surface circulation during the transition and investigate the factors contributing to the observed variability of the basin dynamics, including local wind-stress, deep-water density anomalies, and the lateral current associated with the Atlantic Ionian Stream (AIS). We find that while wind stress does play a role, the primary factor driving long-term variability in the NIS near-surface circulation is the AIS. During the late 1980s to mid-1990s, the AIS was weak and local cyclonic winds were also weak, allowing the AIS to enter the NIS along the coasts of Sicily. This led to the formation of a wide anticyclonic cell in the NIS. From the mid-1990s to 2010, the AIS was stronger and, favored by stronger cyclonic winds, detached from the coasts of Sicily heading directly towards the Levantine basin without penetrating the NIS. This process led to the formation of a wide cyclonic cell over the NIS. These results highlight the role of the AIS in controlling the circulation of the NIS.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"234 ","pages":"Article 103472"},"PeriodicalIF":3.8,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833977","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":"Trophic niche shifts in Japanese anchovy, Engraulis japonica, during ontogenetic migration in a temperate continental shelf system","authors":"Changseong Kim ,&nbsp;Jaebin Jang ,&nbsp;Jaesik Yang ,&nbsp;Jang Han Choi ,&nbsp;Hee Yoon Kang ,&nbsp;Seong Yong Moon ,&nbsp;Ho Young Soh ,&nbsp;Heeyong Kim ,&nbsp;Chang‑Keun Kang","doi":"10.1016/j.pocean.2025.103471","DOIUrl":"10.1016/j.pocean.2025.103471","url":null,"abstract":"<div><div>Understanding the mechanisms driving ontogenetic niche shifts in fishes has predominantly focused on dietary changes in large predatory migrants. This study investigates trophic niche dynamics in a small, pelagic migratory fish, the Japanese anchovy (<em>Engraulis japonicus</em>). By mapping migratory paths across varied oceanographic regions on a temperate continental shelf of Korean waters, we quantified changes in the trophic niche using δ¹³C and δ¹⁵N values across different ontogenetic stages (juvenile, subadult, and adult). We hypothesized that biological and ecological processes associated with fish ontogeny and migration cause trophic niche shifts. Results showed that juvenile anchovies had a narrow trophic niche, which expanded as they matured, indicating a shift from specialist to generalist feeding habits, unlike many large predatory fishes. Limited isotopic niche overlap among life stages suggested niche partitioning within inshore habitats where all stages coexist. Morphological and behavioral traits related to life history likely drive these feeding modes and prey use changes. Isotopic profiles varied with migratory routes, reflecting spatial variations in zooplankton isotope baselines. Adults showed higher δ¹³C in the southern offshore (Yangtze River Diluted Water area) and lower δ¹⁵N in the eastern offshore (Tsushima Warm Current area) compared with inshore (South Korea Coastal Water area), resulting in distinct isotopic niches. This isotopic variation is likely due to differing lower trophic-level processes and zooplankton assemblages, as supported by our dietary mixing model. Our findings highlight that ontogenetic changes in feeding habits and adaptive responses to prey availability along their migratory paths facilitate trophic niche shifts in Japanese anchovy.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"234 ","pages":"Article 103471"},"PeriodicalIF":3.8,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769094","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}