Journal of Marine Systems最新文献

{"title":"Frontlines of productivity: A remote sensing view into the seasonal mosaics of the Southwest Atlantic Ocean","authors":"Martín J. Rivarossa ,&nbsp;Valeria A. Guinder ,&nbsp;E. Marcelo Acha","doi":"10.1016/j.jmarsys.2025.104176","DOIUrl":"10.1016/j.jmarsys.2025.104176","url":null,"abstract":"<div><div>Frontal systems associated with continental shelf breaks rank among the most biologically productive marine environments, supporting rich food webs and key fisheries. In the Southwestern Atlantic, the Patagonian Shelf Break Front (PSBF; 35°S–55°S) is a globally significant hotspot of primary production, yet its spatial extent and seasonal variability remain poorly understood. Using a 20-year MODIS-Aqua chlorophyll-a (Chl-a) climatology, we delineated the productive region influenced by the PSBF – termed here the Chlorophyll Front - and analyzed its seasonal dynamics. Unsupervised k-means clustering of annual Chl-a cycles revealed five regions with distinct phytoplankton phenological patterns, organized along a latitudinal gradient. Phenological metrics at both region and pixel scales showed clear patterns in bloom initiation, intensity, and duration. Notably, a bimodal seasonal pattern - with spring and summer peaks - was observed in ∼60 % of the area. In most of the ecosystem, the cumulative duration of phytoplankton blooms throughout the phenological cycle exceeded 160 days per year, placing this ecosystem among those with the longest total bloom durations in the global ocean. Maximum annual Chl-a integration occurred in northern regions, aligning with the most dense benthic beds of the Patagonian scallop, a key fishery resource in the area. The spatial arrangements of key phenological metrics appears to be influenced by canonical environmental drivers such as seasonal light availability and water column stratification, while also reflecting influence of more stochastic forces like upwelling intensity and wind variability. The resulting bioregionalization and phenological metrics parametrization offer a robust framework to monitor change and inform spatially explicit management. By unveiling the structure and functioning of this globally relevant frontal system, our study provides critical baselines for understanding the vulnerability of oceanic fronts to climate change and anthropogenic pressures.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104176"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939026","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":"Physical structures associated with wind-induced mixing in Tokyo Bay","authors":"Haruki Itozu ,&nbsp;Eiji Masunaga","doi":"10.1016/j.jmarsys.2025.104173","DOIUrl":"10.1016/j.jmarsys.2025.104173","url":null,"abstract":"<div><div>Wind stress and river discharge are key drivers of mixing and estuarine circulation, which strongly affect dissolved oxygen (DO) dynamics. Despite extensive studies on water circulation and hypoxia in Tokyo Bay, detailed physical processes in Tokyo Bay are not well understood. This study assessed mixing in an enclosed coastal sea in the inner part of Tokyo Bay using observational records from five monitoring stations. Our results indicate that the horizontal Richardson number, calculated from wind stress and horizontal buoyancy gradients, effectively explains vertical mixing and stratification. The horizontal buoyancy gradient between the inner and middle parts of Tokyo Bay can be inferred from the winds along the channel except during coastal upwelling events. Furthermore, we found a robust relationship between hypoxia and high-density water in the bottom boundary layer, which was modulated by the mixing conditions in the bay. This study provides new insights into coastal mixing processes associated with buoyant river discharge in areas where wind forcing is dominant.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104173"},"PeriodicalIF":2.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840537","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":"Local wind and remote forcing effects on exchange flows at the entrance to a subtropical estuary","authors":"Juan Torres-Córdoba ,&nbsp;Jorge Armando Laurel-Castillo ,&nbsp;Arnoldo Valle-Levinson ,&nbsp;Maria F. Gastelu-Barcena","doi":"10.1016/j.jmarsys.2025.104170","DOIUrl":"10.1016/j.jmarsys.2025.104170","url":null,"abstract":"<div><div>This study investigates how local wind and remote forcing influence subtidal exchange flows at the entrance to a subtropical estuary, the Peace River estuary, Florida, being a case study. Moored acoustic Doppler current profiler (ADCP) measurements were analyzed in combination with Empirical Orthogonal Function (EOF) and wavelet coherence analysis to identify distinct circulation responses to these forcings. Local wind forcing produced bidirectional circulation characterized by surface flows aligned with the wind and bottom flows opposing it. In contrast, remote forcing, representing large-scale barotropic disturbances propagating from the coastal ocean, produced predominantly unidirectional flows. The first two EOF modes captured these responses, explaining over half of the subtidal flow variance (65 %). Wavelet coherence analysis revealed a temporal coupling between Mode 1 and local wind stress, and between Mode 2 and remotely driven volume transport. These findings are among the few observational efforts that support theoretical results for local wind and remote forcing on estuarine exchange flows. As such, they enhance our understanding of wind-driven flow processes in estuarine systems and the connectivity between estuarine and shelf circulation.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104170"},"PeriodicalIF":2.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798346","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":"Impact of extreme weather events on pelagic cyanobacterial communities: an in situ mesocosm study in the Gulf of Finland","authors":"Mariano Santoro ,&nbsp;Mari Vanharanta ,&nbsp;Cristian Villena-Alemany ,&nbsp;Christiane Hassenrück ,&nbsp;Martin Hagemann ,&nbsp;Hans-Peter Grossart ,&nbsp;Kasia Piwosz ,&nbsp;Kristian Spilling ,&nbsp;Matthias Labrenz","doi":"10.1016/j.jmarsys.2025.104174","DOIUrl":"10.1016/j.jmarsys.2025.104174","url":null,"abstract":"<div><div>Cyanobacteria play a critical role in regulating carbon, nitrogen, and phosphorus cycles in the Baltic Sea, seasonally forming extensive blooms under nitrogen-limited conditions in summer. Understanding their responses to environmental disturbances is crucial in the Baltic Sea where increasing and persistent surface water temperature anomalies were observed over the past two decades. During a 17-day mesocosm experiment in the southwestern Finnish archipelago (Gulf of Finland) designed to investigate microbial community dynamics under varying nutrient conditions, the unexpected occurrence of a natural disturbance event created a unique opportunity to assess the effects of pronounced physical changes on cyanobacterial dynamics. The natural disturbance overshadowed the expected effects of the nutrient treatments, which was especially evident for cyanobacteria. The picocyanobacterium <em>Cyanobium</em> spp. emerged as the dominant species throughout the study, particularly following the occurrence of the near gale wind-driven rainfall, likely due to its adaptability to rapid environmental changes. Conversely, the filamentous cyanobacteria <em>Aphanizomenon</em> spp. and <em>Pseudoanabaena</em> spp. thrived under stable conditions. These findings highlight the resilience of picocyanobacteria to environmental fluctuations and their primary role in driving cyanobacterial community dynamics during summer in the Baltic Sea, where natural perturbations are expected to occur with increasing frequency due to climate change.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104174"},"PeriodicalIF":2.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798345","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":"Response of ocean surface currents to the summer monsoon onset in the northern Indian Ocean","authors":"Yue Yin ,&nbsp;Kuiping Li","doi":"10.1016/j.jmarsys.2025.104172","DOIUrl":"10.1016/j.jmarsys.2025.104172","url":null,"abstract":"<div><div>The surface currents in the northern Indian Ocean (IO) are profoundly influenced by the monsoon cycle. However, the systematic response of these currents to the abrupt onset of the summer monsoon remains insufficiently understood. Based on a surface current model, this study examines the evolution and dynamics of surface currents in relation to the climatological two-step monsoon onset in the northern IO. During the Bay of Bengal (BoB) monsoon onset, strong equatorial westerlies trigger downwelling equatorial Kelvin waves, which drive the spring Wyrtki Jet (WJ) to its peak phase. Simultaneously, intensified southwest winds south of Sri Lanka establish the Southwest Monsoon Current (SMC). As the equatorial Kelvin waves reach the eastern boundary, they give rise to westward-propagating Rossby waves, which further strengthen the current when traveling across the SMC region. Part of the equatorial Kelvin wave energy is converted into coastal Kelvin waves that propagate along the inner boundary of the BoB, leading to the weakening of the East Indian Coastal Current (EICC). The poleward Somali Current (SC) strengthens quickly during the BoB monsoon onset and intensifies further with the Arabian Sea (AS) monsoon onset, which is primarily driven by local wind forcing associated with both onset processes. The Great Whirl (GW) forms during the AS monsoon onset, coinciding with the second intensification of the SC. Local wind forcing also plays a crucial role in strengthening the GW after the AS monsoon onset. Understanding the response patterns and physical mechanisms of surface currents during the summer monsoon onset enhances our knowledge of monsoon-ocean interactions in the IO.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104172"},"PeriodicalIF":2.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797908","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":"Drastic changes in macrofaunal communities of intertidal boulder fields habitat during the last decade in the south of the Bay of Biscay","authors":"Léa Marmion ,&nbsp;Marie-Noëlle de Casamajor ,&nbsp;Muriel Lissardy ,&nbsp;Florian Ganthy ,&nbsp;Laura Huguenin ,&nbsp;Claire Kermorvant ,&nbsp;Yann Lalanne","doi":"10.1016/j.jmarsys.2025.104171","DOIUrl":"10.1016/j.jmarsys.2025.104171","url":null,"abstract":"<div><div>The cumulative effects of environmental and anthropogenic pressures on marine environments are endangering the biocenoses that inhabit them. Identifying and understanding the impacts of global changes are key challenges for maintaining habitats in a good ecological state and require the use of standardized monitoring and reliable ecological indicators.</div><div>During last decade, as part of various research programs, macrofaunal communities were inventoried in the boulder fields in the Southeastern Bay of Biscay, in an area devoid of fishing pressure. During two time periods, 2015-2016 and 2021-2022, mobile and sessile macrofauna of the upper and lower mediolittoral zones were sampled annually between April and June following a stratified random sampling design. The results reveal significant spatio-temporal changes over the study period, with a transitional year in 2020, that may be associated with the annual appearance of toxic blooms of the microalga <em>Ostreopsis</em>. Shifts in biodiversity, functional structure and the status of indicator species of the habitat were observed, with a marked decline or even local disappearance of several species. From a functional perspective, the decline in grazer abundance was striking particularly in the upper zone. While other guilds in the upper zone showed limited and non-significant changes, the lower zone revealed a broader and significant decline across multiple trophic groups, reflecting a more generalized functional reorganization and supporting the shift toward a new ecosystem state. This ecological shift appears to coincide with long-term changes in environmental parameters (e.g. water temperature, salinity) and may signal a transition toward a novel community state.</div><div>These results underscored the importance of ongoing monitoring for the management and conservation of coastal rocky habitats in the Southeastern Bay of Biscay. The findings highlight the capacity of this monitoring method to detect early signs of ecosystem change and reveal emerging stressors. The effect of the change and the transition to a new state on ecosystem functioning are discussed.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104171"},"PeriodicalIF":2.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840536","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":"Long-term changes in the deep chlorophyll maximum and primary production in the deep-water basin of the Black Sea","authors":"Sergey A. Mosharov ,&nbsp;Alexander S. Mikaelyan ,&nbsp;Alexandra V. Sergeeva ,&nbsp;Vladimir I. Gagarin","doi":"10.1016/j.jmarsys.2025.104169","DOIUrl":"10.1016/j.jmarsys.2025.104169","url":null,"abstract":"<div><div>Long-term changes in the deep chlorophyll maximum (DCM) and the depth-integrated primary production (PP) in the Black Sea deep basin from 1953 to 2021 were analysed. The changes were compared with alterations in water transparency, nitrate concentration in the deep maximum (NO₃-max), its depth and the intensity of winter convection affecting the nutrient supply in the upper layer through the year. A regression between the light attenuation coefficient and the Secchi disk depth was constructed based on field data obtained over the past two decades. The regression differed from that constructed using data before 1989. Both regressions were used to reconstruct long-term changes in the euphotic zone depth. Over 68 years, in the stratified period from April to October, it varied from 21 to 43 m. The annual mean DCM depth ranged from 18 to 55 m and was, in most cases, confined to a depth of 1–2 % of the surface photosynthetically available radiation. The long-term dynamics of annual means of DCM and PP DCM and PP generally corresponded to the change in NO₃-max. These variables were significantly correlated with NO₃-max, supporting the hypothesis that NO₃-max variations altered the nitrate gradient and, consequently, its upward flux into the photic zone, primarily consumed by DCM. At the same time, long-term changes in DCM and PP were also influenced by winter convection, affecting the nutrient supply in the upper layer and the macro-hydrodynamics of the Black Sea throughout the year. After a peak in eutrophication in the mid-1980s and a decline after the mid-1990s, NO₃-max began to rise again in the last decade, indicating a new increase in eutrophication. The increasing trends in NO₃-max and DCM and an increase in phytoplankton biomass, primarily due to diatoms, support this assumption.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104169"},"PeriodicalIF":2.5,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797909","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":"Southern Ocean salp diel vertical migration and the significant influence of life cycle stage and body size","authors":"Alexis A. Bahl ,&nbsp;Florian Lüskow ,&nbsp;Moira Décima ,&nbsp;Deborah K. Steinberg ,&nbsp;Evgeny A. Pakhomov","doi":"10.1016/j.jmarsys.2025.104161","DOIUrl":"10.1016/j.jmarsys.2025.104161","url":null,"abstract":"<div><div>Diel vertical migration (DVM) is a widespread behavior among zooplankton and micronekton, playing a crucial role in carbon cycling by transporting organic matter to depth. The Southern Ocean salp, <em>Salpa thompsoni</em>, is an abundant gelatinous zooplankton species recognized for its significant contribution to vertical carbon export. It’s high grazing capacity, production of rapidly sinking fecal pellets, and extensive DVMs make it a key player in biogeochemical cycles. Despite its ecological importance, the influence of the life cycle stage and body size on <em>S. thompsoni</em>’s migratory behavior has been understudied. Utilizing net data from six Southern Ocean locations collected between 1989 and 2018, we provide stage- and size-specific vertical distribution and migration distance estimates, supported by circumpolar predictions using a mixed-effects modeling approach. Our results reveal that small-bodied, early developmental salps migrate amplitudes up to three times greater than their larger, reproductive counterparts, which tend to remain stationary or undergo reverse DVM. Environmental factors, such as salinity and euphotic zone depth strongly influence <em>S. thompsoni</em> DVM patterns, with the potential to impose as primary controls on the main hypothesized driver, reproduction. This first Southern Ocean-wide analysis of <em>S. thompsoni</em> DVM underscores the critical importance of incorporating life cycle stage and body size into assessments of salp behavior. Understanding these dynamics is essential for improving the estimated vertical carbon export via the migrant pump and refining global biogeochemical models.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104161"},"PeriodicalIF":2.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797907","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":"Extreme underestimation of satellite-derived chlorophyll-a concentration in the northwestern Weddell Sea during a phytoplankton bloom and its reasons","authors":"Pavel A. Salyuk ,&nbsp;Dmitry I. Glukhovets ,&nbsp;Alexander A. Latushkin ,&nbsp;Olga Yu. Kalinina ,&nbsp;Elena A. Shtraikhert ,&nbsp;Philipp V. Sapozhnikov ,&nbsp;Sergey A. Mosharov ,&nbsp;Igor E. Stepochkin ,&nbsp;Nadezhda A. Lipinskaya ,&nbsp;Maxim I. Gorbov ,&nbsp;Svetlana K. Klimenko","doi":"10.1016/j.jmarsys.2025.104159","DOIUrl":"10.1016/j.jmarsys.2025.104159","url":null,"abstract":"<div><div>The data obtained from satellite and expedition measurements during the 87th cruise of the R/V Akademik Mstislav Keldysh revealed a significant discrepancy in chlorophyll-<em>a</em> (Chl-<em>a</em>) concentration estimates. Specifically, satellite-derived estimates were found to be underestimated by a factor of more than 25 in the region of an intense phytoplankton bloom in the northwestern part of the Weddell Sea near the Antarctic Peninsula in January 2022. This study aims to identify the reasons for the significant underestimation by satellite and above-water remote sensing data and to examine the related regional bio-optical features, phytoplankton community characteristics, and challenges in atmospheric correction.</div><div>The in situ Chl-<em>a</em> concentration measured by standard extraction methods (with pheophytin-a correction) was 7.9 mg m⁻³, whereas standard satellite bio-optical algorithms produced values of around 0.25 mg m⁻³, and above-water remote sensing provided values of about 1.6–2.0 mg m⁻³. The underestimation was observed in both Level 2 and more rigorously filtered Level 3 satellite ocean color data, suggesting that similar biases might affect other studies relying on satellite-derived Chl-<em>a</em> maps.</div><div>The extreme underestimation (approximately 25–100-fold) of satellite-derived Chl-<em>a</em> was caused mainly by errors in atmospheric correction. The identified bio-optical reasons leading to the remote underestimation of Chl-<em>a</em> concentration by a factor of approximately 4 are attributed to relatively low specific light absorption by phytoplankton cells, non-phytoplankton particles, and colored dissolved organic matter compared to global ocean averages. As a result, the depth of the photic zone was approximately twice that expected for the given Chl-<em>a</em> concentration. Additionally, the study demonstrates that spectral shape and low values of the above-water remote-sensing reflectance are significantly influenced by reduced particulate backscattering fraction and near-zero exponent in the power-law fit to the particulate beam attenuation spectrum. All observed regional bio-optical features were significantly influenced by pigment packaging and the prevalence of nano- and micro- phytoplankton cells, which predominantly formed large colonies (tens to hundreds of microns) and aggregates exceeding 100 μm.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"252 ","pages":"Article 104159"},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623988","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":"Physical and biogeochemical properties in Admiralty Bay and its connection with the Bransfield Strait, Antarctica, during the austral summers of 2019, 2022, and 2023","authors":"Maria E.A. Ishimaru ,&nbsp;Carlos Noriega ,&nbsp;Syumara Queiroz ,&nbsp;Marcus Silva ,&nbsp;Luís F. F. Mendonça ,&nbsp;Ana C.R. de Albergaria-Barbosa ,&nbsp;Basílio S. Neto ,&nbsp;Renato da Silva Carreira ,&nbsp;Pedro Melo ,&nbsp;Pedro M. Meirelles ,&nbsp;Gisele Olímpio da Rocha ,&nbsp;Jailson Bittencourt Andrade ,&nbsp;Cláudia V.S. Cavalcanti ,&nbsp;Moacyr Araújo","doi":"10.1016/j.jmarsys.2025.104162","DOIUrl":"10.1016/j.jmarsys.2025.104162","url":null,"abstract":"<div><div>We investigated spatial (inside/outside) and temporal (austral summers of 2019, 2022, and 2023) variability of physical and biogeochemical properties in Admiralty Bay (AB) using in-situ data from CTD and seawater samples complemented by 2022/2023 Global Ocean Physics Analysis and Forecast product. Temperature (−1.0 to 0.2 °C), salinity (34.1 to 34.5), oxygen (246 to 340 μmol kg⁻¹) presented significative differences between stations inside and outside the AB. Salinity was higher outside for all years, while temperature/oxygen was higher/lower (317.3 vs. 304 μmol kg⁻1) inside the bay in 2019 and outside the bay in 2022 and 2023. Transitional Zonal Water with Weddell Sea influence were dominant during all years, however in 2023, bottom waters outside AB exhibited modified Circumpolar Deep Water (mCDW). Higher oxygen apparent utilization (AOU) (52.6 vs. 40.0 μmol kg⁻¹) and nitrate plus nitrite (28.0 vs. 25.0 μmol kg⁻¹) was observed outside the AB, while phosphate was higher inside (1.6 vs. 1.2 μmol kg⁻¹), resulting in distinct N:P ratios of 24:1 and 17:1, respectively. Those patterns indicate reduced respiration and more efficient vertical ventilation inside and higher oxygen consumption and remineralization outside the AB. While surrounding shelf waters showed signs of climate-driven intrusions and interannual variability, the interior of AB did not display major hydrographic shifts during the study period. The absence of mCDW signature inside the bay may be a consequence of intense vertical mixing and local circulation patterns, that can alter/inhibit mCDW intrusions. Still, high-resolution monitoring and modeling are required to resolve the mechanisms that control exchange processes and detect emerging climate signals in this Antarctic coastal system.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"253 ","pages":"Article 104162"},"PeriodicalIF":2.5,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145658442","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}