Near-inertial and double-inertial internal waves (NIWs and DIWs) are frequently observed in the frontal region of the Sea of Japan during typhoon events. However, the mechanisms behind their generation, propagation, and dissipation, particularly under the influence of mesoscale structure of the Tsushima Warm Current (TWC), remain unclear. This study employs a numerical model with wind forcing from Typhoon Tapah (September 2019) to investigate these wave behaviors. Two experiments, one with the TWC (WITH-TWC) and one without it (NO-TWC), reveal striking contrasts. The TWC generates mesoscale features with negative relative vorticity, which effectively trap NIWs and prevent their escape. DIWs, in contrast, grow rapidly, radiate poleward, and dissipate within a few days. Modal dispersion theory explains how NIWs remain confined to mesoscale features, while DIWs and higher-frequency waves escape due to their higher group velocities. The DIW wave energy concentrates predominantly in the lowest vertical modes (typically, 1st–3rd), enabling efficient long-distance energy transfer with minimal distortion. A statistical analysis further indicates that regions of negative vorticity coincide with enhanced wave kinetic energy, especially for NIWs, supporting the interpretation that anticyclonic eddies act as effective traps and amplifiers of wave energy. These findings underscore the critical role of mesoscale eddies in regulating energy pathways of typhoon-induced internal waves, advancing general understanding of ocean mixing and energy redistribution in the Asian marginal seas.
{"title":"Meridional propagation of typhoon-generated internal waves under influences of mesoscale eddies in the Sea of Japan","authors":"Yusuke Kawaguchi , Itsuka Yabe , Taku Wagawa , Shigeyoshi Otosaka , Tomoharu Senjyu","doi":"10.1016/j.pocean.2025.103626","DOIUrl":"10.1016/j.pocean.2025.103626","url":null,"abstract":"<div><div>Near-inertial and double-inertial internal waves (NIWs and DIWs) are frequently observed in the frontal region of the Sea of Japan during typhoon events. However, the mechanisms behind their generation, propagation, and dissipation, particularly under the influence of mesoscale structure of the Tsushima Warm Current (TWC), remain unclear. This study employs a numerical model with wind forcing from Typhoon <em>Tapah</em> (September 2019) to investigate these wave behaviors. Two experiments, one with the TWC (WITH-TWC) and one without it (NO-TWC), reveal striking contrasts. The TWC generates mesoscale features with negative relative vorticity, which effectively trap NIWs and prevent their escape. DIWs, in contrast, grow rapidly, radiate poleward, and dissipate within a few days. Modal dispersion theory explains how NIWs remain confined to mesoscale features, while DIWs and higher-frequency waves escape due to their higher group velocities. The DIW wave energy concentrates predominantly in the lowest vertical modes (typically, 1st–3rd), enabling efficient long-distance energy transfer with minimal distortion. A statistical analysis further indicates that regions of negative vorticity coincide with enhanced wave kinetic energy, especially for NIWs, supporting the interpretation that anticyclonic eddies act as effective traps and amplifiers of wave energy. These findings underscore the critical role of mesoscale eddies in regulating energy pathways of typhoon-induced internal waves, advancing general understanding of ocean mixing and energy redistribution in the Asian marginal seas.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103626"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145583883","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 : 2026-01-01Epub Date: 2025-12-24DOI: 10.1016/j.pocean.2025.103661
Danushka Deegala, Eun-Sung Chung
This study investigated the marine heatwaves (MHWs) in the Arabian Sea (AS) and Bay of Bengal (BoB) during pre-monsoon (March-April-May, MAM), monsoon (June-July-August-September, JJAS), and post-monsoon (October-November-December, OND) seasons using observations from NOAA and the simulations from 17 CMIP6 Global Climate Models (GCMs) under four Shared Socioeconomic Pathways (SSPs). MHW metrics of frequency, maximum intensity, and duration were analyzed for the historical period (1985–2014) and for the near (2031–2060, NF) and far (2061–2090, FF) future periods. Two approaches, fixed-baseline and shifted-baseline, were applied for the future projection of MHWs. Observed NOAA values indicated higher trends in AS compared to BoB for all MHW metrics during all seasons. Future projections under the fixed-baseline approach indicated model agreement on positive shifts ranging from 43 % to 136 % for frequency, 89 % to 173 % for maximum intensity, and 545 % to 1225 % for duration in the NF compared to the historical, with BoB showing higher positive changes than AS during JJAS and OND under all SSPs. The fixed-baseline approach suggested MHWs attaining a permanent state towards the FF. Model agreement on future trends under the shifted-baseline indicated higher trend values in the NF compared to historical from SSP2-4.5 to SSP5-8.5 across all MHW metrics during all seasons, while the FF indicated higher trends from SSP3-7.0 to SSP5-8.5. Additionally, under the shifted-baseline, FF exhibited higher trend values than NF. Model agreement under the fixed-baseline approach indicated more vulnerability in the northwestern regions of AS to an increase of MHW frequency during MAM and JJAS in the NF.
{"title":"Future seasonal changes of marine heatwaves in the Arabian Sea and Bay of Bengal","authors":"Danushka Deegala, Eun-Sung Chung","doi":"10.1016/j.pocean.2025.103661","DOIUrl":"10.1016/j.pocean.2025.103661","url":null,"abstract":"<div><div>This study investigated the marine heatwaves (MHWs) in the Arabian Sea (AS) and Bay of Bengal (BoB) during pre-monsoon (March-April-May, MAM), monsoon (June-July-August-September, JJAS), and post-monsoon (October-November-December, OND) seasons using observations from NOAA and the simulations from 17 CMIP6 Global Climate Models (GCMs) under four Shared Socioeconomic Pathways (SSPs). MHW metrics of frequency, maximum intensity, and duration were analyzed for the historical period (1985–2014) and for the near (2031–2060, NF) and far (2061–2090, FF) future periods. Two approaches, fixed-baseline and shifted-baseline, were applied for the future projection of MHWs. Observed NOAA values indicated higher trends in AS compared to BoB for all MHW metrics during all seasons. Future projections under the fixed-baseline approach indicated model agreement on positive shifts ranging from 43<!--> <!-->% to 136<!--> <!-->% for frequency, 89<!--> <!-->% to 173<!--> <!-->% for maximum intensity, and 545<!--> <!-->% to 1225<!--> <!-->% for duration in the NF compared to the historical, with BoB showing higher positive changes than AS during JJAS and OND under all SSPs. The fixed-baseline approach suggested MHWs attaining a permanent state towards the FF. Model agreement on future trends under the shifted-baseline indicated higher trend values in the NF compared to historical from SSP2-4.5 to SSP5-8.5 across all MHW metrics during all seasons, while the FF indicated higher trends from SSP3-7.0 to SSP5-8.5. Additionally, under the shifted-baseline, FF exhibited higher trend values than NF. Model agreement under the fixed-baseline approach indicated more vulnerability in the northwestern regions of AS to an increase of MHW frequency during MAM and JJAS in the NF.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103661"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145823462","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}
The AleutBio Expedition, which was conducted from July to September 2022 across the Aleutian Trench and abyssal depths of the Bering Sea, aimed at expanding the knowledge on the distribution of marine organisms in the subpolar northern Pacific Ocean. The present study analyses ostracods (Crustacea) collected during this expedition and presents the descriptions of three new, deep-sea ostracod species from the family Trachyleberididae: Abyssocythere piovesanae sp. nov., Abyssocythereis matzkekaraszae sp. nov., and Henryhowella coronispinata sp. nov. The material was collected using two types of epibenthic sledges from 10 stations at depths from 3,500 to 7,200 m. Morphological analysis was conducted via stereomicroscopy of the soft body and scanning electron microscopy of the valves. It is the first time that soft parts of Abyssocythere and Henryhowella are described. Our findings expand the known geographic distribution of these genera and offer insights into their morphological diversity, including unique ornamentation patterns, hinge structures and valve overlap. We also provide a new synonymy for the two previously described species of Abyssocythereis and a review of Abyssocythereis sulcatoperforata (Brady, 1880), based on the reanalysis of its lectotype and, we also describe the soft parts of Henryhowella for the first time. Our research contributes significantly to the understanding of ostracod diversity and adaptation in the deep sea and underlines the importance of continued exploration of these largely understudied ecosystems.
{"title":"Biogeographic range expansion of Trachyleberididae (Ostracoda, Crustacea) genera evidenced by three new species from the Aleutian Trench and Bering Sea","authors":"Rayran Araújo Praxedes , Angelika Brandt , Simone Nunes Brandão","doi":"10.1016/j.pocean.2025.103617","DOIUrl":"10.1016/j.pocean.2025.103617","url":null,"abstract":"<div><div>The AleutBio Expedition, which was conducted from July to September 2022 across the Aleutian Trench and abyssal depths of the Bering Sea, aimed at expanding the knowledge on the distribution of marine organisms in the subpolar northern Pacific Ocean. The present study analyses ostracods (Crustacea) collected during this expedition and presents the descriptions of three new, deep-sea ostracod species from the family Trachyleberididae: <em>Abyssocythere piovesanae</em> sp. nov., <em>Abyssocythereis matzkekaraszae</em> sp. nov., and <em>Henryhowella coronispinata</em> sp. nov. The material was collected using two types of epibenthic sledges from 10 stations at depths from 3,500 to 7,200 m. Morphological analysis was conducted via stereomicroscopy of the soft body and scanning electron microscopy of the valves. It is the first time that soft parts of <em>Abyssocythere</em> and <em>Henryhowella</em> are described. Our findings expand the known geographic distribution of these genera and offer insights into their morphological diversity, including unique ornamentation patterns, hinge structures and valve overlap. We also provide a new synonymy for the two previously described species of <em>Abyssocythereis</em> and a review of <em>Abyssocythereis sulcatoperforata</em> (<span><span>Brady, 1880</span></span>), based on the reanalysis of its lectotype and, we also describe the soft parts of <em>Henryhowella</em> for the first time. Our research contributes significantly to the understanding of ostracod diversity and adaptation in the deep sea and underlines the importance of continued exploration of these largely understudied ecosystems.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"240 ","pages":"Article 103617"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145531173","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 : 2026-01-01Epub Date: 2025-11-20DOI: 10.1016/j.pocean.2025.103625
Zeshu Yu , Marty Kwok-Shing Wong , Jun Inoue , Yuan Lin , Itsuka Yabe , Tomihiko Higuchi , Susumu Hyodo , Sachihiko Itoh , Yuichiro Nishibe , Hajime Obata , Shin-ichi Ito
Environmental DNA (eDNA) method has been widely used worldwide for ecological surveys of fish. However, the accuracy of eDNA in deducing fish distribution, especially vertical distribution in the open ocean, is uncertain due to insufficient observation. This paper observed and studied the eDNA vertical distribution in the open ocean, focusing on two economically important small pelagic fishes, Sardinops melanostictus and Engraulis japonicus (here after sardine and anchovy respectively) in the Northwest Pacific. From the uninhabitable deep ocean layers, their eDNA was detected and we referred them as “DP-eDNA”, which suggests eDNA from pelagic fish may exist far below where they live. Higher DP-eDNA ratios were observed for sardine and anchovy when seawater temperature was lower, likely due to slower degradation. The sardine DP-eDNA ratio was higher when chlorophyll-a concentration (and turbidity) was higher, which may suggest that the fish eDNA could be attached to phytoplankton-produced particles that enhanced the eDNA sinking. Meanwhile, for anchovy, the DP-eDNA ratio was lower when dissolved oxygen concentrations were higher, which may be caused by a faster microbial-related degradation. The eDNA sinking velocity was estimated to be 39 − 255 m day−1 (sardine) and 36 − 241 m day−1 (anchovy), values comparable to the observation data in particulate organic matter (POM), although the DP-eDNA formation mechanism could be more complex than simple sinking. This study recorded the downward vertical movement of DNA in open ocean and its environmental-dependent characteristics, and our results deepen the considerations that should be taken when eDNA is used to deduce the vertical distribution of fish in the open ocean.
环境DNA （Environmental DNA, eDNA）方法在鱼类生态调查中得到了广泛的应用。然而，由于观测不足，eDNA推断鱼类分布的准确性，特别是在公海的垂直分布，是不确定的。本文以西北太平洋两种具有重要经济意义的小型中上层鱼类——沙丁鱼（Sardinops melanotictus）和日本沙丁鱼（Engraulis japonicus）为研究对象，对其在公海的垂直分布进行了观察和研究。从不适合居住的深海层中，检测到它们的eDNA，我们将它们称为“DP-eDNA”，这表明来自远洋鱼类的eDNA可能存在于它们生活的远低于它们的地方。当海水温度较低时，沙丁鱼和凤尾鱼的DP-eDNA比值较高，可能是由于降解速度较慢。当叶绿素-a浓度（和浑浊度）越高时，沙丁鱼的DP-eDNA比值越高，这可能表明鱼的eDNA可能附着在浮游植物产生的颗粒上，从而增强了eDNA的下沉。同时，对于凤尾鱼来说，溶解氧浓度越高，DP-eDNA比值越低，这可能是由于微生物相关的降解速度越快。eDNA沉降速度估计为39 ~ 255 m day−1（沙丁鱼）和36 ~ 241 m day−1（凤尾鱼），与颗粒有机质（POM）的观测数据相当，尽管DP-eDNA的形成机制可能比简单的沉降更为复杂。本研究记录了开放海洋中DNA的垂直向下运动及其环境依赖特征，我们的研究结果加深了使用eDNA推断开放海洋中鱼类垂直分布时应考虑的问题。
{"title":"Environmental DNA of small pelagic fish in the deep ocean","authors":"Zeshu Yu , Marty Kwok-Shing Wong , Jun Inoue , Yuan Lin , Itsuka Yabe , Tomihiko Higuchi , Susumu Hyodo , Sachihiko Itoh , Yuichiro Nishibe , Hajime Obata , Shin-ichi Ito","doi":"10.1016/j.pocean.2025.103625","DOIUrl":"10.1016/j.pocean.2025.103625","url":null,"abstract":"<div><div>Environmental DNA (eDNA) method has been widely used worldwide for ecological surveys of fish. However, the accuracy of eDNA in deducing fish distribution, especially vertical distribution in the open ocean, is uncertain due to insufficient observation. This paper observed and studied the eDNA vertical distribution in the open ocean, focusing on two economically important small pelagic fishes, <em>Sardinops melanostictus</em> and <em>Engraulis japonicus</em> (here after sardine and anchovy respectively) in the Northwest Pacific. From the uninhabitable deep ocean layers, their eDNA was detected and we referred them as “DP-eDNA”, which suggests eDNA from pelagic fish may exist far below where they live. Higher DP-eDNA ratios were observed for sardine and anchovy when seawater temperature was lower, likely due to slower degradation. The sardine DP-eDNA ratio was higher when chlorophyll-a concentration (and turbidity) was higher, which may suggest that the fish eDNA could be attached to phytoplankton-produced particles that enhanced the eDNA sinking. Meanwhile, for anchovy, the DP-eDNA ratio was lower when dissolved oxygen concentrations were higher, which may be caused by a faster microbial-related degradation. The eDNA sinking velocity was estimated to be 39 − 255 m day<sup>−1</sup> (sardine) and 36 − 241 m day<sup>−1</sup> (anchovy), values comparable to the observation data in particulate organic matter (POM), although the DP-eDNA formation mechanism could be more complex than simple sinking. This study recorded the downward vertical movement of DNA in open ocean and its environmental-dependent characteristics, and our results deepen the considerations that should be taken when eDNA is used to deduce the vertical distribution of fish in the open ocean.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103625"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145559765","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 : 2026-01-01Epub Date: 2025-10-10DOI: 10.1016/j.pocean.2025.103586
Marta Gellert , Magdalena Błażewicz , Graham J. Bird
The deep-sea paratanaoidean family Typhlotanaidae remains understudied, both taxonomically and phylogenetically, particularly in the North Pacific. This study examines previously undocumented representatives of the genus Typhlamia collected from the Aleutian region. Using an integrative approach that combines morphological analysis and, in one case, molecular data based on 18S rDNA sequences, we identify distinct lineages within the genus. The genetic data reveal a well-supported clade that is clearly separated from the other sequenced members of Typhlamia, suggesting the genus may be polyphyletic and in need of revision. Morphological characteristics further support the distinctiveness of the examined specimens. Their occurrence on either slope of the Aleutian Trench indicate that this region may act as a partial biogeographic barrier, while also hosting previously undocumented deep-sea diversity. These findings highlight the Aleutian region as an important area for understanding the evolution, dispersal, and hidden biodiversity of deep-sea peracarids.
{"title":"New light in the North Pacific: Two new species of Typhlotanaidae (Crustacea: Tanaidacea) from the Aleutian region","authors":"Marta Gellert , Magdalena Błażewicz , Graham J. Bird","doi":"10.1016/j.pocean.2025.103586","DOIUrl":"10.1016/j.pocean.2025.103586","url":null,"abstract":"<div><div>The deep-sea paratanaoidean family Typhlotanaidae remains understudied, both taxonomically and phylogenetically, particularly in the North Pacific. This study examines previously undocumented representatives of the genus <em>Typhlamia</em> collected from the Aleutian region. Using an integrative approach that combines morphological analysis and, in one case, molecular data based on 18S rDNA sequences, we identify distinct lineages within the genus. The genetic data reveal a well-supported clade that is clearly separated from the other sequenced members of <em>Typhlamia</em>, suggesting the genus may be polyphyletic and in need of revision. Morphological characteristics further support the distinctiveness of the examined specimens. Their occurrence on either slope of the Aleutian Trench indicate that this region may act as a partial biogeographic barrier, while also hosting previously undocumented deep-sea diversity. These findings highlight the Aleutian region as an important area for understanding the evolution, dispersal, and hidden biodiversity of deep-sea peracarids.</div><div>LSIDurn:lsid:zoobank.org:pub:8574DCBD-8E4A-40BC-914A-473DC69A4634.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103586"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145610390","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}
Internal solitary waves (ISWs) are commonly emitted in stratified flows under the action of the tidal current over rough topography. ISWs have been extensively observed far from their generation zone. However, there is a scarcity of in-situ measurements where these phenomena originate, and our comprehension of their generation heavily relies on numerical simulations. The Strait of Gibraltar is well known for large amplitude ISWs propagating eastward from Camarinal Sill – the main topographic feature – towards the Alboran Sea. Our field experiment and satellite images reveal the complex spatial structure of the bore at the Camarinal Sill, showing multiple bores. We evidence that two packets of organized ISWs effectively propagate near the generation zone, leading to different signatures at our moorings. This analysis offers a unique chance to compare synchronous in-situ data with satellite images of internal bore. Finally, the possible consequences of these multiple wave trains in the far field dynamics are discussed with a focus on the non-rank-ordered pattern observed at the eastern exit of the Strait.
{"title":"Variability of the internal solitary waves generated at Camarinal Sill in the Strait of Gibraltar","authors":"Jean-Baptiste Roustan , Lucie Bordois , Xavier Carton , Francis Auclair , Franck Dumas","doi":"10.1016/j.pocean.2025.103621","DOIUrl":"10.1016/j.pocean.2025.103621","url":null,"abstract":"<div><div>Internal solitary waves (ISWs) are commonly emitted in stratified flows under the action of the tidal current over rough topography. ISWs have been extensively observed far from their generation zone. However, there is a scarcity of in-situ measurements where these phenomena originate, and our comprehension of their generation heavily relies on numerical simulations. The Strait of Gibraltar is well known for large amplitude ISWs propagating eastward from Camarinal Sill – the main topographic feature – towards the Alboran Sea. Our field experiment and satellite images reveal the complex spatial structure of the bore at the Camarinal Sill, showing multiple bores. We evidence that two packets of organized ISWs effectively propagate near the generation zone, leading to different signatures at our moorings. This analysis offers a unique chance to compare synchronous in-situ data with satellite images of internal bore. Finally, the possible consequences of these multiple wave trains in the far field dynamics are discussed with a focus on the non-rank-ordered pattern observed at the eastern exit of the Strait.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103621"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145553663","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 : 2026-01-01Epub Date: 2025-11-18DOI: 10.1016/j.pocean.2025.103624
E. Trudnowska , P. Balazy , M. Bagur , P. Kuklinski , J. Kaminsky , K. Balazy , M. Rodriguez , Z. Derwich , G. Lovrich
The waters of the Beagle Channel (55ºS; 66–70ºW) are supplied by the Cape Horn Current and become progressively modified as they flow eastward. We followed dynamics of particles and suspension feeders within Macrocystis pyrifera kelp forests along this passage spanning from the gradient starting at the inner, glacier-influenced area to the outermost oceanic region. This was realized by the simultaneous, short-term (4-days per location) but high temporal-resolution (minutes) measurements of physical environment, particle pools, and barnacle activity. An array of loggers to measure light, salinity, temperature, pH, oxygen, water level, and currents along with sediment traps, and two underwater cameras that recorded suspended particles and benthic activity were set to discuss the effect of kelp forests on modifying their coupling along the studied gradient. This included suppression of water flow and resulting entrapment of particles in dense forests, which subsequently led to high concentrations of accumulated material to be resuspended. The lower exchange of waters in a sheltered location resulted in stronger local impact of kelps on changing biochemistry of waters (e.g., increased pH through their photosynthesis). Study site with low density of kelps at glacier-influenced site enabled better light penetration in contrast to dense oceanic forests, which was of importance for barnacles displaying diurnal cyclicity in their feeding, with higher activity during night hours at two inner locations. Tidal cycles were also important for barnacles feeding, but the relation was time-lagged. The morphology of detritus reflected different origin of material (mineral vs. organic) along the studied horizontal gradient, but also different sources of particles (local vs. advected), governed by horizontal import/export via currents and tidal dynamics. Abrupt weather episodes, diurnal and tidal cycles were the main sources of bulk observed variability which illustrates how local processes, combined with episodic environmental variations interact to drive coastal benthic dynamics in a symphony characterized by distinct rhythms. Consequently, we highlight the importance of high-resolution observations to get better understanding of the functioning of kelp forests’ associated fauna and suspended matter, and that incorporating all sources of impactful variability, including atmospheric forcing, is required.
{"title":"The rhythms of environmental conditions, particles dynamics, and barnacle activity captured by underwater imaging in sub-Antarctic kelp forests of the Beagle Channel","authors":"E. Trudnowska , P. Balazy , M. Bagur , P. Kuklinski , J. Kaminsky , K. Balazy , M. Rodriguez , Z. Derwich , G. Lovrich","doi":"10.1016/j.pocean.2025.103624","DOIUrl":"10.1016/j.pocean.2025.103624","url":null,"abstract":"<div><div>The waters of the Beagle Channel (55ºS; 66–70ºW) are supplied by the Cape Horn Current and become progressively modified as they flow eastward. We followed dynamics of particles and suspension feeders within <em>Macrocystis pyrifera</em> kelp forests along this passage spanning from the gradient starting at the inner, glacier-influenced area to the outermost oceanic region. This was realized by the simultaneous, short-term (4-days per location) but high temporal-resolution (minutes) measurements of physical environment, particle pools, and barnacle activity. An array of loggers to measure light, salinity, temperature, pH, oxygen, water level, and currents along with sediment traps, and two underwater cameras that recorded suspended particles and benthic activity were set to discuss the effect of kelp forests on modifying their coupling along the studied gradient. This included suppression of water flow and resulting entrapment of particles in dense forests, which subsequently led to high concentrations of accumulated material to be resuspended. The lower exchange of waters in a sheltered location resulted in stronger local impact of kelps on changing biochemistry of waters (e.g., increased pH through their photosynthesis). Study site with low density of kelps at glacier-influenced site enabled better light penetration in contrast to dense oceanic forests, which was of importance for barnacles displaying diurnal cyclicity in their feeding, with higher activity during night hours at two inner locations. Tidal cycles were also important for barnacles feeding, but the relation was time-lagged. The morphology of detritus reflected different origin of material (mineral vs. organic) along the studied horizontal gradient, but also different sources of particles (local vs. advected), governed by horizontal import/export via currents and tidal dynamics. Abrupt weather episodes, diurnal and tidal cycles were the main sources of bulk observed variability which illustrates how local processes, combined with episodic environmental variations interact to drive coastal benthic dynamics in a symphony characterized by distinct rhythms. Consequently, we highlight the importance of high-resolution observations to get better understanding of the functioning of kelp forests’ associated fauna and suspended matter, and that incorporating all sources of impactful variability, including atmospheric forcing, is required.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"240 ","pages":"Article 103624"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145553664","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 : 2026-01-01Epub Date: 2025-12-09DOI: 10.1016/j.pocean.2025.103645
Caixia Dong , Xiaotong Xiao , Li Li , Hailong Zhang , Meixun Zhao
Anammox is a major participant in the removal of inorganic nitrogen in marine ecosystems, especially in oxygen-deficient environments. In coastal areas, the distribution and response of anammox activity to long-term eutrophication and hypoxia have not been well documented. Here, three different ladderane fatty acids, utilized as anammox biomarkers, were measured in surface sediments from the Pearl River Estuary (PRE)-continental shelf of the South China Sea (SCS). The positive correlation (r = 0.76, p < 0.0001) between ladderane fatty acids contents (∑(Ⅱ+Ⅲ+Ⅳ)) and phytoplankton biomarkers contents (∑PB) indicated that eutrophication stimulated anammox activities. The ratio of C20-[5] to C20-[3]-ladderane fatty acids (Rlad) decreased from the coast towards the offshore, implying an anammox bacteria community shift from Candidatus (Ca.) Brocadia/Kuenenia to Ca. Scalindua in response to decreasing terrestrial input from the brackish environment to the marine environment. The negative correlations of bottom dissolved oxygen (DO) with ∑(Ⅱ+Ⅲ+Ⅳ) and Rlad indicated that ladderane fatty acids were potential bioindicators of hypoxia in the PRE. Our results revealed that the riverine input from the Pearl River may have caused eutrophication in the PRE and its adjacent continental shelf, which consequently influenced anammox activities. This study provided that ladderane fatty acids can be used to reconstruct past hypoxia and marine environment records beyond equipment observation in the continental marginal seas.
{"title":"Ladderanes in sediments indicating anammox activities from the Pearl River Estuary-continental shelf of the South China Sea","authors":"Caixia Dong , Xiaotong Xiao , Li Li , Hailong Zhang , Meixun Zhao","doi":"10.1016/j.pocean.2025.103645","DOIUrl":"10.1016/j.pocean.2025.103645","url":null,"abstract":"<div><div>Anammox is a major participant in the removal of inorganic nitrogen in marine ecosystems, especially in oxygen-deficient environments. In coastal areas, the distribution and response of anammox activity to long-term eutrophication and hypoxia have not been well documented. Here, three different ladderane fatty acids, utilized as anammox biomarkers, were measured in surface sediments from the Pearl River Estuary (PRE)-continental shelf of the South China Sea (SCS). The positive correlation (r = 0.76, p < 0.0001) between ladderane fatty acids contents (∑(Ⅱ+Ⅲ+Ⅳ)) and phytoplankton biomarkers contents (∑PB) indicated that eutrophication stimulated anammox activities. The ratio of C<sub>20</sub>-[5] to C<sub>20</sub>-[3]-ladderane fatty acids (R<sub>lad</sub>) decreased from the coast towards the offshore, implying an anammox bacteria community shift from <em>Candidatus</em> (<em>Ca.</em>) Brocadia/Kuenenia to <em>Ca.</em> Scalindua in response to decreasing terrestrial input from the brackish environment to the marine environment. The negative correlations of bottom dissolved oxygen (DO) with ∑(Ⅱ+Ⅲ+Ⅳ) and R<sub>lad</sub> indicated that ladderane fatty acids were potential bioindicators of hypoxia in the PRE. Our results revealed that the riverine input from the Pearl River may have caused eutrophication in the PRE and its adjacent continental shelf, which consequently influenced anammox activities. This study provided that ladderane fatty acids can be used to reconstruct past hypoxia and marine environment records beyond equipment observation in the continental marginal seas.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103645"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145731523","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 : 2026-01-01Epub Date: 2025-12-22DOI: 10.1016/j.pocean.2025.103659
Dezhi Bu , Xianghui Guo , Weidong Zhai , Yi Xu , Minhan Dai
Air-sea CO2 flux in marginal sea is an important component of the global ocean carbon cycle. Located between the East China Sea and the northern South China Sea shelves which are both CO2 sinks, the southeastern coast of Mainland China has large potential of CO2 sequestration, but studies on air-sea CO2 fluxes in this region are very limited. Surface water CO2 partial pressure (pCO2) and auxiliary parameters from 51 cruises conducted in 2001–2022 were integrated to estimate the air-sea CO2 fluxes. Surface water pCO2 exhibited conspicuous spatial and temporal variabilities. The lowest pCO2 occurred in winter (349 ± 20 μatm), gradually increased in spring (357 ± 21 μatm) and summer (371 ± 35 μatm), and reached a peak in fall (392 ± 27 μatm). Surface water pCO2 was primarily modulated by vertical mixing and cooling during cold seasons, and by coastal upwelling and biological CO2 uptake in warm seasons. Vertical water mixing and temperature effect induced highest pCO2 in fall. Air-sea CO2 fluxes also exhibited strong seasonal variations. The study area acts as a moderate to strong CO2 sinks of 9.4 ± 5.5 and 3.7 ± 3.9 mmol m−2 d-1 in winter and spring, respectively, and a CO2 source of 3.8 ± 7.0 mmol m−2 d-1 in fall. In summer, the surface water CO2 is near equilibrium with the atmosphere with an air-sea CO2 flux of −0.6 ± 2.8 mmol m−2 d-1. The annual average air-sea CO2 fluxes is −2.6 ± 6.8 mmol m−2 d-1, indicating the study area acting as a weak to moderate sink annually. pCO2 difference between the surface water and the atmosphere is the main factor regulating the seasonal variations of air-sea CO2 flux, and wind speed also played an important role, enhancing CO2 sink in winter.
{"title":"Surface water pCO2 and air-sea fluxes in the southeastern coast of Mainland China: Synthesis of a 22-year dataset of field observation","authors":"Dezhi Bu , Xianghui Guo , Weidong Zhai , Yi Xu , Minhan Dai","doi":"10.1016/j.pocean.2025.103659","DOIUrl":"10.1016/j.pocean.2025.103659","url":null,"abstract":"<div><div>Air-sea CO<sub>2</sub> flux in marginal sea is an important component of the global ocean carbon cycle. Located between the East China Sea and the northern South China Sea shelves which are both CO<sub>2</sub> sinks, the southeastern coast of Mainland China has large potential of CO<sub>2</sub> sequestration, but studies on air-sea CO<sub>2</sub> fluxes in this region are very limited. Surface water CO<sub>2</sub> partial pressure (<em>p</em>CO<sub>2</sub>) and auxiliary parameters from 51 cruises conducted in 2001–2022 were integrated to estimate the air-sea CO<sub>2</sub> fluxes. Surface water <em>p</em>CO<sub>2</sub> exhibited conspicuous spatial and temporal variabilities. The lowest <em>p</em>CO<sub>2</sub> occurred in winter (349 ± 20 μatm), gradually increased in spring (357 ± 21 μatm) and summer (371 ± 35 μatm), and reached a peak in fall (392 ± 27 μatm). Surface water <em>p</em>CO<sub>2</sub> was primarily modulated by vertical mixing and cooling during cold seasons, and by coastal upwelling and biological CO<sub>2</sub> uptake in warm seasons. Vertical water mixing and temperature effect induced highest <em>p</em>CO<sub>2</sub> in fall. Air-sea CO<sub>2</sub> fluxes also exhibited strong seasonal variations. The study area acts as a moderate to strong CO<sub>2</sub> sinks of 9.4 ± 5.5 and 3.7 ± 3.9 mmol m<sup>−2</sup> d<sup>-1</sup> in winter and spring, respectively, and a CO<sub>2</sub> source of 3.8 ± 7.0 mmol m<sup>−2</sup> d<sup>-1</sup> in fall. In summer, the surface water CO<sub>2</sub> is near equilibrium with the atmosphere with an air-sea CO<sub>2</sub> flux of −0.6 ± 2.8 mmol m<sup>−2</sup> d<sup>-1</sup>. The annual average air-sea CO<sub>2</sub> fluxes is −2.6 ± 6.8 mmol m<sup>−2</sup> d<sup>-1</sup>, indicating the study area acting as a weak to moderate sink annually. <em>p</em>CO<sub>2</sub> difference between the surface water and the atmosphere is the main factor regulating the seasonal variations of air-sea CO<sub>2</sub> flux, and wind speed also played an important role, enhancing CO<sub>2</sub> sink in winter.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103659"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145813737","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 : 2026-01-01Epub Date: 2025-12-05DOI: 10.1016/j.pocean.2025.103643
Candace J. Grimes , Anthony M. Bonacolta , Kenneth M. Halanych
The Aleutian Trench represents a high latitude, hadal environment where little is known about factors structuring host-microbiome interactions. Here, metagenomic data from annelid hosts were collected across abyssal (∼4,000––6,000 m) and hadal (>6,000 m) depths to assess how microbial community composition and function relates to feeding strategy and environmental conditions. Microbial assemblages varied among annelids, with feeding guild and host family emerging as the strongest predictor of community structure suggesting host ecology may play a substantial role in shaping microbial community structure and metabolic potential. Although depth alone was not a strong predictor of community composition, hadal samples exhibited enrichment in pathways associated with secondary metabolism and ion transport, consistent with adaptation to high pressure and low nutrient availability. Dominant taxa included Gammaproteobacteria, Alphaproteobacteria, Actinomycetes, and Methanomicrobia. Environmental gradients, particularly primary productivity, oxygen, and nitrate, were associated with distinct microbial profiles across stations which indicate local habitat conditions also contribute to variability in composition and function. These findings support the view that deep-sea microbiomes are structured by primarily host-associated factors that may be modulated by environmental factors. This study adds to growing evidence that functional variation in microbiomes reflect host traits and environmental context in deep-sea ecosystems.
{"title":"Microbial community composition and functional potential in Annelida from abyssal and hadal zones of the Aleutian trench","authors":"Candace J. Grimes , Anthony M. Bonacolta , Kenneth M. Halanych","doi":"10.1016/j.pocean.2025.103643","DOIUrl":"10.1016/j.pocean.2025.103643","url":null,"abstract":"<div><div>The Aleutian Trench represents a high latitude, hadal environment where little is known about factors structuring host-microbiome interactions. Here, metagenomic data from annelid hosts were collected across abyssal (∼4,000––6,000 m) and hadal (>6,000 m) depths to assess how microbial community composition and function relates to feeding strategy and environmental conditions. Microbial assemblages varied among annelids, with feeding guild and host family emerging as the strongest predictor of community structure suggesting host ecology may play a substantial role in shaping microbial community structure and metabolic potential. Although depth alone was not a strong predictor of community composition, hadal samples exhibited enrichment in pathways associated with secondary metabolism and ion transport, consistent with adaptation to high pressure and low nutrient availability. Dominant taxa included <em>Gammaproteobacteria</em>, <em>Alphaproteobacteria</em>, <em>Actinomycetes</em>, and <em>Methanomicrobia</em>. Environmental gradients, particularly primary productivity, oxygen, and nitrate, were associated with distinct microbial profiles across stations which indicate local habitat conditions also contribute to variability in composition and function. These findings support the view that deep-sea microbiomes are structured by primarily host-associated factors that may be modulated by environmental factors. This study adds to growing evidence that functional variation in microbiomes reflect host traits and environmental context in deep-sea ecosystems.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103643"},"PeriodicalIF":3.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689918","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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