Pub Date : 2026-01-23DOI: 10.1016/j.pocean.2026.103683
Derya Akdogan, Angelika Brandt, Stefanie Kaiser
{"title":"A new species of Austroniscus Vanhöffen, 1914 (Isopoda, Asellota, Nannoniscidae Hansen, 1914) from abyssal depths of the Aleutian Trench, north-eastern Pacific","authors":"Derya Akdogan, Angelika Brandt, Stefanie Kaiser","doi":"10.1016/j.pocean.2026.103683","DOIUrl":"https://doi.org/10.1016/j.pocean.2026.103683","url":null,"abstract":"","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"46 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033593","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 : 2026-01-19DOI: 10.1016/j.pocean.2026.103682
Andreas Kelch, Laura Spies, Davide Di Franco, Maria A. Nilsson, Sven Rossel, Pedro Martinez Arbizu, Anja Rauh, Heiko Stuckas, Stefanie Kaiser, Angelika Brandt
{"title":"Integrative taxonomy of mesosignidae Schultz, 1969 (Crustacea, Malacostraca) from North Pacific trenches: new species description and biogeographic insights from morphology, mtDNA, and proteomics","authors":"Andreas Kelch, Laura Spies, Davide Di Franco, Maria A. Nilsson, Sven Rossel, Pedro Martinez Arbizu, Anja Rauh, Heiko Stuckas, Stefanie Kaiser, Angelika Brandt","doi":"10.1016/j.pocean.2026.103682","DOIUrl":"https://doi.org/10.1016/j.pocean.2026.103682","url":null,"abstract":"","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"123 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146001427","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 : 2026-01-16DOI: 10.1016/j.pocean.2026.103679
Rodrigo Mogollón , Dante Espinoza-Morriberón , Oswaldo Velasquez , Guisela Yabar , Manuel Villena , Jorge Tam
The 2017 Marine Heatwave event was characterized by significant positive sea surface temperature anomalies driven by weakened and reversed wind patterns, from mid-January to mid-April. The wind reversal during the Coastal El Niño favored downwelling processes, limiting the upward transport of nutrient-rich waters and causing a rapid collapse in surface phytoplankton biomass. Additionally, reduced latent heat flux and increased shortwave radiation further exacerbated surface warming. From February to March 2017, chlorophyll-a concentrations showed strong negative anomalies (more than −3 mg m−3), with the High Productive Zone (HPZ) contracting significantly, from 300 km offshore in January to nearly 25 km from the coast during this two-months period, while the total HPZ area decreased by up to 130,000 km2 in March, demonstrating a sharp decline in surface chlorophyll-a concentration. However, as physical drivers tend to return to typical seasonal values by April, upwelling resumed, positive chlorophyll-a anomalies emerged indicating a relatively rapid recovery of phytoplankton biomass, and the HPZ re-expanded toward climatological levels. These findings emphasize the sensitivity of the northern Peruvian marine ecosystem to short-term climate variability. Given the increasing frequency of these climatic events, understanding the physical drivers of ecosystem changes is critical for predicting future impacts and informing adaptive management strategies.
{"title":"Chlorophyll response and High Productivity Zone contraction in northern Perú during the 2017 Coastal El Niño","authors":"Rodrigo Mogollón , Dante Espinoza-Morriberón , Oswaldo Velasquez , Guisela Yabar , Manuel Villena , Jorge Tam","doi":"10.1016/j.pocean.2026.103679","DOIUrl":"10.1016/j.pocean.2026.103679","url":null,"abstract":"<div><div>The 2017 Marine Heatwave event was characterized by significant positive sea surface temperature anomalies driven by weakened and reversed wind patterns, from mid-January to mid-April. The wind reversal during the Coastal El Niño favored downwelling processes, limiting the upward transport of nutrient-rich waters and causing a rapid collapse in surface phytoplankton biomass. Additionally, reduced latent heat flux and increased shortwave radiation further exacerbated surface warming. From February to March 2017, chlorophyll-a concentrations showed strong negative anomalies (more than −3 mg m<sup>−3</sup>), with the High Productive Zone (HPZ) contracting significantly, from 300 km offshore in January to nearly 25 km from the coast during this two-months period, while the total HPZ area decreased by up to 130,000 km<sup>2</sup> in March, demonstrating a sharp decline in surface chlorophyll-a concentration. However, as physical drivers tend to return to typical seasonal values by April, upwelling resumed, positive chlorophyll-a anomalies emerged indicating a relatively rapid recovery of phytoplankton biomass, and the HPZ re-expanded toward climatological levels. These findings emphasize the sensitivity of the northern Peruvian marine ecosystem to short-term climate variability. Given the increasing frequency of these climatic events, understanding the physical drivers of ecosystem changes is critical for predicting future impacts and informing adaptive management strategies.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103679"},"PeriodicalIF":3.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995700","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 : 2026-01-16DOI: 10.1016/j.pocean.2026.103678
Fany Sardenne , Carl D. van der Lingen , Marie Vagner , Yonela Geja , Eleonora Puccinelli , Margaux Mathieu-Resuge , Fabienne Le Grand , Jean-Marie Munaron , Manon Buscaglia , Sandrine Serre , Philippe Soudant , Laure Pecquerie
Small pelagic fishes (SPF) in eastern boundary upwelling systems share space and must adapt to strong seasonal and inter-annual variations in their environment. This raises questions about how these species share food resources in a changing environment and whether they compete with each other when their food resources are reduced. We approach these questions on three SPF species (sardine Sardinops sagax, anchovy Engraulis encrasicolus and round herring Etrumeus whiteheadi) living on the west and south coasts of South Africa. We combined fish muscle fatty acid profiles as a proxy for prey taxa diversity, stable isotope compositions as a proxy for habitat and trophic position, and satellite-derived chlorophyll-a and zooplankton concentrations as proxies for food availability. We found that the total fatty acid content (energy reserve) of the three species increased with chlorophyll-a concentration, suggesting that chlorophyll-a is a good proxy for food quantity. For the three SPF species, the niche width increased with the amount of chlorophyll-a. However, the niche overlap (i.e. the potential for competition) remained relatively unchanged as chlorophyll-a concentrations increased, though it varied considerably depending on local conditions (from 0 to 100 %), higher on the west coast (influenced by the Benguela upwelling) than in the south coast. The relative trophic level of the species (round herring > anchovy > sardine) was confirmed in both regions and the round herring remained on average 25 % fattier than the other two species. These results suggest that on a relatively short time scale (month) SPF species are more selective when food levels decrease but that competition for resources may or may not operate depending on local conditions. However, integrated over a larger time scale, the three species do feed on different resources (resulting in different trophic levels) and cannot be considered an ecological substitute. The recent changes in their respective biomasses could impact the amount of fat (energy) available to higher trophic levels.
{"title":"Resource partitioning among small pelagic fish remains stable regardless of food availability in a seasonally pulsed upwelling system","authors":"Fany Sardenne , Carl D. van der Lingen , Marie Vagner , Yonela Geja , Eleonora Puccinelli , Margaux Mathieu-Resuge , Fabienne Le Grand , Jean-Marie Munaron , Manon Buscaglia , Sandrine Serre , Philippe Soudant , Laure Pecquerie","doi":"10.1016/j.pocean.2026.103678","DOIUrl":"10.1016/j.pocean.2026.103678","url":null,"abstract":"<div><div>Small pelagic fishes (SPF) in eastern boundary upwelling systems share space and must adapt to strong seasonal and inter-annual variations in their environment. This raises questions about how these species share food resources in a changing environment and whether they compete with each other when their food resources are reduced. We approach these questions on three SPF species (sardine <em>Sardinops sagax</em>, anchovy <em>Engraulis encrasicolus</em> and round herring <em>Etrumeus whiteheadi</em>) living on the west and south coasts of South Africa. We combined fish muscle fatty acid profiles as a proxy for prey taxa diversity, stable isotope compositions as a proxy for habitat and trophic position, and satellite-derived chlorophyll-a and zooplankton concentrations as proxies for food availability. We found that the total fatty acid content (energy reserve) of the three species increased with chlorophyll-a concentration, suggesting that chlorophyll-a is a good proxy for food quantity. For the three SPF species, the niche width increased with the amount of chlorophyll-a. However, the niche overlap (i.e. the potential for competition) remained relatively unchanged as chlorophyll-a concentrations increased, though it varied considerably depending on local conditions (from 0 to 100 %), higher on the west coast (influenced by the Benguela upwelling) than in the south coast. The relative trophic level of the species (round herring > anchovy > sardine) was confirmed in both regions and the round herring remained on average 25 % fattier than the other two species. These results suggest that on a relatively short time scale (month) SPF species are more selective when food levels decrease but that competition for resources may or may not operate depending on local conditions. However, integrated over a larger time scale, the three species do feed on different resources (resulting in different trophic levels) and cannot be considered an ecological substitute. The recent changes in their respective biomasses could impact the amount of fat (energy) available to higher trophic levels.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103678"},"PeriodicalIF":3.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995701","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 : 2026-01-16DOI: 10.1016/j.pocean.2025.103653
Natalia Cisternas , José Garcés-Vargas , Manuel I. Castillo , Carmen Barrios-Guzmán , Fernanda Barilari , Mauricio F. Landaeta , Maritza Sepúlveda , Andrea Piñones
The Chilean Patagonia, between 40°S and 56°S, hosts one of the world’s largest and most productive estuarine systems, where oceanic waters mix with freshwater from rivers, runoff, glaciers, and snowmelt, creating a complex and dynamic estuarine environment. Understanding the factors influencing salinity fluctuations in this region is key to elucidating its ecosystem complexity. This study evaluates the forcings driving salinity variability in the mixed layer of West Patagonia’s coastal zone. A salinity balance was done using GLORYS reanalysis and atmospheric variables from ERA5. Spatiotemporal variability of the salt balance terms was investigated using Hovmöller diagrams focusing on three key sites. Results showed significant seasonal and interannual variability in the mixed layer. Advective terms, particularly the zonal component, were crucial in modulating salinity. A clear annual cycle emerged in the northern sector (40–48°S). Empirical Orthogonal Function analysis identified significant interannual fluctuations, with positive atypical periods in 1997–2005 and 2010–2015, and negative periods in 2006–2008 and 2018–2020. These fluctuations were primarily linked to the dynamics of San Quintín Glacier (∼47°S), which induced anomalous salinity conditions along the coastal domain. Notably, these variations did not exhibit a direct relationship with large-scale climate modes. These findings underscore the intricate nature of salinity variability in West Patagonia’s coastal waters, driven by a complex interplay of local hydrological processes and glacial dynamics. Understanding these mechanisms is essential for anticipating future changes in this fragile and ecologically significant region.
{"title":"Salinity variability in the mixed layer off Chilean Patagonia: potential influence of Patagonian ice fields","authors":"Natalia Cisternas , José Garcés-Vargas , Manuel I. Castillo , Carmen Barrios-Guzmán , Fernanda Barilari , Mauricio F. Landaeta , Maritza Sepúlveda , Andrea Piñones","doi":"10.1016/j.pocean.2025.103653","DOIUrl":"10.1016/j.pocean.2025.103653","url":null,"abstract":"<div><div>The Chilean Patagonia, between 40°S and 56°S, hosts one of the world’s largest and most productive estuarine systems, where oceanic waters mix with freshwater from rivers, runoff, glaciers, and snowmelt, creating a complex and dynamic estuarine environment. Understanding the factors influencing salinity fluctuations in this region is key to elucidating its ecosystem complexity. This study evaluates the forcings driving salinity variability in the mixed layer of West Patagonia’s coastal zone. A salinity balance was done using GLORYS reanalysis and atmospheric variables from ERA5. Spatiotemporal variability of the salt balance terms was investigated using Hovmöller diagrams focusing on three key sites. Results showed significant seasonal and interannual variability in the mixed layer. Advective terms, particularly the zonal component, were crucial in modulating salinity. A clear annual cycle emerged in the northern sector (40–48°S). Empirical Orthogonal Function analysis identified significant interannual fluctuations, with positive atypical periods in 1997–2005 and 2010–2015, and negative periods in 2006–2008 and 2018–2020. These fluctuations were primarily linked to the dynamics of San Quintín Glacier (∼47°S), which induced anomalous salinity conditions along the coastal domain. Notably, these variations did not exhibit a direct relationship with large-scale climate modes. These findings underscore the intricate nature of salinity variability in West Patagonia’s coastal waters, driven by a complex interplay of local hydrological processes and glacial dynamics. Understanding these mechanisms is essential for anticipating future changes in this fragile and ecologically significant region.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103653"},"PeriodicalIF":3.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995702","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 : 2026-01-11DOI: 10.1016/j.pocean.2026.103668
Yao Lu , Huamao Yuan , Jinming Song , Xuegang Li , Liqin Duan , Qidong Wang , Fengmin Pan
The ocean annually absorbs approximately 2.9 GtC (gigatons of carbon), accounting for 26% of global CO2 emissions, making it a critical carbon sink. In this process, bacteria attached to particulate organic carbon (POC) play a pivotal role: they transform labile phytoplankton-derived carbon into more biochemically stable bacterial carbon, ultimately forming long-term storable refractory dissolved organic carbon (RDOC) and refractory particulate organic carbon (RPOC). Thus, the “refractory transformation” of marine organic carbon is a key mechanism in forming the biological carbon pump. Currently, the inventory, proportion, and microbial roles of RDOC have been preliminarily elucidated. However, the stock, sources, microbial transformation processes, underlying mechanisms of RPOC, and its contribution to long-term carbon sequestration remain unclear. Amino acids, as essential components of POC, have emerged as novel indicators—through their content, composition, and isotopic signatures—to effectively quantify microbial degradation and transformation of POC and decipher its stability mechanisms. This review systematically synthesizes research advances on the distribution and stability of POC across size classes under microbial mediation. It highlights the potential of amino acid-based techniques and compound-specific isotope analysis (CSIA) to unravel microbial contributions to RPOC formation and long-term carbon storage. Furthermore, a preliminary framework for quantifying the role of different POC size classes in marine carbon sequestration is proposed. This work provides a scientific basis for understanding the ocean’s role in achieving the “carbon neutrality” goal and establishes a theoretical foundation for advancing knowledge of “microbe–size class–carbon sequestration” coupled mechanisms and developing ocean-based carbon sequestration technologies.
{"title":"Stability of marine particulate organic matter under microbial mediation and its role in carbon sequestration","authors":"Yao Lu , Huamao Yuan , Jinming Song , Xuegang Li , Liqin Duan , Qidong Wang , Fengmin Pan","doi":"10.1016/j.pocean.2026.103668","DOIUrl":"10.1016/j.pocean.2026.103668","url":null,"abstract":"<div><div>The ocean annually absorbs approximately 2.9 GtC (gigatons of carbon), accounting for 26% of global CO<sub>2</sub> emissions, making it a critical carbon sink. In this process, bacteria attached to particulate organic carbon (POC) play a pivotal role: they transform labile phytoplankton-derived carbon into more biochemically stable bacterial carbon, ultimately forming long-term storable refractory dissolved organic carbon (RDOC) and refractory particulate organic carbon (RPOC). Thus, the “refractory transformation” of marine organic carbon is a key mechanism in forming the biological carbon pump. Currently, the inventory, proportion, and microbial roles of RDOC have been preliminarily elucidated. However, the stock, sources, microbial transformation processes, underlying mechanisms of RPOC, and its contribution to long-term carbon sequestration remain unclear. Amino acids, as essential components of POC, have emerged as novel indicators—through their content, composition, and isotopic signatures—to effectively quantify microbial degradation and transformation of POC and decipher its stability mechanisms. This review systematically synthesizes research advances on the distribution and stability of POC across size classes under microbial mediation. It highlights the potential of amino acid-based techniques and compound-specific isotope analysis (CSIA) to unravel microbial contributions to RPOC formation and long-term carbon storage. Furthermore, a preliminary framework for quantifying the role of different POC size classes in marine carbon sequestration is proposed. This work provides a scientific basis for understanding the ocean’s role in achieving the “carbon neutrality” goal and establishes a theoretical foundation for advancing knowledge of “microbe–size class–carbon sequestration” coupled mechanisms and developing ocean-based carbon sequestration technologies.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103668"},"PeriodicalIF":3.6,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956568","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 : 2026-01-08DOI: 10.1016/j.pocean.2025.103664
Marc Tedetti , Catherine Guigue , Léo Mahieu , Pauline L. Martinot , Mar Benavides , Cécile Dupouy , Sandra Nunige , Elvira Pulido-Villena , Céline Dimier , Chloé Tilliette , Sophie Bonnet , Cécile Guieu , Dominique Lefèvre
The Western Tropical South Pacific has recently been identified as a global hotspot for microbial dinitrogen fixation and shallow hydrothermal activity, yet the dynamics of dissolved organic matter (DOM) in this ecosystem remains understudied. During the TONGA cruise (2019), we investigated the distribution of dissolved organic carbon (DOC), chromophoric DOM (CDOM) and fluorescent DOM (FDOM) from Melanesian waters to the South Pacific Gyre, including the Lau Basin/Tonga-Kermadec Volcanic Arc. DOC concentration, CDOM absorption [aCDOM(254)], the CDOM spectral slope (S275-295) and tyrosine-like fluorescence decreased from surface to deep waters across subregions. In contrast, apparent oxygen utilization (AOU), nutrients, aCDOM(350), specific UV absorbance (SUVA254), humic-like fluorescence, humification (HIX) and combustion (COX) indices increased with depth. These distributions reveal 1) the production of labile, low molecular weight DOM by phytoplankton, and photobleaching in the photic layer, and 2) the production of higher molecular weight, bio-refractory DOM from the remineralization of sinking particulate organic carbon and DOC in deeper waters. Also, the tryptophan-like fluorescence peaks at depth could be associated with the presence of sinking Trichodesmium spp. Regional variations in DOM characteristics were less pronounced than water-mass-related differences but revealed subtle trends along the west-east gradient, with overall higher DOC, CDOM and FDOM levels in the Melanesian and Lau Basin/Arc subregions compared to the South Pacific Gyre. At 200-m depth near the Arc, the release of hydrothermal fluids altered the DOM composition close to the vent, with significant increases in aCDOM(254) and tyrosine-like material, and significant decreases in HIX and COX indices. We further show an indirect, large-scale impact of shallow hydrothermal vents on the DOM stock in the 0–50-m surface layer, driven by the iron fertilization-induced stimulation of planktonic activity in the photic zone. The increased DOM stocks were observed mostly in the Lau Basin/Arc subregion but extending to Melanesian waters and the western edge of South Pacific Gyre. Collectively, these processes shape the optical properties and biogeochemical behavior of DOM, highlighting the importance of hydrothermal systems in the oceanic carbon cycle.
{"title":"Dissolved organic matter (DOC, CDOM, FDOM) in the western Tropical South Pacific: Depth- and subregion-resolved variability, and hydrothermal influence","authors":"Marc Tedetti , Catherine Guigue , Léo Mahieu , Pauline L. Martinot , Mar Benavides , Cécile Dupouy , Sandra Nunige , Elvira Pulido-Villena , Céline Dimier , Chloé Tilliette , Sophie Bonnet , Cécile Guieu , Dominique Lefèvre","doi":"10.1016/j.pocean.2025.103664","DOIUrl":"10.1016/j.pocean.2025.103664","url":null,"abstract":"<div><div>The Western Tropical South Pacific has recently been identified as a global hotspot for microbial dinitrogen fixation and shallow hydrothermal activity, yet the dynamics of dissolved organic matter (DOM) in this ecosystem remains understudied. During the TONGA cruise (2019), we investigated the distribution of dissolved organic carbon (DOC), chromophoric DOM (CDOM) and fluorescent DOM (FDOM) from Melanesian waters to the South Pacific Gyre, including the Lau Basin/Tonga-Kermadec Volcanic Arc. DOC concentration, CDOM absorption [a<sub>CDOM</sub>(254)], the CDOM spectral slope (S<sub>275-295</sub>) and tyrosine-like fluorescence decreased from surface to deep waters across subregions. In contrast, apparent oxygen utilization (AOU), nutrients, a<sub>CDOM</sub>(350), specific UV absorbance (SUVA<sub>254</sub>), humic-like fluorescence, humification (HIX) and combustion (COX) indices increased with depth. These distributions reveal 1) the production of labile, low molecular weight DOM by phytoplankton, and photobleaching in the photic layer, and 2) the production of higher molecular weight, bio-refractory DOM from the remineralization of sinking particulate organic carbon and DOC in deeper waters. Also, the tryptophan-like fluorescence peaks at depth could be associated with the presence of sinking <em>Trichodesmium</em> spp. Regional variations in DOM characteristics were less pronounced than water-mass-related differences but revealed subtle trends along the west-east gradient, with overall higher DOC, CDOM and FDOM levels in the Melanesian and Lau Basin/Arc subregions compared to the South Pacific Gyre. At 200-m depth near the Arc, the release of hydrothermal fluids altered the DOM composition close to the vent, with significant increases in a<sub>CDOM</sub>(254) and tyrosine-like material, and significant decreases in HIX and COX indices. We further show an indirect, large-scale impact of shallow hydrothermal vents on the DOM stock in the 0–50-m surface layer, driven by the iron fertilization-induced stimulation of planktonic activity in the photic zone. The increased DOM stocks were observed mostly in the Lau Basin/Arc subregion but extending to Melanesian waters and the western edge of South Pacific Gyre. Collectively, these processes shape the optical properties and biogeochemical behavior of DOM, highlighting the importance of hydrothermal systems in the oceanic carbon cycle.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103664"},"PeriodicalIF":3.6,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979188","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 : 2026-01-06DOI: 10.1016/j.pocean.2025.103666
Jun Ma , Lilian Wen , Xuegang Li , Kuidong Xu , Jiajia Dai , Yi Sun , Guorong Zhong , Detong Tian , Huamao Yuan , Liqin Duan , Jinming Song
Seamount and the oxygen minimum zone (OMZ) are often two typical habitats coexisting in the deep sea, and studying the relationship between the “seamount effect” and OMZ is of great significance to improve the cognitive level of the two typical deep-sea habitats. Based on the investigation of the two cruises in the M4 seamount of the Western Pacific, this study revealed the “seamount effect”, explored the impact of seamount and environmental parameters on OMZ. The results showed that the uplifts of the isohaline, isotherm and isopycnal occurred near the summit in the two cruises, and the isolines of NO3-N, PO4-P and NO2-N were also elevated near the summit. Meanwhile, the ratio of the average concentration of POC near the summit for cruise 1 to cruise 2 can reach up to about 2 times. This may indicate that there was a “seamount effect” in both cruises, and it was stronger in cruise 1. The range and intensity of OMZ in both cruises were similar, with the range of 550–1100 m and (330–380, 850–1100) m, respectively. The impact of seamount on OMZ may be reflected in two aspects. One possible mechanism was that the hydrological phenomena such as upwelling near the summit may raise the isolines of low concentration DO in 200–300 m, increasing the range of the upper boundary of OMZ; Another possibility was that the biological activities of seamount sediments continuously may consume DO, such as in 1000 m at station A7 of cruise 1, increasing the intensity of OMZ. In addition, the temperature below 1000 m directly controlled the upper boundary of OMZ, while the decomposition of organic matter in 75–300 m above the OMZ consumed DO, which also had an important impact on the range and intensity of the OMZ.
{"title":"Potential impact of seamount on the mild oxygen minimum zone (OMZ) in the Western Pacific","authors":"Jun Ma , Lilian Wen , Xuegang Li , Kuidong Xu , Jiajia Dai , Yi Sun , Guorong Zhong , Detong Tian , Huamao Yuan , Liqin Duan , Jinming Song","doi":"10.1016/j.pocean.2025.103666","DOIUrl":"10.1016/j.pocean.2025.103666","url":null,"abstract":"<div><div>Seamount and the oxygen minimum zone (OMZ) are often two typical habitats coexisting in the deep sea, and studying the relationship between the “seamount effect” and OMZ is of great significance to improve the cognitive level of the two typical deep-sea habitats. Based on the investigation of the two cruises in the M4 seamount of the Western Pacific, this study revealed the “seamount effect”, explored the impact of seamount and environmental parameters on OMZ. The results showed that the uplifts of the isohaline, isotherm and isopycnal occurred near the summit in the two cruises, and the isolines of NO<sub>3</sub>-N, PO<sub>4</sub>-P and NO<sub>2</sub>-N were also elevated near the summit. Meanwhile, the ratio of the average concentration of POC near the summit for cruise 1 to cruise 2 can reach up to about 2 times. This may indicate that there was a “seamount effect” in both cruises, and it was stronger in cruise 1. The range and intensity of OMZ in both cruises were similar, with the range of 550–1100 m and (330–380, 850–1100) m, respectively. The impact of seamount on OMZ may be reflected in two aspects. One possible mechanism was that the hydrological phenomena such as upwelling near the summit may raise the isolines of low concentration DO in 200–300 m, increasing the range of the upper boundary of OMZ; Another possibility was that the biological activities of seamount sediments continuously may consume DO, such as in 1000 m at station A7 of cruise 1, increasing the intensity of OMZ. In addition, the temperature below 1000 m directly controlled the upper boundary of OMZ, while the decomposition of organic matter in 75–300 m above the OMZ consumed DO, which also had an important impact on the range and intensity of the OMZ.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103666"},"PeriodicalIF":3.6,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940881","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 : 2026-01-06DOI: 10.1016/j.pocean.2026.103667
Xiangyan Yang , Robyn Linner , Cameron Hodgdon , Jacob P. Kritzer , George Maynard , Erin Pelletier , Yong Chen
Oceanographic information is critical for understanding the capacity of a given habitat to support a certain species. Habitat Suitability Index (HSI) models are widely used to describe the relative suitability of an area by defining the relationship between key environmental variables and the species’ abundance. The Gulf of Maine (GOM) region provides essential habitat for American lobster (Homarus americanus) and has been identified as one of the most rapidly warming ocean ecosystems in the world. Understanding how climate change may influence American lobster habitat is imperative in planning for an uncertain future and informing the lobster industry and management. However, a lack and lag of bottom temperature (BT) data availability has impeded the development and operationalization of projected lobster suitable habitat. In this study, we first examined the ability of sea surface temperature (SST) in representing the spatiotemporal variability of BT in the GOM. We then compared the suitability index (SI) curves and HSI maps generated by each temperature dataset. Finally, we assessed the correlation level of the predicted HSI values with lobster abundance. Our study demonstrated that the SST-based model effectively captures the general spatial patterns of suitable habitats predicted by the BT-based model. However, the performance of the SST-based model when compared to the BT-based model was less consistent across seasons and between eastern and western GOM regions, which may be attributed to the seasonal stratification and nearshore physical oceanographic dynamics. The SST-based HSI model had a slightly higher correlation with observed abundance data at most depth intervals and particularly in recent fall periods. Our findings suggest that in less stratified regions, SST can serve as a reasonable alternative to BT and may even provide a more responsive indicator of warming. Leveraging data-rich SST in lobster HSI models can enhance the operationalization of habitat projections and support timely management responses under these conditions. However, in stratified regions, reliance on SST alone may underestimate suitable habitat. As ocean stratification may intensify under climate change, further evaluation of the alternative validity is warranted. The methodology and analysis framework of this study can also be applied to other species and areas where limited BT observations constrain habitat modeling and stratification is short-lived, allowing for more prompt identification of and response to climate impacts.
{"title":"Evaluating the validity of using sea surface temperature as an alternative to bottom temperature in American lobster habitat suitability modeling","authors":"Xiangyan Yang , Robyn Linner , Cameron Hodgdon , Jacob P. Kritzer , George Maynard , Erin Pelletier , Yong Chen","doi":"10.1016/j.pocean.2026.103667","DOIUrl":"10.1016/j.pocean.2026.103667","url":null,"abstract":"<div><div>Oceanographic information is critical for understanding the capacity of a given habitat to support a certain species. Habitat Suitability Index (HSI) models are widely used to describe the relative suitability of an area by defining the relationship between key environmental variables and the species’ abundance. The Gulf of Maine (GOM) region provides essential habitat for American lobster (<em>Homarus americanus</em>) and has been identified as one of the most rapidly warming ocean ecosystems in the world. Understanding how climate change may influence American lobster habitat is imperative in planning for an uncertain future and informing the lobster industry and management. However, a lack and lag of bottom temperature (BT) data availability has impeded the development and operationalization of projected lobster suitable habitat. In this study, we first examined the ability of sea surface temperature (SST) in representing the spatiotemporal variability of BT in the GOM. We then compared the suitability index (SI) curves and HSI maps generated by each temperature dataset. Finally, we assessed the correlation level of the predicted HSI values with lobster abundance. Our study demonstrated that the SST-based model effectively captures the general spatial patterns of suitable habitats predicted by the BT-based model. However, the performance of the SST-based model when compared to the BT-based model was less consistent across seasons and between eastern and western GOM regions, which may be attributed to the seasonal stratification and nearshore physical oceanographic dynamics. The SST-based HSI model had a slightly higher correlation with observed abundance data at most depth intervals and particularly in recent fall periods. Our findings suggest that in less stratified regions, SST can serve as a reasonable alternative to BT and may even provide a more responsive indicator of warming. Leveraging data-rich SST in lobster HSI models can enhance the operationalization of habitat projections and support timely management responses under these conditions. However, in stratified regions, reliance on SST alone may underestimate suitable habitat. As ocean stratification may intensify under climate change, further evaluation of the alternative validity is warranted. The methodology and analysis framework of this study can also be applied to other species and areas where limited BT observations constrain habitat modeling and stratification is short-lived, allowing for more prompt identification of and response to climate impacts.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103667"},"PeriodicalIF":3.6,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940800","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 : 2026-01-05DOI: 10.1016/j.pocean.2025.103665
José Garcés-Vargas , Andrea Piñones , Wolfgang Schneider , Mauricio F. Landaeta , Manuel I. Castillo , Natalia Cisternas , Carmen Barrios-Guzmán , Fernanda Barilari
Circulation along the west coast of South America originates from the eastward-flowing South Pacific Current, which bifurcates around 40-45°S. Its northern branch forms the Humboldt Current (HC), while the southern branch continues along the continental shelf as the Cape Horn Current (CHC). Despite significant scientific efforts to understand the HC, the CHC has received considerably less attention. This study investigates the spatial structure, seasonal variability, and forcing mechanisms of the CHC using a combination of reanalysis data (GLORYS12, ERA5) and in-situ observations. Our results reveal that the CHC’s dynamics are governed by the superposition of two distinct physical mechanisms with different vertical structures: a surface-intensified response to direct wind forcing, and a vertically-coherent geostrophic flow driven by sea surface height gradients. This dual structure explains both the year-round persistence of the current, due to its deep geostrophic core, and its seasonal cycle. The current exhibits a modest but consistent intensification during austral summer and spring, with mean velocities increasing from ∼ 16 cm s−1 in autumn/winter to ∼ 18 cm s−1 in the warmer seasons, a variability primarily associated with the surface wind-driven component. Correlation analysis confirms that wind and sea surface height gradients are the dominant forcings, particularly in the CHC core region (51°–56°S). Furthermore, the underlying physical mechanism is consistent with a coastal downwelling process, where persistent alongshore winds ultimately maintain the large-scale pressure gradient. In comparison with the Alaska Current, the CHC shows similarities in its wind-driven dynamics but differs in its largely barotropic geostrophic structure, in contrast to the strong baroclinic influence of freshwater in the Gulf of Alaska. Our findings clarify the dual nature of the CHC, highlighting its role as a key pathway in the Patagonian shelf-break region, which in turn influences regional climate, marine ecosystems, and biogeochemical cycles. Future research should focus on the interaction of these components using high-resolution hydrodynamic models to better elucidate its variability.
南美洲西海岸的环流源于向东流动的南太平洋洋流，该洋流在南纬40-45度左右分叉。它的北部分支形成洪堡流（HC），而南部分支继续沿着大陆架形成合恩角流（CHC）。尽管在了解HC方面做出了重大的科学努力，但CHC受到的关注却少得多。利用再分析资料（GLORYS12、ERA5）和原位观测资料，对CHC的空间结构、季节变化和强迫机制进行了研究。研究结果表明，CHC的动力学受两种不同垂直结构的物理机制的叠加控制：地表对直接风强迫的强化响应和海面高度梯度驱动的垂直相干地转流。这种双重结构既解释了洋流的全年持续，因为它的深层地转核心，也解释了它的季节性循环。在南方夏季和春季，洋流表现出适度但持续的增强，平均速度从秋冬季的~ 16 cm s - 1增加到温暖季节的~ 18 cm s - 1，这种变化主要与地面风驱动分量有关。相关分析证实，风和海面高度梯度是主要强迫，特别是在CHC核心区（51°~ 56°S）。此外，潜在的物理机制与沿海下沉过程一致，持续的沿海风最终维持了大范围的压力梯度。与阿拉斯加流相比，CHC在风驱动动力方面表现出相似之处，但在主要的正压地转结构上有所不同，而阿拉斯加湾则受到淡水的强烈斜压影响。我们的研究结果阐明了CHC的双重性质，强调了它作为巴塔哥尼亚大陆架断裂区域的关键途径的作用，这反过来影响了区域气候、海洋生态系统和生物地球化学循环。未来的研究应集中在这些成分的相互作用，使用高分辨率的水动力学模型，以更好地阐明其变异性。
{"title":"Seasonal dynamics and forcing mechanisms of the Cape Horn Current: insights from reanalysis data and hydrographic observations","authors":"José Garcés-Vargas , Andrea Piñones , Wolfgang Schneider , Mauricio F. Landaeta , Manuel I. Castillo , Natalia Cisternas , Carmen Barrios-Guzmán , Fernanda Barilari","doi":"10.1016/j.pocean.2025.103665","DOIUrl":"10.1016/j.pocean.2025.103665","url":null,"abstract":"<div><div>Circulation along the west coast of South America originates from the eastward-flowing South Pacific Current, which bifurcates around 40-45°S. Its northern branch forms the Humboldt Current (HC), while the southern branch continues along the continental shelf as the Cape Horn Current (CHC). Despite significant scientific efforts to understand the HC, the CHC has received considerably less attention. This study investigates the spatial structure, seasonal variability, and forcing mechanisms of the CHC using a combination of reanalysis data (GLORYS12, ERA5) and <em>in-situ</em> observations. Our results reveal that the CHC’s dynamics are governed by the superposition of two distinct physical mechanisms with different vertical structures: a surface-intensified response to direct wind forcing, and a vertically-coherent geostrophic flow driven by sea surface height gradients. This dual structure explains both the year-round persistence of the current, due to its deep geostrophic core, and its seasonal cycle. The current exhibits a modest but consistent intensification during austral summer and spring, with mean velocities increasing from ∼ 16 cm s<sup>−1</sup> in autumn/winter to ∼ 18 cm s<sup>−1</sup> in the warmer seasons, a variability primarily associated with the surface wind-driven component. Correlation analysis confirms that wind and sea surface height gradients are the dominant forcings, particularly in the CHC core region (51°–56°S). Furthermore, the underlying physical mechanism is consistent with a coastal downwelling process, where persistent alongshore winds ultimately maintain the large-scale pressure gradient. In comparison with the Alaska Current, the CHC shows similarities in its wind-driven dynamics but differs in its largely barotropic geostrophic structure, in contrast to the strong baroclinic influence of freshwater in the Gulf of Alaska. Our findings clarify the dual nature of the CHC, highlighting its role as a key pathway in the Patagonian shelf-break region, which in turn influences regional climate, marine ecosystems, and biogeochemical cycles. Future research should focus on the interaction of these components using high-resolution hydrodynamic models to better elucidate its variability.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"242 ","pages":"Article 103665"},"PeriodicalIF":3.6,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903480","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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