Pub 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":"2025-12-09","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 : 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":"2025-12-05","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}
Pub Date : 2025-12-04DOI: 10.1016/j.pocean.2025.103634
Jee-Hoon Kim , Yuya Hibino , Eun Jin Yang , Kyoung-Ho Cho , Hyoung Sul La , Sung-Ho Kang , Jeong-Hyun Kim , Hyeju Yoo , Jong-Kuk Moon , Yoshiyuki Abe , Nanami Hosoda , Atsushi Yamaguchi , Kohei Matsuno
The Arctic marine ecosystem is undergoing a major, rapid transformation driven by climate change, resulting in complex and unpredictable shifts in zooplankton communities, which are key pelagic food web components. We synthesized extensive multi-year zooplankton datasets (2008–2021) collected by a Korean icebreaker research vessel (IBRV Araon; August 2016–2021) and a Japanese research vessel (RV Mirai; September 2008, 2010, 2012–2017, and 2021) in the western Arctic Ocean to examine the effects of environmental factors on zooplankton distribution. We determined the effect of key environmental variables, including integrated mean temperature, mean salinity, and fluorescence, on zooplankton community structure. We identified six distinct zooplankton communities shaped by regional characteristics and interannual oceanographic variability. The pronounced seasonal transition of zooplankton communities from summer to autumn, particularly in the Chukchi Sea and the Chukchi Borderland in 2017 and 2021, was the major finding. During summer, Pacific water inflow into the Chukchi Sea significantly increased Pacific species (e.g., Metridia pacifica) and meroplankton (e.g., barnacle larvae), with barnacle larvae extending into the Chukchi Borderland in 2017 and 2021. Although small species (e.g., Pseudocalanus spp.) remained dominant during the summer, but no clear increasing trend was observed in total abundance within the Chukchi Sea. By September, these Pacific Ocean–influenced communities had decreased rapidly, suggesting their high environmental dependency and incomplete establishment in the region. This study integrates multi-year, seasonally diverse datasets collected across a broad spatial range, providing a comprehensive understanding of how Arctic zooplankton respond to climate-induced environmental changes.
{"title":"Synthesis of spatiotemporal variability in western Arctic zooplankton communities from summer to fall during 2008–2021","authors":"Jee-Hoon Kim , Yuya Hibino , Eun Jin Yang , Kyoung-Ho Cho , Hyoung Sul La , Sung-Ho Kang , Jeong-Hyun Kim , Hyeju Yoo , Jong-Kuk Moon , Yoshiyuki Abe , Nanami Hosoda , Atsushi Yamaguchi , Kohei Matsuno","doi":"10.1016/j.pocean.2025.103634","DOIUrl":"10.1016/j.pocean.2025.103634","url":null,"abstract":"<div><div>The Arctic marine ecosystem is undergoing a major, rapid transformation driven by climate change, resulting in complex and unpredictable shifts in zooplankton communities, which are key pelagic food web components. We synthesized extensive multi-year zooplankton datasets (2008–2021) collected by a Korean icebreaker research vessel (IBRV Araon; August 2016–2021) and a Japanese research vessel (RV Mirai; September 2008, 2010, 2012–2017, and 2021) in the western Arctic Ocean to examine the effects of environmental factors on zooplankton distribution. We determined the effect of key environmental variables, including integrated mean temperature, mean salinity, and fluorescence, on zooplankton community structure. We identified six distinct zooplankton communities shaped by regional characteristics and interannual oceanographic variability. The pronounced seasonal transition of zooplankton communities from summer to autumn, particularly in the Chukchi Sea and the Chukchi Borderland in 2017 and 2021, was the major finding. During summer, Pacific water inflow into the Chukchi Sea significantly increased Pacific species (e.g., Metridia pacifica) and meroplankton (e.g., barnacle larvae), with barnacle larvae extending into the Chukchi Borderland in 2017 and 2021. Although small species (e.g., <em>Pseudocalanus</em> spp.) remained dominant during the summer, but no clear increasing trend was observed in total abundance within the Chukchi Sea. By September, these Pacific Ocean–influenced communities had decreased rapidly, suggesting their high environmental dependency and incomplete establishment in the region. This study integrates multi-year, seasonally diverse datasets collected across a broad spatial range, providing a comprehensive understanding of how Arctic zooplankton respond to climate-induced environmental changes.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103634"},"PeriodicalIF":3.6,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-26DOI: 10.1016/j.pocean.2025.103633
Tom Reich , Natalia Belkin , Guy Sisma-Ventura , Hagar Hauzer , Ilana Berman-Frank , Eyal Rahav
We investigated the spatiotemporal variability of photosynthesis and dark carbon fixation (DCF) in the photic layer of the eastern Mediterranean Sea (EMS). Our results show that the contribution of DCF to primary productivity (PP) was generally low in the coastal area (typically ∼ 2–4 %) and higher offshore (often ≥ 10 %). We show that the contribution of DCF to PP was higher during the thermally-stratified summer period (low nutrient availability) when heterotrophic microbial metabolism prevailed compared to the thermally-mixed winter period (higher nutrient availability) when photoautotrophy predominated. Depth-integrated DCF contributed ∼ 5 g C m−2 y−1 at both offshore and coastal waters, which was ∼ 3.5–11 % of the annual photic zone PP. Our results substantiate previous studies indicating that inorganic carbon fixation by chemoautotrophs should be considered and included in production estimates, especially in low production areas and in systems where oligotrophy is expanding, such as the subtropical and tropical oceans.
研究了东地中海（EMS）光层光合作用和暗碳固定（DCF）的时空变异性。我们的研究结果表明，DCF对初级生产力（PP）的贡献在沿海地区普遍较低（通常为~ 2 - 4%），而在近海地区则较高（通常≥10%）。结果表明，在异养微生物代谢为主的热分层夏季（营养有效性低），DCF对PP的贡献高于光自养为主的热混合冬季（营养有效性高）。在近海和沿海水域，深度综合DCF贡献了~ 5 g cm - 2 y - 1，占每年光区PP的~ 3.5 - 11%。我们的结果证实了之前的研究，表明在产量估算中应考虑并包括化能自养生物的无机碳固定，特别是在低产量地区和低营养扩大的系统中，如亚热带和热带海洋。
{"title":"Does oligotrophy favor chemoautotrophy over photoautotrophy?","authors":"Tom Reich , Natalia Belkin , Guy Sisma-Ventura , Hagar Hauzer , Ilana Berman-Frank , Eyal Rahav","doi":"10.1016/j.pocean.2025.103633","DOIUrl":"10.1016/j.pocean.2025.103633","url":null,"abstract":"<div><div>We investigated the spatiotemporal variability of photosynthesis and dark carbon fixation (DCF) in the photic layer of the eastern Mediterranean Sea (EMS). Our results show that the contribution of DCF to primary productivity (PP) was generally low in the coastal area (typically ∼ 2–4 %) and higher offshore (often ≥ 10 %). We show that the contribution of DCF to PP was higher during the thermally-stratified summer period (low nutrient availability) when heterotrophic microbial metabolism prevailed compared to the thermally-mixed winter period (higher nutrient availability) when photoautotrophy predominated. Depth-integrated DCF contributed ∼ 5 g C m<sup>−2</sup> y<sup>−1</sup> at both offshore and coastal waters, which was ∼ 3.5–11 % of the annual photic zone PP. Our results substantiate previous studies indicating that inorganic carbon fixation by chemoautotrophs should be considered and included in production estimates, especially in low production areas and in systems where oligotrophy is expanding, such as the subtropical and tropical oceans.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103633"},"PeriodicalIF":3.6,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145609402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-26DOI: 10.1016/j.pocean.2025.103630
Kay I. Ohshima , Mamoru Ohshima , Masato Ito , Kazuki Nakata , Mizuki Kuga , Kohei Matsuno , Atsushi Yamaguchi
Acoustic Doppler Current Profilers (ADCPs) provide backscatter strength data, which can be used to detect suspended materials in the water column. This study developed a novel approach to detect and distinguish between zooplankton diel vertical migration (DVM) and sediment resuspension by applying Complex Empirical Orthogonal Function (CEOF) analysis to 24-hour bandpass-filtered ADCP backscatter data. The temporal CEOF mode scores serve as objective scalar indices of the intensity of each phenomenon, enabling quantitative comparisons with environmental factors. We applied this approach to year-round ADCP array observations in the western Sea of Okhotsk. At most sites, DVM activity is represented by the first CEOF mode. Temporal variations of the first mode revealed that, during the sea-ice season, DVM significantly weakens over shelf regions but persists in offshore regions, even though shelf regions exhibit more active biological productivity than offshore regions during the warm season. This contrasting seasonal behavior likely reflects differences in the dominant zooplankton species and their traits. The quantitative assessment of our method revealed clear relationships with tidal currents through spectral analysis. In the northwestern Okhotsk Sea, where tidal currents are strong, DVM activity, represented by the first mode, was consistently reduced during spring tides. At Kashevarov Bank, where tidal currents exceed 1 m/s, the first mode represents sediment resuspension and intensifies ∼ 1–1.5 days after peak tidal current velocities, and the second mode captures DVM. Given the vast quantity of unused ADCP backscatter data worldwide, the method proposed here can help unlock the potential of these dormant datasets.
{"title":"Zooplankton diel vertical migration and sediment resuspension detected from CEOF analysis of ADCP backscatter in the western Sea of Okhotsk","authors":"Kay I. Ohshima , Mamoru Ohshima , Masato Ito , Kazuki Nakata , Mizuki Kuga , Kohei Matsuno , Atsushi Yamaguchi","doi":"10.1016/j.pocean.2025.103630","DOIUrl":"10.1016/j.pocean.2025.103630","url":null,"abstract":"<div><div>Acoustic Doppler Current Profilers (ADCPs) provide backscatter strength data, which can be used to detect suspended materials in the water column. This study developed a novel approach to detect and distinguish between zooplankton diel vertical migration (DVM) and sediment resuspension by applying Complex Empirical Orthogonal Function (CEOF) analysis to 24-hour bandpass-filtered ADCP backscatter data. The temporal CEOF mode scores serve as objective scalar indices of the intensity of each phenomenon, enabling quantitative comparisons with environmental factors. We applied this approach to year-round ADCP array observations in the western Sea of Okhotsk. At most sites, DVM activity is represented by the first CEOF mode. Temporal variations of the first mode revealed that, during the sea-ice season, DVM significantly weakens over shelf regions but persists in offshore regions, even though shelf regions exhibit more active biological productivity than offshore regions during the warm season. This contrasting seasonal behavior likely reflects differences in the dominant zooplankton species and their traits. The quantitative assessment of our method revealed clear relationships with tidal currents through spectral analysis. In the northwestern Okhotsk Sea, where tidal currents are strong, DVM activity, represented by the first mode, was consistently reduced during spring tides. At Kashevarov Bank, where tidal currents exceed 1 m/s, the first mode represents sediment resuspension and intensifies ∼ 1–1.5 days after peak tidal current velocities, and the second mode captures DVM. Given the vast quantity of unused ADCP backscatter data worldwide, the method proposed here can help unlock the potential of these dormant datasets.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103630"},"PeriodicalIF":3.6,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145609426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-25DOI: 10.1016/j.pocean.2025.103632
Airam N. Sarmiento-Lezcano , María Couret , Javier Díaz-Pérez , Ainhoa Bernal , Vanesa Raya , Martín Pla , Nicolás Larrumbide-Zúñiga , Arturo Castellón , Santiago Hernández-León
Pyrosomes are colonial tunicates that inhabit diverse environments and perform diel vertical migrations, contributing to the downward carbon flux primarily through large fecal pellet production and carcass depositions. Pyrosoma atlanticum is the most widespread pelagic colonial tunicate worldwide, yet its role in the carbon cycle remains poorly understood. Here, we investigated the abundance, biomass, and contribution of P. atlanticum colonies to the biological carbon pump using MOCNESS and Mesopelagos nets in the subtropical waters off the Northwest African upwelling transition zone. We found two different areas within the studied zone: a highly productive area off the African coast and an oligotrophic area. We only found P. atlanticum near and in the productive area. Organisms sampled with the MOCNESS showed a narrower size distribution (colony length of 23.1 ± 12.4 mm) associated with the lower productivity area. By contrast, the Mesopelagos captured a wider size community (colony length of 106.5 ± 74.5 mm). Off the African coast, migrant biomass of small-sized organisms exhibited values almost 2-fold higher compared to the large-sized organisms (121 vs 77.1 mgC·m−2). In oligotrophic waters, where only small-sized organisms were captured, their migrant biomass reached values four times higher (493 mgC·m−2). Two approaches were used to estimate large-sized pyrosomes active flux: (1) the enzymatic activity of the electron transfer system (ETS) and (2) a specific respiration equation (RC) for P. atlanticum. In the productive area, both methods yielded similar values for large-sized organisms (ETS: 2.02 mgC·m−2·d–1 and RC: 1.93 mgC·m−2·d–1). Small-sized organisms were quite abundant in the oligotrophic station showing a RC of 3.03 mgC·m−2·d–1. Active flux by P. atlanticum ranged between 1.93 near the upwelling zone and 12.36 mgC·m−2·d–1 in oligotrophic waters due to their quite high biomass there. Our finding highlights the functional role of this large zooplanktonic and micronektonic fauna in the biological carbon export according to the productivity of the area.
{"title":"Active carbon flux by Pyrosoma atlanticum in the Northwest African upwelling transition zone (North-Central Eastern Atlantic Ocean)","authors":"Airam N. Sarmiento-Lezcano , María Couret , Javier Díaz-Pérez , Ainhoa Bernal , Vanesa Raya , Martín Pla , Nicolás Larrumbide-Zúñiga , Arturo Castellón , Santiago Hernández-León","doi":"10.1016/j.pocean.2025.103632","DOIUrl":"10.1016/j.pocean.2025.103632","url":null,"abstract":"<div><div>Pyrosomes are colonial tunicates that inhabit diverse environments and perform diel vertical migrations, contributing to the downward carbon flux primarily through large fecal pellet production and carcass depositions. <em>Pyrosoma atlanticum</em> is the most widespread pelagic colonial tunicate worldwide, yet its role in the carbon cycle remains poorly understood. Here, we investigated the abundance, biomass, and contribution of <em>P. atlanticum</em> colonies to the biological carbon pump using MOCNESS and Mesopelagos nets in the subtropical waters off the Northwest African upwelling transition zone. We found two different areas within the studied zone: a highly productive area off the African coast and an oligotrophic area. We only found <em>P. atlanticum</em> near and in the productive area. Organisms sampled with the MOCNESS showed a narrower size distribution (colony length of 23.1 ± 12.4 mm) associated with the lower productivity area. By contrast, the Mesopelagos captured a wider size community (colony length of 106.5 ± 74.5 mm). Off the African coast, migrant biomass of small-sized organisms exhibited values almost 2-fold higher compared to the large-sized organisms (121 vs 77.1 mgC·m<sup>−2</sup>). In oligotrophic waters, where only small-sized organisms were captured, their migrant biomass reached values four times higher (493 mgC·m<sup>−2</sup>). Two approaches were used to estimate large-sized pyrosomes active flux: (1) the enzymatic activity of the electron transfer system (ETS) and (2) a specific respiration equation (RC) for <em>P. atlanticum</em>. In the productive area, both methods yielded similar values for large-sized organisms (ETS: 2.02 mgC·m<sup>−2</sup>·d<sup>–1</sup> and RC: 1.93 mgC·m<sup>−2</sup>·d<sup>–1</sup>). Small-sized organisms were quite abundant in the oligotrophic station showing a RC of 3.03 mgC·m<sup>−2</sup>·d<sup>–1</sup>. Active flux by <em>P. atlanticum</em> ranged between 1.93 near the upwelling zone and 12.36 mgC·m<sup>−2</sup>·d<sup>–1</sup> in oligotrophic waters due to their quite high biomass there. Our finding highlights the functional role of this large zooplanktonic and micronektonic fauna in the biological carbon export according to the productivity of the area.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103632"},"PeriodicalIF":3.6,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145598713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-25DOI: 10.1016/j.pocean.2025.103627
Marco B. Sindlev , John P. Balmonte , Frank Wenzhöfer , Wenjie Xiao , Peter Stief , Kazumasa Oguri , Masashi Tsuchiya , Yusuke Yokoyama , Arka Rudra , Donald E. Canfield , Hamed Sanei , Angelika Brandt , Ronnie N. Glud
Sedimentological, mineralogical, chronological and basic biogeochemistry document that the Aleutian Trench region consists of four distinct regions, each with their respective benthic habitat, deposition dynamics, and material sourcing: the Northern Aleutian Slope (NS), Aleutian Trench – Axis (AT-A), Aleutian Trench – South Slope (AT-SS), and Southern Aleutian Slope (SS). The carbon pool is characterized by pyrolysis derived hydrogen and oxygen indices (HI and OI), radionuclides (Δ14C) and stable isotopes (δ13C-values), clearly varying among the respective regions. The NS has elevated total organic carbon (TOC) content, including distinct imprint of fresh, marine-derived organics originating from upwelling in the Gulf of Alaska with subsequent westward transport by the Alaskan Stream, sustaining high remineralization rates, with well-defined infaunal burrow structures in the sediment. Stations at the AT-A have a 2.5–24.1 cm thick, glacially derived fluid mud layer (FML) deprived of infauna, blanketing the original sediment surface. Chronological markers document that the infilling of the FML happened since the mid 1950′s and now extends to at least one fifth of the entire Aleutian Trench axis. The FML contains a mixture of fresh, marine-derived and recalcitrant terrigenous organics, with elevated microbial mineralization rates, presumably enhanced by microbial priming and efficient microbial degradation of otherwise recalcitrant organics. The AT-SS and SS have low TOC contents, exhibit very low microbial remineralization rates, with only sparse infaunal imprints. Our investigations document that the Aleutian Trench forms a unique hadal environment, while simultaneously confirming that hadal trenches generally act as depocenters with intensified microbial activity, sustained by various sources of organics.
{"title":"The benthic environment of the Aleutian Trench region: Sediment provenance, organic carbon sources and deposition dynamics","authors":"Marco B. Sindlev , John P. Balmonte , Frank Wenzhöfer , Wenjie Xiao , Peter Stief , Kazumasa Oguri , Masashi Tsuchiya , Yusuke Yokoyama , Arka Rudra , Donald E. Canfield , Hamed Sanei , Angelika Brandt , Ronnie N. Glud","doi":"10.1016/j.pocean.2025.103627","DOIUrl":"10.1016/j.pocean.2025.103627","url":null,"abstract":"<div><div>Sedimentological, mineralogical, chronological and basic biogeochemistry document that the Aleutian Trench region consists of four distinct regions, each with their respective benthic habitat, deposition dynamics, and material sourcing: the Northern Aleutian Slope (NS), Aleutian Trench – Axis (AT-A), Aleutian Trench – South Slope (AT-SS), and Southern Aleutian Slope (SS). The carbon pool is characterized by pyrolysis derived hydrogen and oxygen indices (HI and OI), radionuclides (Δ<sup>14</sup>C) and stable isotopes (δ<sup>13</sup>C-values), clearly varying among the respective regions. The NS has elevated total organic carbon (TOC) content, including distinct imprint of fresh, marine-derived organics originating from upwelling in the Gulf of Alaska with subsequent westward transport by the Alaskan Stream, sustaining high remineralization rates, with well-defined infaunal burrow structures in the sediment. Stations at the AT-A have a 2.5–24.1 cm thick, glacially derived fluid mud layer (FML) deprived of infauna, blanketing the original sediment surface. Chronological markers document that the infilling of the FML happened since the mid 1950′s and now extends to at least one fifth of the entire Aleutian Trench axis. The FML contains a mixture of fresh, marine-derived and recalcitrant terrigenous organics, with elevated microbial mineralization rates, presumably enhanced by microbial priming and efficient microbial degradation of otherwise recalcitrant organics. The AT-SS and SS have low TOC contents, exhibit very low microbial remineralization rates, with only sparse infaunal imprints. Our investigations document that the Aleutian Trench forms a unique hadal environment, while simultaneously confirming that hadal trenches generally act as depocenters with intensified microbial activity, sustained by various sources of organics.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103627"},"PeriodicalIF":3.6,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145598714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-25DOI: 10.1016/j.pocean.2025.103631
Sergio Neira , Hugo Arancibia , Mónica E. Barros , Ana Arriagada , Rubén Alarcón , Claudio Gatica
The Chilean Patagonia system (41°28.6′S–55° S) is influenced by the Cape Horn Current and exhibits high diversity, endemism, and important demersal stocks. However, food web structure and dynamics, the ecological role of key living components, and the impacts of fishing are poorly understood. In this paper, we model the structure and dynamics of the food web that sustains the demersal fish targeted by the fisheries operating in Chilean Patagonia, which takes place on the Patagonian Shelf and inshore waters. For this, we built a quantitative model for this ecosystem in 1980 using the Ecopath with Ecosim software, with 15 functional groups (from phytoplankton to top predators) including demersal target species such as hoki (Macruronus magellanicus), kingklip (Genypterus blacodes), southern blue whiting (Micromesistius australis), skates, and southern hake (Merluccius australis). We split hoki into juvenile and adult stanzas based on their importance as prey (juveniles) and landings (adults). Input data came from studies to estimate abundance, biomass, production, and diets of fishing target species and other key functional groups, while catch data came from official statistics. The model was balanced and fit to biomass and catch series from 1980 to 2020 using fishing mortality (F), vulnerability to predation parameters (v), and primary productivity anomaly (PP) estimated by model that aims to simulate PP trend. Zooplankton and benthos were the most important prey at intermediate trophic level consumers, while small pelagic fish and hoki juveniles were the main prey for higher trophic levels (i.e., hoki adults, southern hake, and southern blue whiting). Predation mortality (M2) of target species was salient and variable in time. The dynamics of fishing target species and the whole food web from 1980 to 2000 was explained mostly by fishing mortality, but model fit increased when considering PP and v. We conclude that i) juvenile hoki is a key prey group in the system, especially for hoki adults (cannibalism) and southern hake (predation), ii) southern hake is the main predator among demersal fish, and ii) fishing and bottom-up changes were important drivers in the system likely mediated by trophic interactions. These findings are crucial in moving forward on the development of ecosystem-based fisheries management in Chilean Patagonia.
智利巴塔哥尼亚系统（41°28.6 S - 55°S）受合恩角洋流影响，具有高度的多样性、特有性和重要的海底种群。然而，人们对食物网的结构和动态、关键生物成分的生态作用以及捕鱼的影响知之甚少。在本文中，我们模拟了在智利巴塔哥尼亚大陆架和近海水域作业的渔业中维持底栖鱼类的食物网的结构和动态。为此，我们于1980年使用Ecopath with Ecosim软件建立了该生态系统的定量模型，包括15个功能群（从浮游植物到顶级捕食者），包括底栖目标物种，如hoki (Macruronus magellanicus), kingklip (Genypterus blacodes), southern blue whitus australis (Micromesistius australis)， skates和southern hake （Merluccius australis）。我们根据它们作为猎物（幼鱼）和着陆物（成年鱼）的重要性将它们分为幼鱼和成年鱼。输入数据来自对捕捞目标物种和其他关键功能群的丰度、生物量、产量和饮食进行估计的研究，而捕捞数据来自官方统计。利用渔业死亡率(F)、捕食参数脆弱性(v)和初级生产力异常（PP）对1980 ~ 2020年的生物量和渔获量序列进行了平衡拟合。浮游动物和底栖动物是中等营养级食用者的主要猎物，而高营养级食用者的主要猎物是小远洋鱼类和白鱀豚幼鱼（白鱀豚成虫、南鳕和南蓝鳕）。靶种捕食死亡率（M2）具有显著性和时变性。1980 - 2000年的捕捞目标物种和整个食物网的动态变化主要以捕捞死亡率来解释，但当考虑PP和v时，模型拟合度增加。我们得出结论：1)幼鱼是系统中的关键猎物群体，特别是对河豚成鱼（食人）和南鳕（捕食）；2)南鳕是底栖鱼类中的主要捕食者；2)捕捞和自下而上的变化可能是营养相互作用的重要驱动因素。这些发现对于推动智利巴塔哥尼亚以生态系统为基础的渔业管理的发展至关重要。
{"title":"Analysing ecosystem and demersal stocks dynamics in the Chilean Patagonia system (41°28.6′S–57°S) from 1980 to 2020 using food web modelling","authors":"Sergio Neira , Hugo Arancibia , Mónica E. Barros , Ana Arriagada , Rubén Alarcón , Claudio Gatica","doi":"10.1016/j.pocean.2025.103631","DOIUrl":"10.1016/j.pocean.2025.103631","url":null,"abstract":"<div><div>The Chilean Patagonia system (41°28.6′S–55° S) is influenced by the Cape Horn Current and exhibits high diversity, endemism, and important demersal stocks. However, food web structure and dynamics, the ecological role of key living components, and the impacts of fishing are poorly understood. In this paper, we model the structure and dynamics of the food web that sustains the demersal fish targeted by the fisheries operating in Chilean Patagonia, which takes place on the Patagonian Shelf and inshore waters. For this, we built a quantitative model for this ecosystem in 1980 using the Ecopath with Ecosim software, with 15 functional groups (from phytoplankton to top predators) including demersal target species such as hoki (<em>Macruronus magellanicus</em>), kingklip (<em>Genypterus blacodes</em>), southern blue whiting (<em>Micromesistius australis</em>), skates, and southern hake (<em>Merluccius australis</em>). We split hoki into juvenile and adult stanzas based on their importance as prey (juveniles) and landings (adults). Input data came from studies to estimate abundance, biomass, production, and diets of fishing target species and other key functional groups, while catch data came from official statistics. The model was balanced and fit to biomass and catch series from 1980 to 2020 using fishing mortality (F), vulnerability to predation parameters (v), and primary productivity anomaly (PP) estimated by model that aims to simulate PP trend. Zooplankton and benthos were the most important prey at intermediate trophic level consumers, while small pelagic fish and hoki juveniles were the main prey for higher trophic levels (i.e., hoki adults, southern hake, and southern blue whiting). Predation mortality (M2) of target species was salient and variable in time. The dynamics of fishing target species and the whole food web from 1980 to 2000 was explained mostly by fishing mortality, but model fit increased when considering PP and v. We conclude that i) juvenile hoki is a key prey group in the system, especially for hoki adults (cannibalism) and southern hake (predation), ii) southern hake is the main predator among demersal fish, and ii) fishing and bottom-up changes were important drivers in the system likely mediated by trophic interactions. These findings are crucial in moving forward on the development of ecosystem-based fisheries management in Chilean Patagonia.</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103631"},"PeriodicalIF":3.6,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145598716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-24DOI: 10.1016/j.pocean.2025.103629
Luísa M. Garcia , Iole Beatriz M. Orselli , Virginia Maria Tavano , Carlos Rafael B. Mendes , Carlos Alberto E. Garcia , Rosane G. Ito , Catherine Goyet , Rodrigo Kerr
Considering that oxygen (O2) and carbon dioxide (CO2) are subject to many of the same biological and physical drivers, a combined investigation of these gases provides a comprehensive framework to elucidate the mechanisms that govern their sea-air exchanges. To investigate these controls on the Patagonian shelf, we analysed temperature, salinity, dissolved O2, and continuous CO2 measurements from springs of 2004, and 2006–2008, and summers of 2007, 2008 and 2009. Phytoplankton biomass was classified by pigment composition via high-performance liquid chromatography and microscopic counts. The findings suggest that in the northern shelf (36°–40°S), despite low phytoplankton biomass (mainly haptophytes, 45 %), photosynthesis modulated fluxes, leading to O2 outgassing (14 ± 9 mmol m−2 d−1) and CO2 uptake (–4 ± 3 mmol m−2 d−1). Between 40°–51°S, spring diatom blooms (82 % diatom and up to 22.5 mg m-3 Chl–a) were correlated with the highest O2 outgassing (91 mmol m−2 d−1) and CO2 uptake (–40 mmol m−2 d−1), driven by the photosynthesis. In contrast, around 50°S, summer fluxes were associated with a predominance of net respiration, thermal processes, and the advection of O2-undersaturated waters, resulting in an O2and CO2 uptake (–41 ± 7 mmol m−2 d−1 and –9 ± 4 mmol m−2 d−1, respectively). South of 52°S, summer conditions shifted the region from a CO2 sink to a source due to warming and lower phytoplankton biomass (0.6 ± 0.5 mg m−3).
考虑到氧气（O2）和二氧化碳（CO2）受到许多相同的生物和物理驱动因素的影响，对这些气体的综合研究提供了一个全面的框架来阐明控制它们的海气交换的机制。为了调查巴塔哥尼亚大陆架上的这些控制因素，我们分析了2004年春季、2006-2008年春季以及2007年、2008年和2009年夏季的温度、盐度、溶解氧和连续的二氧化碳测量值。通过高效液相色谱法和显微计数法对浮游植物生物量进行了分类。研究结果表明，在北大陆架（36°-40°S），尽管浮游植物生物量较低（主要是共生植物，45%），但光合作用调节了通量，导致O2释放（14±9 mmol m−2 d−1）和CO2吸收（-4±3 mmol m−2 d−1）。在40°-51°S之间，春季硅藻华（82%硅藻和高达22.5 mg m-3 Chl-a）与光合作用驱动的最高O2放出（91 mmol m- 2 d - 1）和CO2吸收（-40 mmol m- 2 d - 1）相关。相反，在50°S左右，夏季通量与净呼吸、热过程和o2不饱和水平流的优势相关，导致o2和CO2的吸收（分别为-41±7 mmol m - 2 d - 1和-9±4 mmol m - 2 d - 1）。在52°S以南，由于变暖和较低的浮游植物生物量（0.6±0.5 mg m - 3），夏季条件使该地区从CO2汇转变为CO2源。
{"title":"Controls of sea–air O2 and CO2 exchanges along the Patagonian shelf-break: the role of temperature and phytoplankton communities","authors":"Luísa M. Garcia , Iole Beatriz M. Orselli , Virginia Maria Tavano , Carlos Rafael B. Mendes , Carlos Alberto E. Garcia , Rosane G. Ito , Catherine Goyet , Rodrigo Kerr","doi":"10.1016/j.pocean.2025.103629","DOIUrl":"10.1016/j.pocean.2025.103629","url":null,"abstract":"<div><div>Considering that oxygen (O<sub>2</sub>) and carbon dioxide (CO<sub>2</sub>) are subject to many of the same biological and physical drivers, a combined investigation of these gases provides a comprehensive framework to elucidate the mechanisms that govern their sea-air exchanges. To investigate these controls on the Patagonian shelf, we analysed temperature, salinity, dissolved O<sub>2</sub>, and continuous CO<sub>2</sub> measurements from springs of 2004, and 2006–2008, and summers of 2007, 2008 and 2009. Phytoplankton biomass was classified by pigment composition via high-performance liquid chromatography and microscopic counts. The findings suggest that in the northern shelf (36°–40°S), despite low phytoplankton biomass (mainly haptophytes, 45 %), photosynthesis modulated fluxes, leading to O<sub>2</sub> outgassing (14 ± 9 mmol m<sup>−</sup><sup>2</sup> d<sup>−</sup><sup>1</sup>) and CO<sub>2</sub> uptake (–4 ± 3 mmol m<sup>−</sup><sup>2</sup> d<sup>−</sup><sup>1</sup>). Between 40°–51°S, spring diatom blooms (82 % diatom and up to 22.5 mg m<sup>-3</sup> Chl–<em>a</em>) were correlated with the highest O<sub>2</sub> outgassing (91 mmol m<sup>−</sup><sup>2</sup> d<sup>−</sup><sup>1</sup>) and CO<sub>2</sub> uptake (–40 mmol m<sup>−</sup><sup>2</sup> d<sup>−</sup><sup>1</sup>), driven by the photosynthesis. In contrast, around 50°S, summer fluxes were associated with a predominance of net respiration, thermal processes, and the advection of O<sub>2</sub>-undersaturated waters, resulting in an O<sub>2</sub>and CO<sub>2</sub> uptake (–41 ± 7 mmol m<sup>−2</sup> d<sup>−1</sup> and –9 ± 4 mmol m<sup>−</sup><sup>2</sup> d<sup>−</sup><sup>1</sup>, respectively). South of 52°S, summer conditions shifted the region from a CO<sub>2</sub> sink to a source due to warming and lower phytoplankton biomass (0.6 ± 0.5 mg m<sup>−</sup><sup>3</sup>).</div></div>","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"241 ","pages":"Article 103629"},"PeriodicalIF":3.6,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145583774","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}
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":"2025-11-23","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}
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