Pub Date : 2025-12-01Epub Date: 2025-10-30DOI: 10.1016/j.dsr2.2025.105557
Criado Léa , Barboni Alexandre , Carton Xavier
The PHYSINDIEN 2019 campaign occurred in the Northwestern Arabian Sea, during the spring intermonsoon, between 16 and 25 °N. Along its 3000 km transect, it sampled 5 anticyclones, 3 cyclones and 2 cyclonic submesoscale coherent vortices (SCV) with continuous hydrological and velocity measurements. Remarkably, the two cyclonic SCV were located beneath surface mesoscale anticyclones. Also, a water mass analysis shows that small anticyclones with Persian Gulf Water (PGW) are found in the Gulf of Oman, while anticyclones further south are shallower vortices containing Arabian Sea High Salinity Water (ASHSW). Comparison of in situ data with the META atlas, a state-of-the-art eddy detection and tracking atlas based on altimetry, reveals that eddy radii are often underestimated by remote sensing. In this atlas, eddy tracks are often discontinuous due to missing detections. Both hydrological measurements and remote-sensing tracking are however consistent in indicating that along the southern Omani coast anticyclones are formed offshore during the spring intermonsoon, near the center of the Arabian Sea. These results underline the diversity of surface and subsurface eddies in the sparsely explored Arabian Sea, and provide insight on the potential bias of their remote detections.
{"title":"Mesoscale processes in the northern Arabian Sea: Linking in situ observations to remote-sensing","authors":"Criado Léa , Barboni Alexandre , Carton Xavier","doi":"10.1016/j.dsr2.2025.105557","DOIUrl":"10.1016/j.dsr2.2025.105557","url":null,"abstract":"<div><div>The PHYSINDIEN 2019 campaign occurred in the Northwestern Arabian Sea, during the spring intermonsoon, between 16 and 25 °N. Along its 3000 km transect, it sampled 5 anticyclones, 3 cyclones and 2 cyclonic submesoscale coherent vortices (SCV) with continuous hydrological and velocity measurements. Remarkably, the two cyclonic SCV were located beneath surface mesoscale anticyclones. Also, a water mass analysis shows that small anticyclones with Persian Gulf Water (PGW) are found in the Gulf of Oman, while anticyclones further south are shallower vortices containing Arabian Sea High Salinity Water (ASHSW). Comparison of in situ data with the META atlas, a state-of-the-art eddy detection and tracking atlas based on altimetry, reveals that eddy radii are often underestimated by remote sensing. In this atlas, eddy tracks are often discontinuous due to missing detections. Both hydrological measurements and remote-sensing tracking are however consistent in indicating that along the southern Omani coast anticyclones are formed offshore during the spring intermonsoon, near the center of the Arabian Sea. These results underline the diversity of surface and subsurface eddies in the sparsely explored Arabian Sea, and provide insight on the potential bias of their remote detections.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105557"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462846","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 : 2025-12-01Epub Date: 2025-11-01DOI: 10.1016/j.dsr2.2025.105558
Candice N. Cooper , Christopher A. Edwards , John L. Largier , Piero L.F. Mazzini
A descriptive analysis of remotely-sensed surface chlorophyll-a within the Gulf of the Farallones and nearby coastal waters occupying portions of three NOAA National Marine Sanctuaries along the central California coast is presented. The seasonal cycle from a 25-year chlorophyll-a record reveals elevated levels near the mouth of San Francisco Bay at the Golden Gate, with broad spatial extent climatologically from April through November. A 19-year time series of normalized water-leaving radiance at the 555 nm band (nLw555) was used to estimate the presence of waters representing the San Francisco Bay plume. Although the plume shows its largest spatial extent in winter, decreasing during spring and summer, chlorophyll-a was enhanced within plume waters relative to non-plume waters during all months; however, was not statistically different during upwelling months (April–June). Linear correlations between chlorophyll-a and a 20-year record of wind stress, a 10-year record of surface currents, and a 20-year record of sea surface temperatures reveal consistent, coherent regional spatial patterns. Weighted averages confirm that poleward winds and surface currents result in enhanced chlorophyll-a in nearshore waters north of the Golden Gate and around Point Reyes. Periods of equatorward winds and surface transport exhibit elevated chlorophyll-a and temperature south of the Golden Gate, offshore of Half Moon Bay, and are associated with nearby onshore currents. Correlations of plume concentrations (nLw555 W m−2 m−1 sr−1) with wind stress, however, do not show the same coherent patterns as with chlorophyll-a, and turbid plume waters are largely confined to the Gulf of the Farallones. These analyses suggest that surface chlorophyll-a within the inner Gulf of the Farallones close to San Francisco Bay is significantly influenced by outflow from the Bay, but the greater Gulf of Farallones is more strongly influenced by upwelling and relaxation effects.
本文对法拉隆湾和位于加州中部海岸的三个NOAA国家海洋保护区附近的沿海水域的遥感地表叶绿素- A进行了描述性分析。从25年的叶绿素记录的季节周期来看，在金门湾的旧金山湾口附近，从4月到11月，在气候上具有广泛的空间范围，叶绿素水平升高。在555nm波段（nLw555）的19年标准化水离开辐射时间序列被用来估计代表旧金山湾羽流的水的存在。尽管羽流的空间范围在冬季最大，在春夏两季逐渐减小，但在所有月份中，羽流水体内的叶绿素a均比非羽流水体增强；而在上升流月份（4 - 6月），差异无统计学意义。叶绿素-a与20年风应力记录、10年地表洋流记录和20年海面温度记录之间的线性相关揭示了一致的、连贯的区域空间格局。加权平均值证实，在金门以北和雷耶斯角附近的近岸水域，向极地方向的风和表面洋流导致叶绿素-a的增加。在金门以南，半月湾近海，赤道风和地面运输的时期，叶绿素-a和温度升高，并与附近的陆上洋流有关。然而，羽流浓度（nLw555≥12 W m−2 μm−1 sr−1）与风应力的相关性与叶绿素-a的相关性不一致，并且浑浊的羽流水主要局限于Farallones湾。这些分析表明，在靠近旧金山湾的Farallones内湾，表层叶绿素-a受到海湾流出物的显著影响，但Farallones大湾受上升流和松弛效应的影响更为强烈。
{"title":"Interaction of bay outflow and wind-driven upwelling in chlorophyll patterns in the Gulf of the Farallones","authors":"Candice N. Cooper , Christopher A. Edwards , John L. Largier , Piero L.F. Mazzini","doi":"10.1016/j.dsr2.2025.105558","DOIUrl":"10.1016/j.dsr2.2025.105558","url":null,"abstract":"<div><div>A descriptive analysis of remotely-sensed surface chlorophyll-<em>a</em> within the Gulf of the Farallones and nearby coastal waters occupying portions of three NOAA National Marine Sanctuaries along the central California coast is presented. The seasonal cycle from a 25-year chlorophyll-<em>a</em> record reveals elevated levels near the mouth of San Francisco Bay at the Golden Gate, with broad spatial extent climatologically from April through November. A 19-year time series of normalized water-leaving radiance at the 555 nm band (nLw555) was used to estimate the presence of waters representing the San Francisco Bay plume. Although the plume shows its largest spatial extent in winter, decreasing during spring and summer, chlorophyll-<em>a</em> was enhanced within plume waters relative to non-plume waters during all months; however, was not statistically different during upwelling months (April–June). Linear correlations between chlorophyll-<em>a</em> and a 20-year record of wind stress, a 10-year record of surface currents, and a 20-year record of sea surface temperatures reveal consistent, coherent regional spatial patterns. Weighted averages confirm that poleward winds and surface currents result in enhanced chlorophyll-<em>a</em> in nearshore waters north of the Golden Gate and around Point Reyes. Periods of equatorward winds and surface transport exhibit elevated chlorophyll-<em>a</em> and temperature south of the Golden Gate, offshore of Half Moon Bay, and are associated with nearby onshore currents. Correlations of plume concentrations (nLw555 <span><math><mrow><mo>≥</mo><mspace></mspace><mn>12</mn></mrow></math></span> W m<sup>−2</sup> <span><math><mi>μ</mi></math></span>m<sup>−1</sup> sr<sup>−1</sup>) with wind stress, however, do not show the same coherent patterns as with chlorophyll-<em>a</em>, and turbid plume waters are largely confined to the Gulf of the Farallones. These analyses suggest that surface chlorophyll-<em>a</em> within the inner Gulf of the Farallones close to San Francisco Bay is significantly influenced by outflow from the Bay, but the greater Gulf of Farallones is more strongly influenced by upwelling and relaxation effects.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105558"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The 2022 Indian Ocean Expedition organised by Monaco Explorations rolled out an ambitious outreach and communication strategy to raise awareness among a wide range of audiences about critical ocean issues and share the expedition outcomes with various target groups: the media, the general public, decision-makers and civil society stakeholders, teachers, the young generation, etc. This article provides an in-depth critical analysis of the objectives, design, and implementation of outreach mechanisms and the results achieved, using quantitative and qualitative indicators to highlight successes, limitations, and challenges, particularly in terms of assessing the results and the ownership of issues. In conclusion, a number of avenues are proposed to amplify and optimise the impact of such outreach and communication activities and their contribution to the Ocean Literacy approach, particularly in the context of the United Nations Decade of Ocean Science for Sustainable Development (2021–2030).
{"title":"Awareness-raising, communication methods and objectives for an ocean expedition: the example of the Monaco explorations Indian Ocean expedition 2022","authors":"Didier Théron , Océane Gasquy , François Simard , Dominique Benzaken , Elise Rigot , Amwar Bhai Rumjaun , Stéphane Dugast , Rémi Leroy , Carolyn Scheurle","doi":"10.1016/j.dsr2.2025.105551","DOIUrl":"10.1016/j.dsr2.2025.105551","url":null,"abstract":"<div><div>The 2022 Indian Ocean Expedition organised by Monaco Explorations rolled out an ambitious outreach and communication strategy to raise awareness among a wide range of audiences about critical ocean issues and share the expedition outcomes with various target groups: the media, the general public, decision-makers and civil society stakeholders, teachers, the young generation, etc. This article provides an in-depth critical analysis of the objectives, design, and implementation of outreach mechanisms and the results achieved, using quantitative and qualitative indicators to highlight successes, limitations, and challenges, particularly in terms of assessing the results and the ownership of issues. In conclusion, a number of avenues are proposed to amplify and optimise the impact of such outreach and communication activities and their contribution to the Ocean Literacy approach, particularly in the context of the United Nations Decade of Ocean Science for Sustainable Development (2021–2030).</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105551"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145412759","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 : 2025-12-01Epub Date: 2025-10-14DOI: 10.1016/j.dsr2.2025.105553
Paola Galloso , Giancarlo M. Correa , Pierre Legendre
The northern Humboldt Current System (HCS) is a highly productive eastern boundary upwelling system off Peru. El Niño Southern Oscillation (ENSO) is one of the main drivers of short-term climate variability, whose warm (El Niño) and cold (La Niña) phases can trigger changes in the physical, chemical, biological, and socioeconomic conditions of the northern HCS. We explored the impacts of ENSO phases and magnitude in the region over the structure of the pelagic fish community in the northern HCS through the study of spatial and temporal beta diversity changes. To achieve this goal, we used 25-year taxonomic composition data from pelagic scientific surveys and statistical multivariate methods. We found that, depending on the magnitudes, most of the El Niño (EN) categories substantially increased the diversity index values in this system with respect to the neutral phase. In contrast, La Niña (LN) decreased it. The community spatial structure principally showed three ecological regions, which varied in extension, indicator species, and composition across ENSO phases. The local contribution to beta diversity (LCBD) showed that the shelf break is essential in shaping the community structure among ENSO phases. The changes in temporal beta diversity suggest that the spatial structure or change of the community abundance is influenced by the magnitude of the EN phase. We conclude that the oceanographic changes caused by the ENSO phases may significantly impact the fish community structure in the northern HCS. Our results are relevant to implementing climate-ready management measures in this ecosystem.
{"title":"The impacts of El Niño Southern Oscillation on the pelagic fish community structure of the northern Humboldt Current system","authors":"Paola Galloso , Giancarlo M. Correa , Pierre Legendre","doi":"10.1016/j.dsr2.2025.105553","DOIUrl":"10.1016/j.dsr2.2025.105553","url":null,"abstract":"<div><div>The northern Humboldt Current System (HCS) is a highly productive eastern boundary upwelling system off Peru. El Niño Southern Oscillation (ENSO) is one of the main drivers of short-term climate variability, whose warm (El Niño) and cold (La Niña) phases can trigger changes in the physical, chemical, biological, and socioeconomic conditions of the northern HCS. We explored the impacts of ENSO phases and magnitude in the region over the structure of the pelagic fish community in the northern HCS through the study of spatial and temporal beta diversity changes. To achieve this goal, we used 25-year taxonomic composition data from pelagic scientific surveys and statistical multivariate methods. We found that, depending on the magnitudes, most of the El Niño (EN) categories substantially increased the diversity index values in this system with respect to the neutral phase. In contrast, La Niña (LN) decreased it. The community spatial structure principally showed three ecological regions, which varied in extension, indicator species, and composition across ENSO phases. The local contribution to beta diversity (LCBD) showed that the shelf break is essential in shaping the community structure among ENSO phases. The changes in temporal beta diversity suggest that the spatial structure or change of the community abundance is influenced by the magnitude of the EN phase. We conclude that the oceanographic changes caused by the ENSO phases may significantly impact the fish community structure in the northern HCS. Our results are relevant to implementing climate-ready management measures in this ecosystem.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105553"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324366","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 : 2025-12-01Epub Date: 2025-10-16DOI: 10.1016/j.dsr2.2025.105552
Saskia Brix , Thea Sophie Elsig , Patricia Esquete , Áki Jarl Láruson , Katrin Linse , Elisabeth Schaal , Lydia Anastasia Schmidt , Carolin Uhlir , Johanna N.J. Weston , Anne-Nina Lörz
Amathillopsis spinigera Heller, 1875, is an enigmatic peracarid crustacean species found in the Arctic Ocean. During the summer of 2024, it was recorded in the HAUSGARTEN observatory for the first time, following 25 years of regular sampling as part of the Fram Strait Long-Term Ecological Research observatory. This study significantly broadens the known geographic and bathymetric range of A. spinigera, with a total of 46 specimens collected from HAUSGARTEN (HG) and cold seeps at Svyatogor Ridge, during two expeditions conducted in 2024. Further, our review of all publicly available database (historical) records for A. spinigera leads to an expansion of its depth range from 186 – 1972 m to 11 – 3182 m. Recent observations using remotely operated vehicles (ROVs) have confirmed their clinging behavior on organic structures such as worm tubes, likely elevating the species within the water column to facilitate food capture. Females at various life stages, including egg-bearing individuals, were observed alongside juveniles and males of different sizes, enabling a redescription of the species based on an integrative taxonomy approach that incorporates both molecular and morphological data. The study also highlights biogeographic patterns, with a notable preference for eastern occurrences along the Arctic continental slope. While gaps in data from Greenland and Canadian regions, coupled with minimal sampling in the Central Arctic Ocean, suggest potential sampling bias, circumarctic connectivity appears plausible. This inference is supported by high genetic similarity in barcode data from individuals found across distant geographic locations.
{"title":"Clinging onto Arctic Benthos: Biogeography of Amathillopsis spinigera Heller, 1875 (Crustacea: Amphipoda), including its redescription","authors":"Saskia Brix , Thea Sophie Elsig , Patricia Esquete , Áki Jarl Láruson , Katrin Linse , Elisabeth Schaal , Lydia Anastasia Schmidt , Carolin Uhlir , Johanna N.J. Weston , Anne-Nina Lörz","doi":"10.1016/j.dsr2.2025.105552","DOIUrl":"10.1016/j.dsr2.2025.105552","url":null,"abstract":"<div><div><em>Amathillopsis spinigera</em> Heller, 1875, is an enigmatic peracarid crustacean species found in the Arctic Ocean. During the summer of 2024, it was recorded in the HAUSGARTEN observatory for the first time, following 25 years of regular sampling as part of the Fram Strait Long-Term Ecological Research observatory. This study significantly broadens the known geographic and bathymetric range of <em>A. spinigera</em>, with a total of 46 specimens collected from HAUSGARTEN (HG) and cold seeps at Svyatogor Ridge, during two expeditions conducted in 2024. Further, our review of all publicly available database (historical) records for <em>A. spinigera</em> leads to an expansion of its depth range from 186 – 1972 m to 11 – 3182 m. Recent observations using remotely operated vehicles (ROVs) have confirmed their clinging behavior on organic structures such as worm tubes, likely elevating the species within the water column to facilitate food capture. Females at various life stages, including egg-bearing individuals, were observed alongside juveniles and males of different sizes, enabling a redescription of the species based on an integrative taxonomy approach that incorporates both molecular and morphological data. The study also highlights biogeographic patterns, with a notable preference for eastern occurrences along the Arctic continental slope. While gaps in data from Greenland and Canadian regions, coupled with minimal sampling in the Central Arctic Ocean, suggest potential sampling bias, circumarctic connectivity appears plausible. This inference is supported by high genetic similarity in barcode data from individuals found across distant geographic locations.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105552"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525779","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 : 2025-12-01Epub Date: 2025-09-29DOI: 10.1016/j.dsr2.2025.105550
Fatemeh Shabani , Mohammad Raie , Keivan Kabiri
Coral reefs are among the most biodiverse marine ecosystems but are increasingly threatened by environmental stressors, particularly coral bleaching caused by rising Sea Surface Temperature (SST). Monitoring SST changes is therefore critical for coral conservation. This study investigates thermal anomalies around Kish Island in the northern Persian Gulf using the Degree Heating Weeks (DHW) index, which quantifies cumulative thermal stress on corals. SST and DHW data from 1982 to 2022 were obtained from the National Oceanic and Atmospheric Administration (NOAA). Trends were analyzed using the Mann-Kendall test and Sen's slope estimator, while the Pierce Skill Score was employed to estimate the DHW threshold indicating coral bleaching risk. The relationship between the El Niño phenomenon and DHW was also assessed. Spatial and temporal SST changes were examined using MODIS Aqua satellite data processed via the Google Earth Engine. Results show maximum SST and DHW values of 35.17 °C and 13.6°C-weeks in August–September 2017, respectively, with DHW exhibiting an upward trend of 0.025°C-weeks per year. The DHW threshold was estimated at 5.3°C-weeks. Spatial analyses suggest increasing thermal stress along the southern and northern coasts of the Persian Gulf, particularly near Kish Island. Finally, El Niño events corresponded with elevated DHW values, highlighting their influence on coral bleaching. These findings underscore the importance of long-term monitoring to mitigate climate-induced threats to coral ecosystems.
{"title":"Studying the impact of sea surface temperature (SST) changes and El Niño phenomenon on coral reefs bleaching around Kish Island in the northern Persian Gulf: A remote sensing approach","authors":"Fatemeh Shabani , Mohammad Raie , Keivan Kabiri","doi":"10.1016/j.dsr2.2025.105550","DOIUrl":"10.1016/j.dsr2.2025.105550","url":null,"abstract":"<div><div>Coral reefs are among the most biodiverse marine ecosystems but are increasingly threatened by environmental stressors, particularly coral bleaching caused by rising Sea Surface Temperature (SST). Monitoring SST changes is therefore critical for coral conservation. This study investigates thermal anomalies around Kish Island in the northern Persian Gulf using the Degree Heating Weeks (DHW) index, which quantifies cumulative thermal stress on corals. SST and DHW data from 1982 to 2022 were obtained from the National Oceanic and Atmospheric Administration (NOAA). Trends were analyzed using the Mann-Kendall test and Sen's slope estimator, while the Pierce Skill Score was employed to estimate the DHW threshold indicating coral bleaching risk. The relationship between the El Niño phenomenon and DHW was also assessed. Spatial and temporal SST changes were examined using MODIS Aqua satellite data processed via the Google Earth Engine. Results show maximum SST and DHW values of 35.17 °C and 13.6°C-weeks in August–September 2017, respectively, with DHW exhibiting an upward trend of 0.025°C-weeks per year. The DHW threshold was estimated at 5.3°C-weeks. Spatial analyses suggest increasing thermal stress along the southern and northern coasts of the Persian Gulf, particularly near Kish Island. Finally, El Niño events corresponded with elevated DHW values, highlighting their influence on coral bleaching. These findings underscore the importance of long-term monitoring to mitigate climate-induced threats to coral ecosystems.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105550"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263170","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 : 2025-12-01Epub Date: 2025-09-11DOI: 10.1016/j.dsr2.2025.105546
Nissa Kreidler , Andre Buchheister , David D. Huff , Jerome Fiechter , Mary Yoklavich , Mark J. Henderson
Deep-sea corals and sponges (DSCS) are signature taxa of deep-water habitats, but ecological mechanisms that drive their geographic distributions can be difficult to uncover due to the challenges of surveying deep-water ecosystems and limited oceanographic data. A comparison of species distribution models was made for three DSCS (Antipathes dendochristos, Plumarella longispina, and an unidentified sponge morphotype known as Porifera #2), two of which are associated with young-of-the-year and adult rockfish taxa (Sebastes spp.). Models were built using generalized additive models (GAMs) that accounted for spatial autocorrelation. These models were compared to Maxent models, a commonly used method. All models utilized bathymetrically derived variables (including depth, slope, and Bathymetric Position Index) and output from a coupled physical-biogeochemical ocean model (including current direction and magnitude, food abundance, and dissolved oxygen). Direction of benthic ocean currents played an important role in predictions, pointing to large-scale ecological processes that may determine presence of DSCS. GAMs outperformed Maxent models and predicted more ecologically interpretable patterns. Additionally we quantified the predicted amount of suitable habitat that is currently located within some protected areas of the Southern California Bight and show that many hot spots occur outside protected areas. Given the importance of DSCS for multiple demersal fish species of commercial or conservation concerns, this research provides valuable information that natural resource managers can use as a tool in the Southern California Bight.
{"title":"A comparison of deep-sea coral and sponge species distribution models and the impact of ocean currents in the Southern California Bight","authors":"Nissa Kreidler , Andre Buchheister , David D. Huff , Jerome Fiechter , Mary Yoklavich , Mark J. Henderson","doi":"10.1016/j.dsr2.2025.105546","DOIUrl":"10.1016/j.dsr2.2025.105546","url":null,"abstract":"<div><div>Deep-sea corals and sponges (DSCS) are signature taxa of deep-water habitats, but ecological mechanisms that drive their geographic distributions can be difficult to uncover due to the challenges of surveying deep-water ecosystems and limited oceanographic data. A comparison of species distribution models was made for three DSCS (<em>Antipathes dendochristos, Plumarella longispina,</em> and an unidentified sponge morphotype known as Porifera #2), two of which are associated with young-of-the-year and adult rockfish taxa (<em>Sebastes</em> spp.). Models were built using generalized additive models (GAMs) that accounted for spatial autocorrelation. These models were compared to Maxent models, a commonly used method. All models utilized bathymetrically derived variables (including depth, slope, and Bathymetric Position Index) and output from a coupled physical-biogeochemical ocean model (including current direction and magnitude, food abundance, and dissolved oxygen). Direction of benthic ocean currents played an important role in predictions, pointing to large-scale ecological processes that may determine presence of DSCS. GAMs outperformed Maxent models and predicted more ecologically interpretable patterns. Additionally we quantified the predicted amount of suitable habitat that is currently located within some protected areas of the Southern California Bight and show that many hot spots occur outside protected areas. Given the importance of DSCS for multiple demersal fish species of commercial or conservation concerns, this research provides valuable information that natural resource managers can use as a tool in the Southern California Bight.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"224 ","pages":"Article 105546"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358869","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 : 2025-09-01Epub Date: 2025-07-29DOI: 10.1016/j.dsr2.2025.105522
Antonia U. Thielecke , Mar Fernández-Méndez , Javier Arístegui , Moritz Baumann , Jacqueline Behncke , Stella A. Berger , Veit Dausmann , Silvia Georgieva , Silvan U. Goldenberg , Gonzalo V. Gomez-Saez , Michelle Graco , Toralf Heene , Leila Richards Kittu , Jeffrey W. Krause , Andrea Ludwig , Jana Meyer , Volker Mohrholz , Jens C. Nejstgaard , Joaquin Ortiz-Cortes , Kai G. Schulz , Ulf Riebesell
The Humboldt upwelling system (HUS) is known for its extraordinary productivity due to wind-driven upwelling of nutrient-rich deep water, resulting in the highest fish catches per unit area worldwide. However, contrary to other Eastern boundary upwelling systems, upwelling intensity is highest in winter, while primary productivity reaches its peak during the summer months. Our current understanding of the counterintuitive relationship between upwelling intensity and productivity is insufficient to predict the consequences of climate change on this ecosystem. To elucidate the drivers of the upwelling-productivity relationship in the HUS, we tested the hypothesis that low light availability limits primary productivity in winter despite strong upwelling intensity supplying plenty of nutrients into the surface layer, while light availability in the shallower mixed layer in summer enables an effective use of the upwelled nutrients. To disentangle the interactive effects of light and nutrients on primary production and carbon cycling, we enclosed natural plankton communities off the coast of Callao (Peru) during a 35-day mesocosm experiment by recreating summer-time high light and winter-time low light conditions under different upwelling intensities (0 %, 15 %, 30 %, 45 % and 60 %). Primary productivity and phytoplankton biomass scaled with both nitrate and light availability. Comparing the same upwelling intensity at different light levels, our data confirmed the hypothesis that light limitation due to deepening of the mixed layer is a key driver for the out-of-phase observations in primary productivity in the Humboldt upwelling system. Under light limiting conditions phytoplankton had low POC:Chla ratios indicating photoacclimation and low POC:PON ratios indicating light limitation of nitrate uptake which leads to increased food quality for grazers in winter. Our study indicates that small seasonal changes in phytoplankton biomass (estimated using Chla) might hide larger changes in primary productivity (carbon uptake), and highlights the importance of combining satellite studies with in situ observations and experimental studies to predict the fate of upwelling systems in a changing ocean. Increased stratification caused by global warming in upwelling systems such as the HUS would lead to less phytoplankton biomass with higher POC:Chla and POC:PON ratios. This phytoplankton community would have lower food quality for grazers and might lead to a decline in the transfer to higher trophic levels, but at the same time might lead to increased CO2 drawdown in an otherwise CO2 emitting ecosystem. Understanding the unique relationship between upwelling intensity and productivity in the HUS contributes to predicting the reaction of this valuable ecosystem for fisheries to the impacts of climate change.
{"title":"Disentangling upwelling: how light and nutrient supply shape primary producers and stoichiometry in the Humboldt upwelling system","authors":"Antonia U. Thielecke , Mar Fernández-Méndez , Javier Arístegui , Moritz Baumann , Jacqueline Behncke , Stella A. Berger , Veit Dausmann , Silvia Georgieva , Silvan U. Goldenberg , Gonzalo V. Gomez-Saez , Michelle Graco , Toralf Heene , Leila Richards Kittu , Jeffrey W. Krause , Andrea Ludwig , Jana Meyer , Volker Mohrholz , Jens C. Nejstgaard , Joaquin Ortiz-Cortes , Kai G. Schulz , Ulf Riebesell","doi":"10.1016/j.dsr2.2025.105522","DOIUrl":"10.1016/j.dsr2.2025.105522","url":null,"abstract":"<div><div>The Humboldt upwelling system (HUS) is known for its extraordinary productivity due to wind-driven upwelling of nutrient-rich deep water, resulting in the highest fish catches per unit area worldwide. However, contrary to other Eastern boundary upwelling systems, upwelling intensity is highest in winter, while primary productivity reaches its peak during the summer months. Our current understanding of the counterintuitive relationship between upwelling intensity and productivity is insufficient to predict the consequences of climate change on this ecosystem. To elucidate the drivers of the upwelling-productivity relationship in the HUS, we tested the hypothesis that low light availability limits primary productivity in winter despite strong upwelling intensity supplying plenty of nutrients into the surface layer, while light availability in the shallower mixed layer in summer enables an effective use of the upwelled nutrients. To disentangle the interactive effects of light and nutrients on primary production and carbon cycling, we enclosed natural plankton communities off the coast of Callao (Peru) during a 35-day mesocosm experiment by recreating summer-time high light and winter-time low light conditions under different upwelling intensities (0 %, 15 %, 30 %, 45 % and 60 %). Primary productivity and phytoplankton biomass scaled with both nitrate and light availability. Comparing the same upwelling intensity at different light levels, our data confirmed the hypothesis that light limitation due to deepening of the mixed layer is a key driver for the out-of-phase observations in primary productivity in the Humboldt upwelling system. Under light limiting conditions phytoplankton had low POC:Chl<em>a</em> ratios indicating photoacclimation and low POC:PON ratios indicating light limitation of nitrate uptake which leads to increased food quality for grazers in winter. Our study indicates that small seasonal changes in phytoplankton biomass (estimated using Chl<em>a</em>) might hide larger changes in primary productivity (carbon uptake), and highlights the importance of combining satellite studies with in situ observations and experimental studies to predict the fate of upwelling systems in a changing ocean. Increased stratification caused by global warming in upwelling systems such as the HUS would lead to less phytoplankton biomass with higher POC:Chl<em>a</em> and POC:PON ratios. This phytoplankton community would have lower food quality for grazers and might lead to a decline in the transfer to higher trophic levels, but at the same time might lead to increased CO<sub>2</sub> drawdown in an otherwise CO<sub>2</sub> emitting ecosystem. Understanding the unique relationship between upwelling intensity and productivity in the HUS contributes to predicting the reaction of this valuable ecosystem for fisheries to the impacts of climate change.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"223 ","pages":"Article 105522"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144771646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Persian Gulf is a shallow, semi-enclosed marginal sea basin characterized by a distinct geological history, harsh environmental conditions, and intermittent connection with the Indian Ocean during the Pleistocene glacial periods. Brachyuran crabs constitute a diverse component of the Persian Gulf fauna, distributed unevenly in the various habitats. The biodiversity and regional biogeographic data for the Persian Gulf and Gulf of Oman crab fauna are still poorly understood and rarely incorporated into global biodiversity databases. Here, we have addressed this shortfall by mapping the regional distributions of 262 species of brachyuran crabs in the Persian Gulf and the Gulf of Oman and incorporating the data with open-access biodiversity databases. We used QGIS 3.24.3 and R 4.2.2 packages for mapping and analyzing the distribution records. Our analyses revealed that the Persian Gulf exhibits proportionally higher diversity metrics than the Gulf of Oman for brachyuran crabs. Cluster analysis revealed that the Iranian coasts are relatively differentiated from the Arabian coasts of the Persian Gulf and the Gulf of Oman. The distribution and alpha species richness patterns per hexagonal cells were higher in the Iranian coastal waters, particularly around the Strait of Hormuz and Qeshm Island. Furthermore, the distribution and species richness of the Persian Gulf brachyuran crabs were positively correlated with temperature (°C) and calcite (mol.m-3), while negatively correlated with dissolved oxygen (mol.m-3). Although our analyses did not recognize the Persian Gulf as a center of endemism, but highlighted it as an important peripheral region with significant influences on the present-day diversity and distribution of northwestern Indian Ocean brachyuran crabs. We believe that the present results reveal new insights to be considered in conservation actions to protect marine biodiversity in underrepresented and ecologically unique regions such as the Persian Gulf.
{"title":"Species richness patterns of brachyuran crabs in the Persian Gulf and the Gulf of Oman","authors":"Nima Hashemian , Reza Naderloo , Adnan Shahdadi , Hanieh Saeedi","doi":"10.1016/j.dsr2.2025.105508","DOIUrl":"10.1016/j.dsr2.2025.105508","url":null,"abstract":"<div><div>The Persian Gulf is a shallow, semi-enclosed marginal sea basin characterized by a distinct geological history, harsh environmental conditions, and intermittent connection with the Indian Ocean during the Pleistocene glacial periods. Brachyuran crabs constitute a diverse component of the Persian Gulf fauna, distributed unevenly in the various habitats. The biodiversity and regional biogeographic data for the Persian Gulf and Gulf of Oman crab fauna are still poorly understood and rarely incorporated into global biodiversity databases. Here, we have addressed this shortfall by mapping the regional distributions of 262 species of brachyuran crabs in the Persian Gulf and the Gulf of Oman and incorporating the data with open-access biodiversity databases. We used QGIS 3.24.3 and R 4.2.2 packages for mapping and analyzing the distribution records. Our analyses revealed that the Persian Gulf exhibits proportionally higher diversity metrics than the Gulf of Oman for brachyuran crabs. Cluster analysis revealed that the Iranian coasts are relatively differentiated from the Arabian coasts of the Persian Gulf and the Gulf of Oman. The distribution and alpha species richness patterns per hexagonal cells were higher in the Iranian coastal waters, particularly around the Strait of Hormuz and Qeshm Island. Furthermore, the distribution and species richness of the Persian Gulf brachyuran crabs were positively correlated with temperature (°C) and calcite (mol.m-3), while negatively correlated with dissolved oxygen (mol.m-3). Although our analyses did not recognize the Persian Gulf as a center of endemism, but highlighted it as an important peripheral region with significant influences on the present-day diversity and distribution of northwestern Indian Ocean brachyuran crabs. We believe that the present results reveal new insights to be considered in conservation actions to protect marine biodiversity in underrepresented and ecologically unique regions such as the Persian Gulf.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"223 ","pages":"Article 105508"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The south-eastern Arabian Sea (SEAS) witnesses the confluence of the Arabian Sea and the Bay of Bengal waters along with an influence from both the summer and winter monsoon. As a result, the distinct hydrographic parameters are expected to modulate the diversity and abundance of planktic foraminifera in this region. Hence, 91 surface sediment samples covering a depth range from 25 m to 3150 m were analysed to establish region-specific planktic foraminiferal ecology. Overall, the water depth, seasonal chlorophyll-a and the mixed layer parameters significantly influence the planktic foraminiferal abundance in the SEAS. A total of 31 species of planktic foraminifera belonging to 17 genera were found. We report Globigerina bulloides as the most dominant species, preferring high productivity regions. Globigerina bulloides and Globigerinoides ruber exhibited opportunistic distribution patterns while region-specific preferences were observed for Globigerinita glutinata, N. dutertrei, Globorotalia cultrata and Trilobatus sacculifer. Globigerinita glutinata show a restricted seasonal occurrence while G. hexagonus is reported as a ubiquitous species. The ecological preferences of the planktic foraminifera inferred from the SEAS will help in reconstructing the past climatic conditions from this region.
{"title":"Assessing the ecological preferences of planktic foraminifera from the south-eastern Arabian Sea","authors":"Kumari Anjali , Thejasino Suokhrie , Rajeev Saraswat , Sujata R. Kurtarkar , Dinesh Kumar Naik , Dharmendra Pratap Singh , Rupal Dubey","doi":"10.1016/j.dsr2.2025.105527","DOIUrl":"10.1016/j.dsr2.2025.105527","url":null,"abstract":"<div><div>The south-eastern Arabian Sea (SEAS) witnesses the confluence of the Arabian Sea and the Bay of Bengal waters along with an influence from both the summer and winter monsoon. As a result, the distinct hydrographic parameters are expected to modulate the diversity and abundance of planktic foraminifera in this region. Hence, 91 surface sediment samples covering a depth range from 25 m to 3150 m were analysed to establish region-specific planktic foraminiferal ecology. Overall, the water depth, seasonal chlorophyll-a and the mixed layer parameters significantly influence the planktic foraminiferal abundance in the SEAS. A total of 31 species of planktic foraminifera belonging to 17 genera were found. We report <em>Globigerina bulloides</em> as the most dominant species, preferring high productivity regions. <em>Globigerina bulloides</em> and <em>Globigerinoides ruber</em> exhibited opportunistic distribution patterns while region-specific preferences were observed for <em>Globigerinita glutinata, N. dutertrei, Globorotalia cultrata</em> and <em>Trilobatus sacculifer. Globigerinita glutinata</em> show a restricted seasonal occurrence while <em>G. hexagonus</em> is reported as a ubiquitous species. The ecological preferences of the planktic foraminifera inferred from the SEAS will help in reconstructing the past climatic conditions from this region.</div></div>","PeriodicalId":11120,"journal":{"name":"Deep-sea Research Part Ii-topical Studies in Oceanography","volume":"223 ","pages":"Article 105527"},"PeriodicalIF":3.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864097","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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