Pub Date : 2025-01-06DOI: 10.1016/j.pocean.2025.103416
Bayoumy Mohamed, Nikolaos Skliris
This study investigates sea level changes in the Red Sea over the last 29 years (1993–2021) by analyzing long-term trends and interannual variations in the total sea level anomaly (SLA). The study also explores the role of thermosteric and halosteric changes and interannual variability of total SLA using an empirical orthogonal function (EOF) analysis and their relationship with large-scale climate modes. The results show that the trends of total and steric SLA were higher in the northern Red Sea (NRS) than in the southern Red Sea (SRS), influenced by low-salinity water inflow from the Aden Gulf. The average SLA trend in the Red Sea between 1993 and 2021 was about 4.17 ± 0.14 mm/year. However, an abrupt change was observed in SLA and its components, with accelerating trends in the post-2008 period compared to the pre-2008 period. This increase was mainly due to the thermosteric effect, which was positively enhanced throughout the Red Sea. The halosteric component in the NRS contributed negatively to the overall steric effect. The interannual SLA variability accounts for about 45 % of the total variability and can be partially explained by the influence of the El Nino Southern Oscillation.
{"title":"Recent sea level changes in the Red Sea: Thermosteric and halosteric contributions, and impacts of natural climate variability","authors":"Bayoumy Mohamed, Nikolaos Skliris","doi":"10.1016/j.pocean.2025.103416","DOIUrl":"https://doi.org/10.1016/j.pocean.2025.103416","url":null,"abstract":"This study investigates sea level changes in the Red Sea over the last 29 years (1993–2021) by analyzing long-term trends and interannual variations in the total sea level anomaly (SLA). The study also explores the role of thermosteric and halosteric changes and interannual variability of total SLA using an empirical orthogonal function (EOF) analysis and their relationship with large-scale climate modes. The results show that the trends of total and steric SLA were higher in the northern Red Sea (NRS) than in the southern Red Sea (SRS), influenced by low-salinity water inflow from the Aden Gulf. The average SLA trend in the Red Sea between 1993 and 2021 was about 4.17 ± 0.14 mm/year. However, an abrupt change was observed in SLA and its components, with accelerating trends in the post-2008 period compared to the pre-2008 period. This increase was mainly due to the thermosteric effect, which was positively enhanced throughout the Red Sea. The halosteric component in the NRS contributed negatively to the overall steric effect. The interannual SLA variability accounts for about 45 % of the total variability and can be partially explained by the influence of the El Nino Southern Oscillation.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"49 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142967795","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 : 2025-01-06DOI: 10.1016/j.pocean.2025.103417
Vladimir G. Dvoretsky, Alexander G. Dvoretsky
The Barents Sea is a productive region that is experiencing significant climatic fluctuations, making it essential to assess the impact of warming on the local ecosystems by summarizing information on different ecosystem components during various conditions and preceding trends. Our study aimed to reveal spatial patterns in the distribution and structure of zooplankton assemblages along a latitudinal gradient in summer 2013, a warm year, following the colder 2012. Cluster analysis grouped stations into three distinct categories based on the prevailing types of water masses, with higher abundance in colder waters due to the spring phase of plankton succession and higher biomasses in warmer waters. Boreal species were indicative of the southern and central sectors of the sea, while Arctic species and Copepoda nauplii were indicative of high-latitude stations. To elucidate the complex interplay between water mass characteristics, dynamics of nutrient conditions, and zooplankton community structure, both in situ and remote sensing data were used, with the latter covering a two-month period prior to sampling. Water temperature was identified as the primary factor influencing zooplankton assemblages, while nutrient concentrations, along with water currents, also played significant roles in controlling total abundance and biomass. Significant associations between environmental drivers and zooplankton variables were found when using lagged data, highlighting the importance of prior conditions for pelagic communities and shedding light on the underlying mechanisms driving zooplankton distribution and abundance patterns. This study provides valuable insights into the plankton ecology and community dynamics and creates a basis for further elucidating the effects of climate shifts on Arctic marine ecosystems.
{"title":"Summer zooplankton assemblages in the Barents Sea: Spatial variations and effects of environmental conditions as revealed from in situ and satellite data","authors":"Vladimir G. Dvoretsky, Alexander G. Dvoretsky","doi":"10.1016/j.pocean.2025.103417","DOIUrl":"https://doi.org/10.1016/j.pocean.2025.103417","url":null,"abstract":"The Barents Sea is a productive region that is experiencing significant climatic fluctuations, making it essential to assess the impact of warming on the local ecosystems by summarizing information on different ecosystem components during various conditions and preceding trends. Our study aimed to reveal spatial patterns in the distribution and structure of zooplankton assemblages along a latitudinal gradient in summer 2013, a warm year, following the colder 2012. Cluster analysis grouped stations into three distinct categories based on the prevailing types of water masses, with higher abundance in colder waters due to the spring phase of plankton succession and higher biomasses in warmer waters. Boreal species were indicative of the southern and central sectors of the sea, while Arctic species and Copepoda nauplii were indicative of high-latitude stations. To elucidate the complex interplay between water mass characteristics, dynamics of nutrient conditions, and zooplankton community structure, both in situ and remote sensing data were used, with the latter covering a two-month period prior to sampling. Water temperature was identified as the primary factor influencing zooplankton assemblages, while nutrient concentrations, along with water currents, also played significant roles in controlling total abundance and biomass. Significant associations between environmental drivers and zooplankton variables were found when using lagged data, highlighting the importance of prior conditions for pelagic communities and shedding light on the underlying mechanisms driving zooplankton distribution and abundance patterns. This study provides valuable insights into the plankton ecology and community dynamics and creates a basis for further elucidating the effects of climate shifts on Arctic marine ecosystems.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"4 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142967794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Internal ocean waves, such as internal tides and internal solitary waves (ISWs), have strong horizontal and vertical velocities and play an important role in ocean energy and material exchange. Field observations indicated that internal waves had a significant effect on hydrodynamics and sediment transport on the continental shelf. However, there remained a lack of field observations on how internal waves affect sediment transport on continental slopes. In this study, a seabed observation system was set up on the continental slope of the South China Sea for 13 days, which measured the high spatiotemporal resolution velocity and mixing of the internal tides and ISWs and sediment movements in the bottom boundary layer. The results showed that the internal tides and ISWs caused strong flows of more than 0.20 m/s near the seabed of the slope, which was much higher than the local sub-inertial currents (0.03 m/s) and barotropic tides (0.03 m/s). The velocity enhancement caused by internal tides and ISWs increased the bottom shear stress from 0.01 to 0.08 Pa. When the internal tidal velocity increased, the suspended sediment concentration (SSC) increased substantially from 5 mg/L to more than 40 mg/L. When the strongest ISWs passed through the observation site, the SSC increased several times, reaching 19 mg/L. Both internal tides and ISWs agitated seabed sediment and transported it downwards along the slope with sediment transport flux of 0.26 × 10-3 and 0.08 × 10-3 kg m−2 s−1, respectively.
{"title":"Field observations of internal waves triggered sediment movements at the northern South China Sea continental slope","authors":"Gaibo Zhao, Changwei Bian, Wensheng Jiang, Tao Wang, Xiaolei Liu, Jiwei Tian, Yonggang Jia","doi":"10.1016/j.pocean.2024.103412","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103412","url":null,"abstract":"Internal ocean waves, such as internal tides and internal solitary waves (ISWs), have strong horizontal and vertical velocities and play an important role in ocean energy and material exchange. Field observations indicated that internal waves had a significant effect on hydrodynamics and sediment transport on the continental shelf. However, there remained a lack of field observations on how internal waves affect sediment transport on continental slopes. In this study, a seabed observation system was set up on the continental slope of the South China Sea for 13 days, which measured the high spatiotemporal resolution velocity and mixing of the internal tides and ISWs and sediment movements in the bottom boundary layer. The results showed that the internal tides and ISWs caused strong flows of more than 0.20 m/s near the seabed of the slope, which was much higher than the local sub-inertial currents (0.03 m/s) and barotropic tides (0.03 m/s). The velocity enhancement caused by internal tides and ISWs increased the bottom shear stress from 0.01 to 0.08 Pa. When the internal tidal velocity increased, the suspended sediment concentration (SSC) increased substantially from 5 mg/L to more than 40 mg/L. When the strongest ISWs passed through the observation site, the SSC increased several times, reaching 19 mg/L. Both internal tides and ISWs agitated seabed sediment and transported it downwards along the slope with sediment transport flux of 0.26 × 10<ce:sup loc=\"post\">-3</ce:sup> and 0.08 × 10<ce:sup loc=\"post\">-3</ce:sup> kg m<ce:sup loc=\"post\">−2</ce:sup> s<ce:sup loc=\"post\">−1</ce:sup>, respectively.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"16 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925065","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 : 2024-12-26DOI: 10.1016/j.pocean.2024.103409
Andrea Corredor-Acosta, Alexander Galán, Gonzalo S. Saldías, Jorge I. Mardones, Johanna Medellín-Mora, Máximo Frangopulos, Takuhei Shiozaki, Naomi Harada, Humberto E. González, José L. Iriarte
Changes in phytoplankton composition and abundance are controlled by multiple factors, including physical forcing and nutrient stoichiometry. This study seeks to assess the interplay between the environmental and biogeochemical conditions in shaping the phytoplankton community structure in open ocean waters off western Patagonia. For this purpose, we used biological, hydrographic, and chemical data measured aboard the R/V Mirai during the austral summer of 2017, combined with remote sensing and reanalysis products. Although no first-order predictive relationships were found between the environmental and biological data, the results showed a latitudinal gradient of the phytoplankton structure, favoring maximum abundances of diatoms (∼10x104 cells L-1) in the northern area (∼43-48°S) characterized by high stratification and freshwater content. The high diatom abundances of Thalassiosira spp., Chaetoceros spp., Pseudo-nitzschia cf. australis and Pseudo-nitzschia cf. pseudodelicatissima taxa in this area results in a nutrient content decreases (nitrate < 9 μmol kg−1, phosphate < 0.9 μmol kg−1, silicic acid < 1.5 μmol kg−1), and low N:Si (<8) and N:P (<10) ratios. Nonetheless, the total dinoflagellates abundance was equal to or higher than those of diatoms (∼10.2x104 cells L-1) throughout most of the sampling region. Specifically, maximum abundances (∼6.3x104 cells L-1) of Karenia spp. were found in the north under the freshwater influence from the Gulf of Penas, where the highest ammonium:nitrate ratio (∼4 to 11.5) was recorded. In contrast, high dinoflagellate abundances of Azadinium spp. were found in the south (∼48-55°S), where an increase of nutrient content (nitrate ∼12μmol kg-1, phosphate ∼1 μmol kg-1, ammonium ∼0.4 μmol kg-1), and high N:Si and N:P ratios (∼35 and ∼12) were observed. This study highlights a major presence of potentially toxic phytoplankton species in the oceanic zone off northern Patagonia under conditions of strong latitudinal and cross-shore gradients in nutrient content and salinity, related to the interplay between oceanic water masses and freshwater input.
{"title":"Oceanic phytoplankton structure off western Patagonia during the austral summer: Implications for harmful algal blooms","authors":"Andrea Corredor-Acosta, Alexander Galán, Gonzalo S. Saldías, Jorge I. Mardones, Johanna Medellín-Mora, Máximo Frangopulos, Takuhei Shiozaki, Naomi Harada, Humberto E. González, José L. Iriarte","doi":"10.1016/j.pocean.2024.103409","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103409","url":null,"abstract":"Changes in phytoplankton composition and abundance are controlled by multiple factors, including physical forcing and nutrient stoichiometry. This study seeks to assess the interplay between the environmental and biogeochemical conditions in shaping the phytoplankton community structure in open ocean waters off western Patagonia. For this purpose, we used biological, hydrographic, and chemical data measured aboard the R/V Mirai during the austral summer of 2017, combined with remote sensing and reanalysis products. Although no first-order predictive relationships were found between the environmental and biological data, the results showed a latitudinal gradient of the phytoplankton structure, favoring maximum abundances of diatoms (∼10x10<ce:sup loc=\"post\">4</ce:sup> cells L<ce:sup loc=\"post\">-1</ce:sup>) in the northern area (∼43-48°S) characterized by high stratification and freshwater content. The high diatom abundances of <ce:italic>Thalassiosira</ce:italic> spp.<ce:italic>, Chaetoceros</ce:italic> spp.<ce:italic>, Pseudo-nitzschia</ce:italic> cf. <ce:italic>australis</ce:italic> and <ce:italic>Pseudo-nitzschia</ce:italic> cf. <ce:italic>pseudodelicatissima</ce:italic> taxa in this area results in a nutrient content decreases (nitrate < 9 μmol kg<ce:sup loc=\"post\">−1</ce:sup>, phosphate < 0.9 μmol kg<ce:sup loc=\"post\">−1</ce:sup>, silicic acid < 1.5 μmol kg<ce:sup loc=\"post\">−1</ce:sup>), and low N:Si (<8) and N:P (<10) ratios. Nonetheless, the total dinoflagellates abundance was equal to or higher than those of diatoms (∼10.2x10<ce:sup loc=\"post\">4</ce:sup> cells L<ce:sup loc=\"post\">-</ce:sup><ce:sup loc=\"post\">1</ce:sup>) throughout most of the sampling region. Specifically, maximum abundances (∼6.3x10<ce:sup loc=\"post\">4</ce:sup> cells L<ce:sup loc=\"post\">-</ce:sup><ce:sup loc=\"post\">1</ce:sup>) of <ce:italic>Karenia</ce:italic> spp. were found in the north under the freshwater influence from the Gulf of Penas, where the highest ammonium:nitrate ratio (∼4 to 11.5) was recorded. In contrast, high dinoflagellate abundances of <ce:italic>Azadinium</ce:italic> spp. were found in the south (∼48-55°S), where an increase of nutrient content (nitrate ∼12μmol kg<ce:sup loc=\"post\">-</ce:sup><ce:sup loc=\"post\">1</ce:sup>, phosphate ∼1 μmol kg<ce:sup loc=\"post\">-</ce:sup><ce:sup loc=\"post\">1</ce:sup>, ammonium ∼0.4 μmol kg<ce:sup loc=\"post\">-</ce:sup><ce:sup loc=\"post\">1</ce:sup>), and high N:Si and N:P ratios (∼35 and ∼12) were observed. This study highlights a major presence of potentially toxic phytoplankton species in the oceanic zone off northern Patagonia under conditions of strong latitudinal and cross-shore gradients in nutrient content and salinity, related to the interplay between oceanic water masses and freshwater input.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"1 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925064","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 : 2024-12-09DOI: 10.1016/j.pocean.2024.103407
T.B. Mashifane, L. Braby, M. Pikiso, S. Sunnassee–Taukoor, R.S. Rapolaki, M.N. Ragoasha
The Agulhas Current is the strongest western boundary current (WBC) in the Southern Hemisphere with a significant impact on the global climate. Through the Agulhas leakage, it transports warm, saline waters into the South Atlantic Ocean. In recent years, a warming trend has been highlighted in the Agulhas Current, with possible implications for dissolved oxygen ([O2]) due to the link between warming and reduced solubility – dynamics that remain relatively unknown in the region. To address this knowledge gap, we use the random forest regression algorithm to predict near–surface [O2] from multiple predictors in the Agulhas Current, presenting the first analysis of these dynamics. The Agulhas–RFR algorithm predicts [O2] exceptionally well, with permutation importance from the ensemble indicating that sea surface temperature (SST) is the highest–ranking predictor. Seasonal changes in solubility, wind, and productivity drive [O2] and the [O2] flux in the Agulhas Current. The seasonal [O2] flux to the atmosphere reaches –1.84 mol m−2 yr−1 during the austral winter across the Agulhas Current. A significant decreasing [O2] trend of up to –7 µmol kg−1 yr−1, attributed to warming, is revealed for the period from 2000 to 2023. Strengthening westerlies and cooling contribute to [O2] drawdown towards the Indian Ocean gyre. The Agulhas–RFR algorithm reveals a declining [O2] trend of –2.29 ± 0.61 µmol kg−1 yr−1 across the Agulhas Current for the study period, representing a 1.4% deoxygenation rate, which is slightly higher than global estimates.
{"title":"Machine learning algorithm reveals surface deoxygenation in the Agulhas Current due to warming","authors":"T.B. Mashifane, L. Braby, M. Pikiso, S. Sunnassee–Taukoor, R.S. Rapolaki, M.N. Ragoasha","doi":"10.1016/j.pocean.2024.103407","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103407","url":null,"abstract":"The Agulhas Current is the strongest western boundary current (WBC) in the Southern Hemisphere with a significant impact on the global climate. Through the Agulhas leakage, it transports warm, saline waters into the South Atlantic Ocean. In recent years, a warming trend has been highlighted in the Agulhas Current, with possible implications for dissolved oxygen ([O<ce:inf loc=\"post\">2</ce:inf>]) due to the link between warming and reduced solubility – dynamics that remain relatively unknown in the region. To address this knowledge gap, we use the random forest regression algorithm to predict near–surface [O<ce:inf loc=\"post\">2</ce:inf>] from multiple predictors in the Agulhas Current, presenting the first analysis of these dynamics. The Agulhas–RFR algorithm predicts [O<ce:inf loc=\"post\">2</ce:inf>] exceptionally well, with permutation importance from the ensemble indicating that sea surface temperature (SST) is the highest–ranking predictor. Seasonal changes in solubility, wind, and productivity drive [O<ce:inf loc=\"post\">2</ce:inf>] and the [O<ce:inf loc=\"post\">2</ce:inf>] flux in the Agulhas Current. The seasonal [O<ce:inf loc=\"post\">2</ce:inf>] flux to the atmosphere reaches –1.84 mol m<ce:sup loc=\"post\">−2</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup> during the austral winter across the Agulhas Current. A significant decreasing [O<ce:inf loc=\"post\">2</ce:inf>] trend of up to –7 µmol kg<ce:sup loc=\"post\">−1</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup>, attributed to warming, is revealed for the period from 2000 to 2023. Strengthening westerlies and cooling contribute to [O<ce:inf loc=\"post\">2</ce:inf>] drawdown towards the Indian Ocean gyre. The Agulhas–RFR algorithm reveals a declining [O<ce:inf loc=\"post\">2</ce:inf>] trend of –2.29 ± 0.61 µmol kg<ce:sup loc=\"post\">−1</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup> across the Agulhas Current for the study period, representing a 1.4% deoxygenation rate, which is slightly higher than global estimates.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"21 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821059","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}
Langmuir circulation (LC) and geostrophic effects are crucial physical processes that affect upper-ocean mixing. This study investigates the impact of LC on ocean mixing with a particular focus on geostrophic effects. By combining feedforward neural network (FNN) and Large Eddy Simulation (LES), this study simulated the interaction between varying intensities of LC and different geostrophic effects. The results revealed that the eddy viscosity coefficient in high-latitude areas exceeded that in mid-latitude areas, with this difference being most pronounced in the surface layer and gradually diminishing with depth. Analysis of the vertical momentum flux, upper mixed layer depth, and horizontal velocity shear characteristics demonstrates that geostrophic effects influence high-latitude ocean turbulence and mixing processes. Based on these findings, an improved LC parameterization scheme (KPPLT-FNN) incorporating geostrophic effects was developed, which relies on friction velocity, geostrophic effect, turbulent Langmuir number, and seawater depth. In GOTM, comparative analysis with observational data from COREII and the Ocean Climate Station Papa indicates that KPPLT-FNN demonstrates superior performance in simulating summer ocean temperature, ocean salinity, and winter mixed layer depth. Statistical analysis confirms that the simulation results incorporating geostrophic effects outperform those without such considerations. This study provides valuable insights into improving the accuracy of ocean model simulations.
{"title":"Parameterization of Langmuir circulation under geostrophic effects using the data-driven approach","authors":"Yu Gao, Jinbao Song, Shuang Li, Chengcheng Yu, Peng Hao","doi":"10.1016/j.pocean.2024.103403","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103403","url":null,"abstract":"Langmuir circulation (LC) and geostrophic effects are crucial physical processes that affect upper-ocean mixing. This study investigates the impact of LC on ocean mixing with a particular focus on geostrophic effects. By combining feedforward neural network (FNN) and Large Eddy Simulation (LES), this study simulated the interaction between varying intensities of LC and different geostrophic effects. The results revealed that the eddy viscosity coefficient in high-latitude areas exceeded that in mid-latitude areas, with this difference being most pronounced in the surface layer and gradually diminishing with depth. Analysis of the vertical momentum flux, upper mixed layer depth, and horizontal velocity shear characteristics demonstrates that geostrophic effects influence high-latitude ocean turbulence and mixing processes. Based on these findings, an improved LC parameterization scheme (KPPLT-FNN) incorporating geostrophic effects was developed, which relies on friction velocity, geostrophic effect, turbulent Langmuir number, and seawater depth. In GOTM, comparative analysis with observational data from COREII and the Ocean Climate Station Papa indicates that KPPLT-FNN demonstrates superior performance in simulating summer ocean temperature, ocean salinity, and winter mixed layer depth. Statistical analysis confirms that the simulation results incorporating geostrophic effects outperform those without such considerations. This study provides valuable insights into improving the accuracy of ocean model simulations.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"119 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821055","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 : 2024-12-05DOI: 10.1016/j.pocean.2024.103387
Ina Nilsen, Cecilie Hansen, Isaac C. Kaplan
As climate change is already altering ocean temperatures, there is an urgent need to understand how environmental changes will affect marine ecosystems. Although great efforts have been made to understand the impacts of ocean warming, there are still uncertainties regarding effects on lower trophic levels and how these may propagate to higher trophic levels. In this study, physics from three different climate projections (SPP1-2.6, SSP2-4.5 and SSP5-8.5) were applied to study the impact of rising temperatures in the Nordic and Barents Seas Atlantis ecosystem model (NoBa Atlantis). We also included variation in phyto- and zooplankton levels to account for the uncertainty regarding how lower trophic levels might respond to climate change. This approach by us is the first study where three different sets of physics have been applied to an end-to-end ecosystem model representing the Nordic and Barents Seas. We therefore treat the projected results with caution, and focus on the underlying mechanisms that drive the changes, to inform future ecosystem studies. The spatial nature of the model (a “shifting chessboard”) allowed us to study how local changes in temperature and prey could affect entire populations. For instance, the thermal niches of mesopelagic fish allowed for an increase in abundance in northern areas, benefiting predators such as blue whiting. On the other hand, thermal limits of capelin together with zooplankton overlap resulted in declines, which subsequently led to reduction in cod growth. This study demonstrates how ecosystem studies could benefit from both modeling and empirical studies that consider not only broad-brush impacts on primary production and trophic transfer, but also spatial considerations of local predator–prey interactions, thermal habitat and spawning-area suitability.
{"title":"A shifting chessboard: Projections of prawn, capelin, mesopelagic fish, zooplankton, and their Nordic and Barents Seas food web under climate change","authors":"Ina Nilsen, Cecilie Hansen, Isaac C. Kaplan","doi":"10.1016/j.pocean.2024.103387","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103387","url":null,"abstract":"As climate change is already altering ocean temperatures, there is an urgent need to understand how environmental changes will affect marine ecosystems. Although great efforts have been made to understand the impacts of ocean warming, there are still uncertainties regarding effects on lower trophic levels and how these may propagate to higher trophic levels. In this study, physics from three different climate projections (SPP1-2.6, SSP2-4.5 and SSP5-8.5) were applied to study the impact of rising temperatures in the Nordic and Barents Seas Atlantis ecosystem model (NoBa Atlantis). We also included variation in phyto- and zooplankton levels to account for the uncertainty regarding how lower trophic levels might respond to climate change. This approach by us is the first study where three different sets of physics have been applied to an end-to-end ecosystem model representing the Nordic and Barents Seas. We therefore treat the projected results with caution, and focus on the underlying mechanisms that drive the changes, to inform future ecosystem studies. The spatial nature of the model (a “shifting chessboard”) allowed us to study how local changes in temperature and prey could affect entire populations. For instance, the thermal niches of mesopelagic fish allowed for an increase in abundance in northern areas, benefiting predators such as blue whiting. On the other hand, thermal limits of capelin together with zooplankton overlap resulted in declines, which subsequently led to reduction in cod growth. This study demonstrates how ecosystem studies could benefit from both modeling and empirical studies that consider not only broad-brush impacts on primary production and trophic transfer, but also spatial considerations of local predator–prey interactions, thermal habitat and spawning-area suitability.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"21 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821050","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 Kuroshio has been long thought to be disadvantageous as nursery grounds for larval fishes due to the low plankton standing stocks under the oligotrophic conditions. Despite of the potential risk for survival and growth, early life stages of various fishes appear abundantly in the Kuroshio and its neighboring waters. Here, we report what kind of taxonomic groups establish community structure of larval fishes in the Continental shelf waters (CW) and the Kuroshio (KW). 16 orders and 78 families were classified in the present study. Mesopelagic fishes more abundantly appeared in the KW than in the CW, while larval fish abundance was not different between the two areas. Multivariate analysis demonstrated the regional difference of the taxonomic compositions, represented by Callionymidae, Bothidae, Labridae and Bregmacerotidae for the CW and Gonostomatidae, Myctophidae and Notosudidae for the KW. Abundance of fish larvae to ambient salinity exhibited significantly positive correlations for Gonostomatidae, Sigmops gracilis and Myctophum orientale predominated in the KW and negative correlations for Labridae appeared abundantly in the CW. These results suggest that mixture of advected specimens from the coastal and Kuroshio waters also contribute to larval fish community with high biodiversity and comparable abundance between the Kuroshio and its neighboring waters.
{"title":"Community structure of fish larvae associated with advections of the Kuroshio and its neighboring waters","authors":"Toru Kobari, Yusuke Manako, Airi Hara, Kaori Yamanoue, Takafumi Azuma, Ryuji Fukuda, Yi-Chen Wang, Masafumi Kodama, Gen Kume","doi":"10.1016/j.pocean.2024.103386","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103386","url":null,"abstract":"The Kuroshio has been long thought to be disadvantageous as nursery grounds for larval fishes due to the low plankton standing stocks under the oligotrophic conditions. Despite of the potential risk for survival and growth, early life stages of various fishes appear abundantly in the Kuroshio and its neighboring waters. Here, we report what kind of taxonomic groups establish community structure of larval fishes in the Continental shelf waters (CW) and the Kuroshio (KW). 16 orders and 78 families were classified in the present study. Mesopelagic fishes more abundantly appeared in the KW than in the CW, while larval fish abundance was not different between the two areas. Multivariate analysis demonstrated the regional difference of the taxonomic compositions, represented by Callionymidae, Bothidae, Labridae and Bregmacerotidae for the CW and Gonostomatidae, Myctophidae and Notosudidae for the KW. Abundance of fish larvae to ambient salinity exhibited significantly positive correlations for Gonostomatidae, <ce:italic>Sigmops gracilis</ce:italic> and <ce:italic>Myctophum orientale</ce:italic> predominated in the KW and negative correlations for Labridae appeared abundantly in the CW. These results suggest that mixture of advected specimens from the coastal and Kuroshio waters also contribute to larval fish community with high biodiversity and comparable abundance between the Kuroshio and its neighboring waters.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"178 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788910","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}
Quantification of abundance and food consumption of seabirds are key to understand characteristics and ecological functions of local marine ecosystem due to their abundance and diversity in foraging areas, habitat, behavior, mobility and prey types. This study aimed to quantify seabird abundance in pelagic areas in the eastern Indian sector of the Southern Ocean (80–150E°) based on an at-sea observational study conducted during the 2018/19 austral summer season. We estimated food consumption by seabirds based on their biomass, estimated field metabolic rates, number of days spent in the areas, and diet composition. Among the five functional seabird groups (penguins, albatrosses/giant petrels, shearwaters, petrels/Charadriiformes, prions/storm-petrels), shearwaters, non-Antarctic resident, were the most dominant taxa both by abundance (15,650,000 birds) and biomass (9,332 tonnes) in the study area during the summer. Most of the prey consumed by all seabirds in the area was presumed to be Antarctic krill (55,504 tonnes) and pelagic fishes (91,695 tonnes), such as myctophids. Although the total food consumption by the seabirds during the summer (209,973 tonnes) was lower than that reported in the Antarctic neritic areas (e.g., 753,000 tonnes in the neighboring Prydz Bay region), the higher proportion of non-resident shearwaters in biomass and estimated food consumption (85%) were the characteristic of the study area. Our results highlight the characteristics of the ecological importance of the study area in which seabirds consume Antarctic krill and pelagic fishes in the upper layer of the water column, and its nutrients are easily transported by the seabirds as their subcutaneous fat or stomach oil to the outside of the areas.
{"title":"Abundance and estimated food consumption of seabirds in the pelagic ecosystem in the eastern Indian sector of the Southern Ocean","authors":"Nobuo Kokubun, Kohei Hamabe, Nodoka Yamada, Hiroko Sasaki, Bungo Nishizawa, Yutaka Watanuki, Hiroto Murase","doi":"10.1016/j.pocean.2024.103385","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103385","url":null,"abstract":"Quantification of abundance and food consumption of seabirds are key to understand characteristics and ecological functions of local marine ecosystem due to their abundance and diversity in foraging areas, habitat, behavior, mobility and prey types. This study aimed to quantify seabird abundance in pelagic areas in the eastern Indian sector of the Southern Ocean (80–150E°) based on an at-sea observational study conducted during the 2018/19 austral summer season. We estimated food consumption by seabirds based on their biomass, estimated field metabolic rates, number of days spent in the areas, and diet composition. Among the five functional seabird groups (penguins, albatrosses/giant petrels, shearwaters, petrels/Charadriiformes, prions/storm-petrels), shearwaters, non-Antarctic resident, were the most dominant taxa both by abundance (15,650,000 birds) and biomass (9,332 tonnes) in the study area during the summer. Most of the prey consumed by all seabirds in the area was presumed to be Antarctic krill (55,504 tonnes) and pelagic fishes (91,695 tonnes), such as myctophids. Although the total food consumption by the seabirds during the summer (209,973 tonnes) was lower than that reported in the Antarctic neritic areas (e.g., 753,000 tonnes in the neighboring Prydz Bay region), the higher proportion of non-resident shearwaters in biomass and estimated food consumption (85%) were the characteristic of the study area. Our results highlight the characteristics of the ecological importance of the study area in which seabirds consume Antarctic krill and pelagic fishes in the upper layer of the water column, and its nutrients are easily transported by the seabirds as their subcutaneous fat or stomach oil to the outside of the areas.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"113 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788911","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 : 2024-11-30DOI: 10.1016/j.pocean.2024.103389
Luca Russo, Matteo Loschi, Daniele Bellardini, Roberta Congestri, Michael W. Lomas, Simone Libralato, Domenico D’Alelio
Ocean warming can affect plankton both directly, through altered metabolic activities, and indirectly, modifying the physical–chemical properties of the water column, with possible effects on ecosystem functioning. To evaluate the combined action of warming-related physiological responses and environmental changes on plankton assemblage functioning, we carried out a long-term analysis (from 1994 to 2019) of the Bermuda Atlantic Time-series Study (BATS) dataset where ocean warming and stratification have driven a decrease in net primary production over the last decade. Using the time series of plankton observations, we assembled 1000 replicates of a food web model for each year. We observed that the total flow of matter through the model remained constant over time, despite the increased oligotrophication, due to global warming, after 2014. In fact, the plankton food web remained robust through re-modulated trophic interactions with an increased detritivory to herbivory ratio of the food web over time. Moreover, there was difficulty to re-establish broken trophic connections of the food web (increased relative internal ascendency) due to global warming. Thanks to trophic plasticity, the reduced zooplankton dependence on herbivory was compensated by significant increase in the dependence on carnivory and detritivory, highlighting the crucial role of trophic interactions in buffering significant environmental short-term changes.
{"title":"Food web analysis shows an exacerbated dependence of zooplankton on detritus in oligotrophic systems due to ocean warming","authors":"Luca Russo, Matteo Loschi, Daniele Bellardini, Roberta Congestri, Michael W. Lomas, Simone Libralato, Domenico D’Alelio","doi":"10.1016/j.pocean.2024.103389","DOIUrl":"https://doi.org/10.1016/j.pocean.2024.103389","url":null,"abstract":"Ocean warming can affect plankton both directly, through altered metabolic activities, and indirectly, modifying the physical–chemical properties of the water column, with possible effects on ecosystem functioning. To evaluate the combined action of warming-related physiological responses and environmental changes on plankton assemblage functioning, we carried out a long-term analysis (from 1994 to 2019) of the Bermuda Atlantic Time-series Study (BATS) dataset where ocean warming and stratification have driven a decrease in net primary production over the last decade. Using the time series of plankton observations, we assembled 1000 replicates of a food web model for each year. We observed that the total flow of matter through the model remained constant over time, despite the increased oligotrophication, due to global warming, after 2014. In fact, the plankton food web remained robust through re-modulated trophic interactions with an increased detritivory to herbivory ratio of the food web over time. Moreover, there was difficulty to re-establish broken trophic connections of the food web (increased relative internal ascendency) due to global warming. Thanks to trophic plasticity, the reduced zooplankton dependence on herbivory was compensated by significant increase in the dependence on carnivory and detritivory, highlighting the crucial role of trophic interactions in buffering significant environmental short-term changes.","PeriodicalId":20620,"journal":{"name":"Progress in Oceanography","volume":"82 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788923","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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