Continental Shelf Research最新文献

Vertical circulation and heat flux of coastal ocean fronts in the northwestern South China Sea

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-04-18 DOI: 10.1016/j.csr.2025.105478

Keyi Tan , Lingling Xie , Junyi Li , Mingming Li , Qiang Li , Quanan Zheng

This study investigates the 3D structure and vertical circulation of the coastal ocean fronts in the northwestern South China Sea (NWSCS) by applying the generalized Omega equation to cruise observations in late August and early September 2018. The results reveal three summer density front zones (SUF1∼3) in the surface and subsurface layers. SUF1 is distributed along the coast with water depths shallower than 20 m and a density gradient larger than 0.2 × 10⁻³ kg m⁻⁴. It extends vertically from surface to bottom and is dominated by salinity gradient. In contrast, SUF2 and SUF3 are temperature-dominated frontal zones appearing in the offshore subsurface layer. SUF2 is in the cross-shelf direction between the 20-m and 40-m isobaths associated with upwelling waters originating from the south. The observed submesoscale fronts have a Rossby number of O(1). The diagnosed vertical velocities indicate that an upwelling peak of 4.2 × 10⁻⁵ m s⁻¹ is located near the coast in SUF1, while, in contrast, a maximum vertical velocity of −5.1 × 10⁻⁵ m s⁻¹ in the cross-shelf SUF2. Dynamic analysis results indicate that ageostrophic advection is the dominant term. The vertical heat fluxes derived from the vertical velocity and temperature anomaly are mainly positive both in SUF1 and SUF2, with a maximum value of 279.5 W m⁻² and 418.8 W m⁻², respectively, which are one order larger than the sea surface heat flux during the observation.

{"title":"Vertical circulation and heat flux of coastal ocean fronts in the northwestern South China Sea","authors":"Keyi Tan , Lingling Xie , Junyi Li , Mingming Li , Qiang Li , Quanan Zheng","doi":"10.1016/j.csr.2025.105478","DOIUrl":"10.1016/j.csr.2025.105478","url":null,"abstract":"<div><div>This study investigates the 3D structure and vertical circulation of the coastal ocean fronts in the northwestern South China Sea (NWSCS) by applying the generalized Omega equation to cruise observations in late August and early September 2018. The results reveal three summer density front zones (SUF1∼3) in the surface and subsurface layers. SUF1 is distributed along the coast with water depths shallower than 20 m and a density gradient larger than 0.2 × 10<sup>−3</sup> kg m<sup>−4</sup>. It extends vertically from surface to bottom and is dominated by salinity gradient. In contrast, SUF2 and SUF3 are temperature-dominated frontal zones appearing in the offshore subsurface layer. SUF2 is in the cross-shelf direction between the 20-m and 40-m isobaths associated with upwelling waters originating from the south. The observed submesoscale fronts have a Rossby number of <em>O</em>(1). The diagnosed vertical velocities indicate that an upwelling peak of 4.2 × 10<sup>−5</sup> m s<sup>−1</sup> is located near the coast in SUF1, while, in contrast, a maximum vertical velocity of −5.1 × 10<sup>−5</sup> m s<sup>−1</sup> in the cross-shelf SUF2. Dynamic analysis results indicate that ageostrophic advection is the dominant term. The vertical heat fluxes derived from the vertical velocity and temperature anomaly are mainly positive both in SUF1 and SUF2, with a maximum value of 279.5 W m<sup>−2</sup> and 418.8 W m<sup>−2</sup>, respectively, which are one order larger than the sea surface heat flux during the observation.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"290 ","pages":"Article 105478"},"PeriodicalIF":2.1,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870034","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}

引用次数: 0

Reproduction features of ocean quahog, Arctica islandica (Linnaeus, 1767), in the White Sea 白海大洋魁蚶(Arctica islandica (Linnaeus, 1767))的繁殖特征

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-04-07 DOI: 10.1016/j.csr.2025.105469

Alexandra Vladimirovna Gerasimova , Lyudmila Pavlovna Flyachinskaya , Lezin Petr Andreevich , Nadezhda Andreevna Filippova , Alexandra Sergeevna Kudryashova , Alexey Ivanovich Starkov , Nikolai Vladimirovich Maximovich

The gametogenic cycle of ocean quahog, Arctica islandica, was investigated using specimens collected from a near-shore bed (10–15 m deep) in the Kandalaksha Bay of the White Sea during five summer seasons (1983, 1984, 2011, 2015, 2017). At present, the White Sea is the eastern distribution boundary of this mollusk. Local environmental conditions there differ considerably from those in other parts of its range, and many characteristics of the quahog populations in the White Sea are still poorly understood. In this study, we examined gonads from 384 ocean quahogs with shell length over 30 mm prepared with the use of standard histological techniques. The results showed that the reproductive cycle features of A. islandica in the White Sea were generally similar to those in other parts of its distribution. Clams in the spawning state were found mainly from the second half of July to October at a near-bottom water temperature of 9–15 °C. Both average (60–70 μm) and maximum (92–95 μm) size of mature oocytes of ocean quahogs from the White Sea were similar to those in North Atlantic populations. At the same time, we noted substantial interannual shifts in the spawning activity of A. islandica and showed that they reflected interannual changes in hydrological characteristics. However, it is unlikely that these shifts may affect the overall recruitment success of the population of this species.

利用五个夏季（1983、1984、2011、2015、2017）从白海康达拉沙湾近岸海床（10-15 米深）采集的标本，研究了大洋魁蚶的配子周期。目前，白海是这种软体动物的东部分布边界。当地的环境条件与其分布区的其他地区有很大不同，人们对白海魁蚶种群的许多特征仍知之甚少。在这项研究中，我们采用标准的组织学技术，对 384 个贝壳长度超过 30 毫米的大洋魁蚶的性腺进行了检查。结果表明，白海岛蛤的生殖周期特征与其分布的其他地区基本相似。产卵状态的蛤蜊主要出现在 7 月下半月至 10 月，近底水温为 9-15 °C。白海大洋魁蚶成熟卵母细胞的平均尺寸（60-70 μm）和最大尺寸（92-95 μm）与北大西洋种群相似。与此同时，我们注意到岛氏魁鲤的产卵活动在年际间发生了很大变化，并表明这些变化反映了水文特征的年际变化。不过，这些变化不太可能影响该物种种群的整体繁殖成功率。

{"title":"Reproduction features of ocean quahog, Arctica islandica (Linnaeus, 1767), in the White Sea","authors":"Alexandra Vladimirovna Gerasimova , Lyudmila Pavlovna Flyachinskaya , Lezin Petr Andreevich , Nadezhda Andreevna Filippova , Alexandra Sergeevna Kudryashova , Alexey Ivanovich Starkov , Nikolai Vladimirovich Maximovich","doi":"10.1016/j.csr.2025.105469","DOIUrl":"10.1016/j.csr.2025.105469","url":null,"abstract":"<div><div>The gametogenic cycle of ocean quahog, <em>Arctica islandica</em>, was investigated using specimens collected from a near-shore bed (10–15 m deep) in the Kandalaksha Bay of the White Sea during five summer seasons (1983, 1984, 2011, 2015, 2017). At present, the White Sea is the eastern distribution boundary of this mollusk. Local environmental conditions there differ considerably from those in other parts of its range, and many characteristics of the quahog populations in the White Sea are still poorly understood. In this study, we examined gonads from 384 ocean quahogs with shell length over 30 mm prepared with the use of standard histological techniques. The results showed that the reproductive cycle features <em>of A. islandica</em> in the White Sea were generally similar to those in other parts of its distribution. Clams in the spawning state were found mainly from the second half of July to October at a near-bottom water temperature of 9–15 °C. Both average (60–70 μm) and maximum (92–95 μm) size of mature oocytes of ocean quahogs from the White Sea were similar to those in North Atlantic populations. At the same time, we noted substantial interannual shifts in the spawning activity of <em>A. islandica</em> and showed that they reflected interannual changes in hydrological characteristics. However, it is unlikely that these shifts may affect the overall recruitment success of the population of this species.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"290 ","pages":"Article 105469"},"PeriodicalIF":2.1,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821569","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}

引用次数: 0

Specific oceanographic conditions reflect meiofaunal communities: the case of a semi-enclosed gulf (Pagasitikos Gulf, Eastern Mediterranean)

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-04-05 DOI: 10.1016/j.csr.2025.105470

K. Voulgaris, D. Vafidis

Semi-enclosed gulfs exhibit distinct oceanographic conditions, influencing the inhabiting organisms and communities. Analyzing samples from 55 stations taken at 10 cm sediment depth in spring 2023 and belonging to three zones with different nutrient profiles, the meiofaunal communities in Pagasitikos gulf were examined, while their relationship with sediment properties, water chemistry and oceanographic conditions were investigated. Highest meiofaunal densities were observed in the internal gulf (458–1538 ind/10 cm²) near the main urban area, with lowest reported for the upper external gulf (36–594 ind/10 cm²). Two stations showed unusually high ciliate densities (454 and 598 ind/10 cm²) that could not be explained by any of the examined parameters. Highest richness but lowest evenness, Shannon and Simpson indices were reported for the internal gulf, followed by the lower external gulf, while the upper external zone showed lowest values. Multivariate analyses showed that all three nutrient zones are associated with distinct meiofaunal communities, with depth and sand content being the most important factors influencing the meiofaunal communities, while also discussing the potential effect of anthropogenic activities. Total organic carbon did not explain differences in meiofaunal composition, stressing the need for more precise measurements. This study showcases that gulf-specific oceanographic conditions such as water and nutrient stratification and hydrodynamics can play a key role in shaping meiofaunal communities.

{"title":"Specific oceanographic conditions reflect meiofaunal communities: the case of a semi-enclosed gulf (Pagasitikos Gulf, Eastern Mediterranean)","authors":"K. Voulgaris, D. Vafidis","doi":"10.1016/j.csr.2025.105470","DOIUrl":"10.1016/j.csr.2025.105470","url":null,"abstract":"<div><div>Semi-enclosed gulfs exhibit distinct oceanographic conditions, influencing the inhabiting organisms and communities. Analyzing samples from 55 stations taken at 10 cm sediment depth in spring 2023 and belonging to three zones with different nutrient profiles, the meiofaunal communities in Pagasitikos gulf were examined, while their relationship with sediment properties, water chemistry and oceanographic conditions were investigated. Highest meiofaunal densities were observed in the internal gulf (458–1538 ind/10 cm<sup>2</sup>) near the main urban area, with lowest reported for the upper external gulf (36–594 ind/10 cm<sup>2</sup>). Two stations showed unusually high ciliate densities (454 and 598 ind/10 cm<sup>2</sup>) that could not be explained by any of the examined parameters. Highest richness but lowest evenness, Shannon and Simpson indices were reported for the internal gulf, followed by the lower external gulf, while the upper external zone showed lowest values. Multivariate analyses showed that all three nutrient zones are associated with distinct meiofaunal communities, with depth and sand content being the most important factors influencing the meiofaunal communities, while also discussing the potential effect of anthropogenic activities. Total organic carbon did not explain differences in meiofaunal composition, stressing the need for more precise measurements. This study showcases that gulf-specific oceanographic conditions such as water and nutrient stratification and hydrodynamics can play a key role in shaping meiofaunal communities.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"289 ","pages":"Article 105470"},"PeriodicalIF":2.1,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808248","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}

引用次数: 0

Tidal amplification and shallow water tides in a mixed semidiurnal coastal lagoon

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-04-01 DOI: 10.1016/j.csr.2025.105468

Braulio Juarez , Amaia Ruiz de Alegría-Arzaburu , Julian Garcia Walther

Tidal amplification of the semidiurnal M₂ component and the generation of shallow water tides were studied along a mixed semidiurnal system. Month-long water level and current velocity data were collected using three acoustic Doppler current profilers. These profilers were moored at depths of around 15 m in three locations: 10 km inland from the mouth of the lagoon, within the central region, and near the head of the lagoon. Harmonic and spectral analysis applied to observations showed landward amplification of a semidiurnal tidal wave and the generation of high frequency tides. A wavelet analysis also depicted the temporal variability of each frequency band showing the generation of shallow water tides that coincided with the spring tidal cycle. The observed tidal amplification and generation of shallow water tides were reproduced using a numerical model to explore the mechanisms involved in the generation of high frequency harmonics and to determine their spatial distribution. An analytical model replicated the amplification of M₂ in an idealized elongated channel under high frictional forces. The four nonlinear mechanisms that led to shallow water tides generation were computed and a relationship with velocities was established using wavelet coherence. The even quadratic frictional term showed the highest coherence with the third diurnal (i.e. MK3), and seventh diurnal (i.e. 4MO₇) frequency band. The fourth diurnal (i.e. M₄) band was consistently related with advection and the odd frictional term. The contribution of this research is twofold: firstly, it provides new observational evidence on tidal amplification due to friction and channel geometry; and it explores the mechanisms that can generate shallow water tides. These results enhance our understanding of tidal dynamics in coastal semi-enclosed bodies, such as coastal lagoons or estuaries.

{"title":"Tidal amplification and shallow water tides in a mixed semidiurnal coastal lagoon","authors":"Braulio Juarez , Amaia Ruiz de Alegría-Arzaburu , Julian Garcia Walther","doi":"10.1016/j.csr.2025.105468","DOIUrl":"10.1016/j.csr.2025.105468","url":null,"abstract":"<div><div>Tidal amplification of the semidiurnal M<sub>2</sub> component and the generation of shallow water tides were studied along a mixed semidiurnal system. Month-long water level and current velocity data were collected using three acoustic Doppler current profilers. These profilers were moored at depths of around 15 m in three locations: 10 km inland from the mouth of the lagoon, within the central region, and near the head of the lagoon. Harmonic and spectral analysis applied to observations showed landward amplification of a semidiurnal tidal wave and the generation of high frequency tides. A wavelet analysis also depicted the temporal variability of each frequency band showing the generation of shallow water tides that coincided with the spring tidal cycle. The observed tidal amplification and generation of shallow water tides were reproduced using a numerical model to explore the mechanisms involved in the generation of high frequency harmonics and to determine their spatial distribution. An analytical model replicated the amplification of M<sub>2</sub> in an idealized elongated channel under high frictional forces. The four nonlinear mechanisms that led to shallow water tides generation were computed and a relationship with velocities was established using wavelet coherence. The even quadratic frictional term showed the highest coherence with the third diurnal (i.e. MK3), and seventh diurnal (i.e. 4MO<sub>7</sub>) frequency band. The fourth diurnal (i.e. M<sub>4</sub>) band was consistently related with advection and the odd frictional term. The contribution of this research is twofold: firstly, it provides new observational evidence on tidal amplification due to friction and channel geometry; and it explores the mechanisms that can generate shallow water tides. These results enhance our understanding of tidal dynamics in coastal semi-enclosed bodies, such as coastal lagoons or estuaries.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"289 ","pages":"Article 105468"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769338","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}

引用次数: 0

The dynamics of the inner-shelf suspended sediments based on ADCP records and Rouse theory

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-03-29 DOI: 10.1016/j.csr.2025.105467

Guilherme O. Cruz, Carlos A.F. Schettini

The present study investigates the suspended sediment dynamics on the southern Brazilian continental shelf in the fluvial influence region of the Rio de la Plata and Patos Lagoon. Estimates of suspended sediment concentration (SSC) in the water column were obtained using data from a Doppler-effect acoustic Doppler current profiler (ADCP) and were compared with theoretical profiles obtained using Rouse's theory. To construct the theoretical profile, sediment settling velocity and shear velocity are necessary. The former was iteratively estimated to minimize the error between observed and modeled profiles. The latter was obtained from ADCP measurements. The comparison between observed and modeled profiles underwent a validation process considering the shape of the observed profile and environmental energy conditions. For the period of analyzed data, there was agreement between observed and modeled profiles 56 % of the time. When energy conditions were low (39 % of the time), and the gradient profile of SSC had higher concentrations near the surface than bottom (5 %), Rouse's theory did not apply. These results indicate that the main source of sediment in the water column is due to exchanges with the bottom. Although the study area is near the mouth of Patos Lagoon, the role of horizontal advection was negligible. By indirect inference, it was obtained that the median sediment size was 25 μm, with maximum values around 60 μm, which coincides with values suggested in the literature for coastal waters, with a median settling velocity of 0.14 cm/s. During periods of more energetic hydrodynamic conditions, downwelling events were associated with northward longitudinal currents, while upwelling occurred with southward currents. When the flow was directed northward, more material was transported near the bottom compared to southward flow.

{"title":"The dynamics of the inner-shelf suspended sediments based on ADCP records and Rouse theory","authors":"Guilherme O. Cruz, Carlos A.F. Schettini","doi":"10.1016/j.csr.2025.105467","DOIUrl":"10.1016/j.csr.2025.105467","url":null,"abstract":"<div><div>The present study investigates the suspended sediment dynamics on the southern Brazilian continental shelf in the fluvial influence region of the Rio de la Plata and Patos Lagoon. Estimates of suspended sediment concentration (SSC) in the water column were obtained using data from a Doppler-effect acoustic Doppler current profiler (ADCP) and were compared with theoretical profiles obtained using Rouse's theory. To construct the theoretical profile, sediment settling velocity and shear velocity are necessary. The former was iteratively estimated to minimize the error between observed and modeled profiles. The latter was obtained from ADCP measurements. The comparison between observed and modeled profiles underwent a validation process considering the shape of the observed profile and environmental energy conditions. For the period of analyzed data, there was agreement between observed and modeled profiles 56 % of the time. When energy conditions were low (39 % of the time), and the gradient profile of SSC had higher concentrations near the surface than bottom (5 %), Rouse's theory did not apply. These results indicate that the main source of sediment in the water column is due to exchanges with the bottom. Although the study area is near the mouth of Patos Lagoon, the role of horizontal advection was negligible. By indirect inference, it was obtained that the median sediment size was 25 μm, with maximum values around 60 μm, which coincides with values suggested in the literature for coastal waters, with a median settling velocity of 0.14 cm/s. During periods of more energetic hydrodynamic conditions, downwelling events were associated with northward longitudinal currents, while upwelling occurred with southward currents. When the flow was directed northward, more material was transported near the bottom compared to southward flow.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"289 ","pages":"Article 105467"},"PeriodicalIF":2.1,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759451","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}

引用次数: 0

Water masses distribution over the continental shelf off the Doce River (19.65°S), Southeastern Brazil: A fuzzy cluster analysis

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-03-25 DOI: 10.1016/j.csr.2025.105462

Tayná Rosa Martins Paiva, Gabriela Corrêa Brasileiro, Guilherme Nogueira Mill, Eduarda Sousa Rangel, Renato David Ghisolfi

This study investigates the seasonal variability of water masses across three sectors of the Espírito Santo Continental Shelf (ESCS): the North Sector, River Sector, and Environmental Protected Area (EPA) Sector. Utilizing a comprehensive dataset collected between November 2018 and July 2023, we applied fuzzy clustering methods to outline three water masses — Coastal Water (CW), Tropical Water (TW), and South Atlantic Central Water (SACW) — and analyze their distribution across the sectors. Our findings reveal distinct seasonal patterns in these water masses’ distribution and properties, influenced by factors like river discharge, coastal upwelling, and net heat flux. Absolute salinity distribution showed less saline river runoff water constrained to the coastal region around the Doce River mouth and eventually in the coastal North Sector due to increased continental discharge associated with reversal southerly winds. Winter is an exception to the conservative temperature and absolute salinity distribution due to the homogeneity of cold column water and the lower input of freshwater. Particularly noteworthy is the seasonal variability observed in the River Sector, where the influence of freshwater discharge from the Doce River significantly impacts water masses distribution. CW occurrence follows the distribution of absolute salinity and the area affected by the river plume, TW is associated with the Brazil Current, and SACW occurs over the continental shelf throughout the year (despite the weak thermal gradient during the winter). At the surface, TW prevails at all sectors beyond the river influence during the autumn and past the 30 m-isobath in the remaining seasons due to upwelled waters. This study provides valuable insights into the complex interactions shaping the oceanographic characteristics of the ESCS, highlighting the importance of considering seasonal variability in understanding coastal marine ecosystems.

{"title":"Water masses distribution over the continental shelf off the Doce River (19.65°S), Southeastern Brazil: A fuzzy cluster analysis","authors":"Tayná Rosa Martins Paiva, Gabriela Corrêa Brasileiro, Guilherme Nogueira Mill, Eduarda Sousa Rangel, Renato David Ghisolfi","doi":"10.1016/j.csr.2025.105462","DOIUrl":"10.1016/j.csr.2025.105462","url":null,"abstract":"<div><div>This study investigates the seasonal variability of water masses across three sectors of the Espírito Santo Continental Shelf (ESCS): the North Sector, River Sector, and Environmental Protected Area (EPA) Sector. Utilizing a comprehensive dataset collected between November 2018 and July 2023, we applied fuzzy clustering methods to outline three water masses — Coastal Water (CW), Tropical Water (TW), and South Atlantic Central Water (SACW) — and analyze their distribution across the sectors. Our findings reveal distinct seasonal patterns in these water masses’ distribution and properties, influenced by factors like river discharge, coastal upwelling, and net heat flux. Absolute salinity distribution showed less saline river runoff water constrained to the coastal region around the Doce River mouth and eventually in the coastal North Sector due to increased continental discharge associated with reversal southerly winds. Winter is an exception to the conservative temperature and absolute salinity distribution due to the homogeneity of cold column water and the lower input of freshwater. Particularly noteworthy is the seasonal variability observed in the River Sector, where the influence of freshwater discharge from the Doce River significantly impacts water masses distribution. CW occurrence follows the distribution of absolute salinity and the area affected by the river plume, TW is associated with the Brazil Current, and SACW occurs over the continental shelf throughout the year (despite the weak thermal gradient during the winter). At the surface, TW prevails at all sectors beyond the river influence during the autumn and past the 30 m-isobath in the remaining seasons due to upwelled waters. This study provides valuable insights into the complex interactions shaping the oceanographic characteristics of the ESCS, highlighting the importance of considering seasonal variability in understanding coastal marine ecosystems.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"289 ","pages":"Article 105462"},"PeriodicalIF":2.1,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143714592","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}

引用次数: 0

Wave influence on water circulation and self-purification ability in a semi-enclosed sea

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-03-20 DOI: 10.1016/j.csr.2025.105461

Fengze Zhao , Yuanyi Li , Dekui Yuan , Kok Weng Tan , Jian Sun

Owing to significant variation in waves, studying the effects of waves on water exchange in semi-enclosed seas is challenging, and current knowledge on this subject is insufficient, which hinders effective management of coastal seas. In this study, wave-current coupled and water age models were established to investigate the influence of waves on water exchange in the Bohai Sea, China. The results show that waves do not affect basin-scale circulation in the Bohai Sea, and their effects on water exchange are restricted to nearshore regions, especially in estuaries with subaqueous deltas. Wave-induced age variation is around 5 %, peaking at 16 % nearshore. The wave effects on basin-scale water exchange are an order of magnitude smaller than those induced by winds, yet they govern the exchange process near the Yellow River Estuary. Analysis of age distributions with and without waves indicates that wind fetch and topographic conditions are important factors in determining the wave influence on currents. Wind and storm statistics suggest that north and northeast winds are dominant. Under these conditions, the nearshore regions in the south of the Bohai Sea and downwind areas experience strong wave forces. Due to drastic depth variations at the edges of subaqueous deltas, waves induce a strong longshore current flowing westward into Laizhou Bay, with the wave influence extending nearly 100 km.

{"title":"Wave influence on water circulation and self-purification ability in a semi-enclosed sea","authors":"Fengze Zhao , Yuanyi Li , Dekui Yuan , Kok Weng Tan , Jian Sun","doi":"10.1016/j.csr.2025.105461","DOIUrl":"10.1016/j.csr.2025.105461","url":null,"abstract":"<div><div>Owing to significant variation in waves, studying the effects of waves on water exchange in semi-enclosed seas is challenging, and current knowledge on this subject is insufficient, which hinders effective management of coastal seas. In this study, wave-current coupled and water age models were established to investigate the influence of waves on water exchange in the Bohai Sea, China. The results show that waves do not affect basin-scale circulation in the Bohai Sea, and their effects on water exchange are restricted to nearshore regions, especially in estuaries with subaqueous deltas. Wave-induced age variation is around 5 %, peaking at 16 % nearshore. The wave effects on basin-scale water exchange are an order of magnitude smaller than those induced by winds, yet they govern the exchange process near the Yellow River Estuary. Analysis of age distributions with and without waves indicates that wind fetch and topographic conditions are important factors in determining the wave influence on currents. Wind and storm statistics suggest that north and northeast winds are dominant. Under these conditions, the nearshore regions in the south of the Bohai Sea and downwind areas experience strong wave forces. Due to drastic depth variations at the edges of subaqueous deltas, waves induce a strong longshore current flowing westward into Laizhou Bay, with the wave influence extending nearly 100 km.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"289 ","pages":"Article 105461"},"PeriodicalIF":2.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705407","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}

引用次数: 0

Assessment of eutrophication in a Ramsar site (Akyatan Lagoon) in the Northeastern Mediterranean Sea

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-03-20 DOI: 10.1016/j.csr.2025.105465

Nahit Soner Börekçi, İsmail Akçay, Özgür Özbay, Mehmet Tahir Alp

Coastal lagoons are transitional zones between riverine and marine systems where nutrients and contaminants often accumulate in these aquatic environments. In the present study, physical and biochemical data were obtained from the five stations between January and December 2022 for the determination of trophic status in the Akyatan Lagoon. The study results indicated the values of physical and eutrophication-related parameters displayed spatial and temporal variability. The trophic status of Akyatan Lagoon was determined by using two multi-metric classification tools as Trophic index (TRIX) and the Trophic status index (TSI). The calculated TRIX values ranged from 4.88 to 7.90 whilst the TSI values varied between 50.0 and 77.4. The strong and positive correlations between the TRIX and TSI values with their high values strongly suggested hypereutrophic conditions in the ecologically and economically important Akyatan Lagoon caused by contaminated Seyhan River inflows due to terrestrial nutrients and organic matter inputs.

沿海泻湖是河流和海洋系统之间的过渡地带，营养物质和污染物经常在这些水生环境中积累。本研究获取了 2022 年 1 月至 12 月期间五个站点的物理和生物化学数据，以确定阿亚坦泻湖的营养状态。研究结果表明，物理和富营养化相关参数的值具有时空变异性。阿亚坦泻湖的营养状况是通过营养指数（TRIX）和营养状态指数（TSI）这两种多指标分类工具确定的。计算得出的 TRIX 值介于 4.88 到 7.90 之间，而 TSI 值介于 50.0 到 77.4 之间。TRIX 值和 TSI 值之间的强正相关性及其高值有力地表明，由于陆地营养物质和有机物质的输入，塞罕河流入的污染造成了生态和经济上重要的阿亚坦泻湖的高富营养化状况。

引用次数: 0

Distribution of rare earth elements and their signatures from the Mackenzie River delta to the abyssal Arctic Ocean

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-03-19 DOI: 10.1016/j.csr.2025.105464

Thomas Bossé-Demers , Charles Gobeil , Bennet Juhls , Martine Lizotte , Michael Fritz , Lisa Bröder , Atsushi Matsuoka , Santiago Mareque , Raoul-Marie Couture

The Mackenzie River is North America's largest contributor of freshwater and sediment to the Arctic Ocean. Here, we evaluate the potential of rare earth elements (REE) as tracers of its sediment sources and fate, from the river mouth to the deep Arctic Ocean. We collected sediment cores from 21 sites, from the delta to the marine shelves, slopes and basins and measured the spatial and down-core distribution of total, leached and residual REE concentrations. Our results show that the proportion of leached REE is highest in the delta. This proportion decreases with distance from the river, suggesting mixing with other sediment sources, REE loss to the residual phase, or REE scavenging via adsorption and complexation in coastal waters. Normalized REE concentrations plotted against their atomic number provide regional signatures. The leached REE signatures indicate medium REE enrichment in the Mackenzie Delta, an enrichment that diminishes with distance from the delta. We then used a similarity index (SI) to investigate the divergence amongst REE signatures, with riverine and deep marine basin values as endmembers for the calculation. Our results highlight the influence of the Mackenzie Region sediments on the Beaufort Sea margin. Overall, our findings demonstrate that REE are relevant tracers for identifying sediment sources and that tracking REE distribution from the delta to the deep Arctic Ocean offers additional insights into sediment transport mechanisms.

{"title":"Distribution of rare earth elements and their signatures from the Mackenzie River delta to the abyssal Arctic Ocean","authors":"Thomas Bossé-Demers , Charles Gobeil , Bennet Juhls , Martine Lizotte , Michael Fritz , Lisa Bröder , Atsushi Matsuoka , Santiago Mareque , Raoul-Marie Couture","doi":"10.1016/j.csr.2025.105464","DOIUrl":"10.1016/j.csr.2025.105464","url":null,"abstract":"<div><div>The Mackenzie River is North America's largest contributor of freshwater and sediment to the Arctic Ocean. Here, we evaluate the potential of rare earth elements (REE) as tracers of its sediment sources and fate, from the river mouth to the deep Arctic Ocean. We collected sediment cores from 21 sites, from the delta to the marine shelves, slopes and basins and measured the spatial and down-core distribution of total, leached and residual REE concentrations. Our results show that the proportion of leached REE is highest in the delta. This proportion decreases with distance from the river, suggesting mixing with other sediment sources, REE loss to the residual phase, or REE scavenging via adsorption and complexation in coastal waters. Normalized REE concentrations plotted against their atomic number provide regional signatures. The leached REE signatures indicate medium REE enrichment in the Mackenzie Delta, an enrichment that diminishes with distance from the delta. We then used a similarity index (SI) to investigate the divergence amongst REE signatures, with riverine and deep marine basin values as endmembers for the calculation. Our results highlight the influence of the Mackenzie Region sediments on the Beaufort Sea margin. Overall, our findings demonstrate that REE are relevant tracers for identifying sediment sources and that tracking REE distribution from the delta to the deep Arctic Ocean offers additional insights into sediment transport mechanisms.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"289 ","pages":"Article 105464"},"PeriodicalIF":2.1,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spatial variation of marine primary productivity over ridge and trough: A case study in the East China Sea

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research

Pub Date : 2025-03-17 DOI: 10.1016/j.csr.2025.105463

Lu Zhang , Lulu Qiao , Ze Wang , Guangxue Li , Nan Wang , Yi Zhong , Yang Zhang

Tidal sand ridges are widespread in continental shelves and have attracted much attention due to their effects on ecology, geochemistry, and hydrodynamics. Typical tidal sand ridges are widely distributed throughout the East China Sea (ECS). Previous studies proposed that marine primary productivity (MPP) displays different spatial variations in ridges and troughs. Chlorophyll-a (Chl-a) and total organic carbon (TOC) are effective proxies for MPP. This study examined the influence of topography on MPP. The data analyzed included the Chl-a product from Himawari-9 and TOC and stable organic carbon isotopic compositions from surface samples in the ECS. Our results demonstrate that Chl-a displays an alternating pattern of significant fluctuations in the ECS. Chl-a concentrations in the ridge were higher than those in the trough and exhibited different characteristics at the surface and bottom of the water column. Biogeochemical parameters showed significant differences between ridges and troughs. Suspended particulate matter (SPM) and median particle size (D₅₀) in the ridges were finer than those in the troughs, indicating that fine particulates are beneficial for the enrichment and adsorption of organic carbon, which is consistent with TOC data. The C/N and δ¹³C data indicate that the organic matter in our study area originates from terrestrial and marine sources. According to the N/C calculation results, the proportion of marine organic carbon is higher on the ridge. Moreover, the temperature and nutrients, as the dominant factors affecting MPP, appear to vary in ridges and troughs. Understanding the effects of topography is important for clarifying the distribution of phytoplankton and predicting marine biological disasters.

{"title":"Spatial variation of marine primary productivity over ridge and trough: A case study in the East China Sea","authors":"Lu Zhang , Lulu Qiao , Ze Wang , Guangxue Li , Nan Wang , Yi Zhong , Yang Zhang","doi":"10.1016/j.csr.2025.105463","DOIUrl":"10.1016/j.csr.2025.105463","url":null,"abstract":"<div><div>Tidal sand ridges are widespread in continental shelves and have attracted much attention due to their effects on ecology, geochemistry, and hydrodynamics. Typical tidal sand ridges are widely distributed throughout the East China Sea (ECS). Previous studies proposed that marine primary productivity (MPP) displays different spatial variations in ridges and troughs. Chlorophyll-a (Chl-a) and total organic carbon (TOC) are effective proxies for MPP. This study examined the influence of topography on MPP. The data analyzed included the Chl-a product from Himawari-9 and TOC and stable organic carbon isotopic compositions from surface samples in the ECS. Our results demonstrate that Chl-a displays an alternating pattern of significant fluctuations in the ECS. Chl-a concentrations in the ridge were higher than those in the trough and exhibited different characteristics at the surface and bottom of the water column. Biogeochemical parameters showed significant differences between ridges and troughs. Suspended particulate matter (SPM) and median particle size (D<sub>50</sub>) in the ridges were finer than those in the troughs, indicating that fine particulates are beneficial for the enrichment and adsorption of organic carbon, which is consistent with TOC data. The C/N and δ<sup>13</sup>C data indicate that the organic matter in our study area originates from terrestrial and marine sources. According to the N/C calculation results, the proportion of marine organic carbon is higher on the ridge. Moreover, the temperature and nutrients, as the dominant factors affecting MPP, appear to vary in ridges and troughs. Understanding the effects of topography is important for clarifying the distribution of phytoplankton and predicting marine biological disasters.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"289 ","pages":"Article 105463"},"PeriodicalIF":2.1,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685204","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}

引用次数: 0