Pub Date : 2025-09-12DOI: 10.1016/j.csr.2025.105569
Bernd Schneider
<div><div>The alkalinity (A<sub>T</sub>) of the brackish water in the Baltic Sea is the product of an oceanic contribution and a contribution comprising inputs from rivers and internal sources. This non-oceanic fraction (A<sub>T</sub><sup>fresh</sup>) can be quantified by subtracting the salinity dependent oceanic A<sub>T</sub> from the measured A<sub>T</sub> and dividing the result by the freshwater fraction.</div><div><span><math><mrow><msubsup><mi>A</mi><mi>T</mi><mrow><mi>f</mi><mi>r</mi><mi>e</mi><mi>s</mi><mi>h</mi></mrow></msubsup><mo>=</mo><mrow><mo>(</mo><mrow><msub><mi>A</mi><mi>T</mi></msub><mo>−</mo><msubsup><mi>A</mi><mi>T</mi><mrow><mi>o</mi><mi>c</mi></mrow></msubsup><mo>∗</mo><mfrac><mi>S</mi><msup><mi>S</mi><mrow><mi>o</mi><mi>c</mi></mrow></msup></mfrac></mrow><mo>)</mo></mrow><mo>/</mo><mrow><mo>(</mo><mrow><mn>1</mn><mo>−</mo><mfrac><mi>S</mi><msup><mi>S</mi><mrow><mi>o</mi><mi>c</mi></mrow></msup></mfrac></mrow><mo>)</mo></mrow></mrow></math></span>, where S<sup>oc</sup> is the salinity and A<sub>T</sub><sup>oc</sup> the A<sub>T</sub> of inflowing ocean water. A<sub>T</sub><sup>fresh</sup> is thus the concentration of A<sub>T</sub> in the freshwater fraction of the Baltic Sea. The use of A<sub>T</sub><sup>fresh</sup> facilitates a simplified and transparent statistical treatment of A<sub>T</sub> data and straightforward budget calculations. Furthermore, trends in A<sub>T</sub><sup>fresh</sup> directly reflect changes in A<sub>T</sub> inputs by river water and/or internal sources.</div><div>The monthly surface water A<sub>T</sub> data (Swedish National Monitoring Programme, SMHI) during 1995–2024 at a station in the transition to the North Atlantic and at two stations in the Baltic Proper did not reveal a continuous A<sub>T</sub><sup>fresh</sup> trend, but were characterized by an interim A<sub>T</sub><sup>fresh</sup> increase during 2004–2016/17. In the central Baltic Proper the A<sub>T</sub><sup>fresh</sup> increase rate was 7.4 (μmol/kg)/yr which corresponded to 5.8 (μmol/kg)/yr for A<sub>T</sub> at a salinity of 7.1. The limited amount of A<sub>T</sub><sup>fresh</sup> data after the termination of the interim trend did not allow conclusions about the cause for the trend which could be a temporarily limited A<sub>T</sub> input event or the increase of an existing permanent A<sub>T</sub> source. In the latter case the interim trend of A<sub>T</sub><sup>fresh</sup> represents the transition towards a new steady state at an elevated A<sub>T</sub><sup>fresh</sup> level.</div><div>A<sub>T</sub><sup>fresh</sup> data for the Gulf of Bothnia for the period 2009–2024 were characterised by a distinct minimum in the middle of the measurement period, without evidence of an overall trend. Our study shows that this A<sub>T</sub><sup>fresh</sup> pattern in the gulf was due to the variations in A<sub>T</sub><sup>fresh</sup> inputs resulting from water exchange with the Baltic Proper, which mainly controlled the abundance and trends of A<su
{"title":"Alkalinity increase in the Baltic Sea: An episode or the development of a new steady state?","authors":"Bernd Schneider","doi":"10.1016/j.csr.2025.105569","DOIUrl":"10.1016/j.csr.2025.105569","url":null,"abstract":"<div><div>The alkalinity (A<sub>T</sub>) of the brackish water in the Baltic Sea is the product of an oceanic contribution and a contribution comprising inputs from rivers and internal sources. This non-oceanic fraction (A<sub>T</sub><sup>fresh</sup>) can be quantified by subtracting the salinity dependent oceanic A<sub>T</sub> from the measured A<sub>T</sub> and dividing the result by the freshwater fraction.</div><div><span><math><mrow><msubsup><mi>A</mi><mi>T</mi><mrow><mi>f</mi><mi>r</mi><mi>e</mi><mi>s</mi><mi>h</mi></mrow></msubsup><mo>=</mo><mrow><mo>(</mo><mrow><msub><mi>A</mi><mi>T</mi></msub><mo>−</mo><msubsup><mi>A</mi><mi>T</mi><mrow><mi>o</mi><mi>c</mi></mrow></msubsup><mo>∗</mo><mfrac><mi>S</mi><msup><mi>S</mi><mrow><mi>o</mi><mi>c</mi></mrow></msup></mfrac></mrow><mo>)</mo></mrow><mo>/</mo><mrow><mo>(</mo><mrow><mn>1</mn><mo>−</mo><mfrac><mi>S</mi><msup><mi>S</mi><mrow><mi>o</mi><mi>c</mi></mrow></msup></mfrac></mrow><mo>)</mo></mrow></mrow></math></span>, where S<sup>oc</sup> is the salinity and A<sub>T</sub><sup>oc</sup> the A<sub>T</sub> of inflowing ocean water. A<sub>T</sub><sup>fresh</sup> is thus the concentration of A<sub>T</sub> in the freshwater fraction of the Baltic Sea. The use of A<sub>T</sub><sup>fresh</sup> facilitates a simplified and transparent statistical treatment of A<sub>T</sub> data and straightforward budget calculations. Furthermore, trends in A<sub>T</sub><sup>fresh</sup> directly reflect changes in A<sub>T</sub> inputs by river water and/or internal sources.</div><div>The monthly surface water A<sub>T</sub> data (Swedish National Monitoring Programme, SMHI) during 1995–2024 at a station in the transition to the North Atlantic and at two stations in the Baltic Proper did not reveal a continuous A<sub>T</sub><sup>fresh</sup> trend, but were characterized by an interim A<sub>T</sub><sup>fresh</sup> increase during 2004–2016/17. In the central Baltic Proper the A<sub>T</sub><sup>fresh</sup> increase rate was 7.4 (μmol/kg)/yr which corresponded to 5.8 (μmol/kg)/yr for A<sub>T</sub> at a salinity of 7.1. The limited amount of A<sub>T</sub><sup>fresh</sup> data after the termination of the interim trend did not allow conclusions about the cause for the trend which could be a temporarily limited A<sub>T</sub> input event or the increase of an existing permanent A<sub>T</sub> source. In the latter case the interim trend of A<sub>T</sub><sup>fresh</sup> represents the transition towards a new steady state at an elevated A<sub>T</sub><sup>fresh</sup> level.</div><div>A<sub>T</sub><sup>fresh</sup> data for the Gulf of Bothnia for the period 2009–2024 were characterised by a distinct minimum in the middle of the measurement period, without evidence of an overall trend. Our study shows that this A<sub>T</sub><sup>fresh</sup> pattern in the gulf was due to the variations in A<sub>T</sub><sup>fresh</sup> inputs resulting from water exchange with the Baltic Proper, which mainly controlled the abundance and trends of A<su","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105569"},"PeriodicalIF":2.2,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096246","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 : 2025-09-11DOI: 10.1016/j.csr.2025.105570
Jiajia Dai , Jinming Song , Lilian Wen , Jun Ma , Huamao Yuan , Xuegang Li , Liqin Duan , Qidong Wang
Sulfonamides (SAs), widely used in human and veterinary medicine, enter the environment through metabolism and accumulate in marine ecosystems, affecting both marine ecosystems and human health. However, there is a lack of systematic research in China regarding the relationship between the usage inputs of SAs and their marine fate. This study presented a comprehensive analysis of data regarding SAs in the marginal seas of China and the usage of SAs from 2009 to 2020 what we can collect, focusing on the distribution and fate of SAs in China's marginal seas. Results supported by restrictive data indicated 22 types of SAs in seawater and 17 in sediments, with sulfamethoxazole and trimethoprim being the two primary SAs. Total SAs concentration in seawater ranged from 0.12 ng/L to 309.71 ng/L, while in sediments it ranged from 0.07 ng/g to 360.4 ng/g, with the Bohai Sea being the most severely polluted marine area by SAs in China. SAs residues varied significantly by year, ranging from 3 tons to 242 tons in the Bohai Sea and from 7 tons to 316 tons in the Yellow Sea. It is noteworthy that the residues of SAs in both the Bohai Sea and Yellow Sea have markedly decreased in recent years, reflecting reduced pollution levels likely attributed to factors such as reduced usage of SAs due to national regulatory measures. This study holds significant scientific value for systematically understanding the status of SAs in China's marginal seas, as well as for formulating strategies for the use, emission, and pollution management of emerging contaminants including SAs.
{"title":"Sulfonamides as emerging contaminants in China's marginal seas: Distribution, Usage, and Residues","authors":"Jiajia Dai , Jinming Song , Lilian Wen , Jun Ma , Huamao Yuan , Xuegang Li , Liqin Duan , Qidong Wang","doi":"10.1016/j.csr.2025.105570","DOIUrl":"10.1016/j.csr.2025.105570","url":null,"abstract":"<div><div>Sulfonamides (SAs), widely used in human and veterinary medicine, enter the environment through metabolism and accumulate in marine ecosystems, affecting both marine ecosystems and human health. However, there is a lack of systematic research in China regarding the relationship between the usage inputs of SAs and their marine fate. This study presented a comprehensive analysis of data regarding SAs in the marginal seas of China and the usage of SAs from 2009 to 2020 what we can collect, focusing on the distribution and fate of SAs in China's marginal seas. Results supported by restrictive data indicated 22 types of SAs in seawater and 17 in sediments, with sulfamethoxazole and trimethoprim being the two primary SAs. Total SAs concentration in seawater ranged from 0.12 ng/L to 309.71 ng/L, while in sediments it ranged from 0.07 ng/g to 360.4 ng/g, with the Bohai Sea being the most severely polluted marine area by SAs in China. SAs residues varied significantly by year, ranging from 3 tons to 242 tons in the Bohai Sea and from 7 tons to 316 tons in the Yellow Sea. It is noteworthy that the residues of SAs in both the Bohai Sea and Yellow Sea have markedly decreased in recent years, reflecting reduced pollution levels likely attributed to factors such as reduced usage of SAs due to national regulatory measures. This study holds significant scientific value for systematically understanding the status of SAs in China's marginal seas, as well as for formulating strategies for the use, emission, and pollution management of emerging contaminants including SAs.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105570"},"PeriodicalIF":2.2,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145059912","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 : 2025-09-09DOI: 10.1016/j.csr.2025.105567
Sajjad Feizabadi , Sarah M. Brannum , Masoud Ghodsian , Mohammad Nabi Allahdadi , Nazanin Chaichitehrani
Storm surge barriers (SSB), as engineering measures within broader coastal risk mitigation strategies, have been implemented or proposed in estuaries around the world. During non-storm periods, some parts of barriers restrict cross-flow area which alters water exchange and estuarine hydrodynamics. This study investigates the effects of permanent barrier infrastructure on the hydrodynamics of the Hudson-Raritan Estuary (HRE), a partially mixed estuary characterized by a complex geometry that includes bays connected by tidal straits and multiple tidal inlets. Our research employs a three-dimensional hydrodynamic model (EFDC) to focus on five distinct scenarios developed by the United States Army Corps of Engineers (USACE), exploring aspects of these systems that have not been examined previously. The implementation of SSBs leads to increased salinity content, intrusion, and stratification in tributaries and a decrease on the landward side of the barrier, particularly when key pathways for water exchange are obstructed. Depending on the specific configurations of the SSBs, salinity variations in different regions range from an increase of 12 % to a decrease of 10 %. Results indicate a reduction in both semi-diurnal and diurnal tidal signals across the HRE, significantly affecting the energy partitioning. For instance, an SSB at the Lower Bay entrance reduces the semi-diurnal component of the total energy budget from 73 % in the base case to 46 %, while increasing the subtidal component's contribution from 23 % to 50 %. Additionally, SSBs alter the residual currents, induce eddy formations, and amplify currents across both surface and bottom layers. The response of residence times to SSB configurations varies spatially across the domain; on average, residence time in the HRE rises between 13 % and 67 % across the different SSB configuration scenarios compared to the base case, which has a spatially averaged residence time of approximately 15.9 days. The impact of SSBs on estuarine hydrodynamics strongly depends on their specific location and configuration. This study provides a framework for understanding the potential impacts of any proposed surge barrier systems and enhances our comprehension of their ecological and environmental effects.
{"title":"Evaluating the hydrodynamic and transport responses to storm surge barriers in a partially mixed Estuary: A case study of the Hudson–Raritan estuary","authors":"Sajjad Feizabadi , Sarah M. Brannum , Masoud Ghodsian , Mohammad Nabi Allahdadi , Nazanin Chaichitehrani","doi":"10.1016/j.csr.2025.105567","DOIUrl":"10.1016/j.csr.2025.105567","url":null,"abstract":"<div><div>Storm surge barriers (SSB), as engineering measures within broader coastal risk mitigation strategies, have been implemented or proposed in estuaries around the world. During non-storm periods, some parts of barriers restrict cross-flow area which alters water exchange and estuarine hydrodynamics. This study investigates the effects of permanent barrier infrastructure on the hydrodynamics of the Hudson-Raritan Estuary (HRE), a partially mixed estuary characterized by a complex geometry that includes bays connected by tidal straits and multiple tidal inlets. Our research employs a three-dimensional hydrodynamic model (EFDC) to focus on five distinct scenarios developed by the United States Army Corps of Engineers (USACE), exploring aspects of these systems that have not been examined previously. The implementation of SSBs leads to increased salinity content, intrusion, and stratification in tributaries and a decrease on the landward side of the barrier, particularly when key pathways for water exchange are obstructed. Depending on the specific configurations of the SSBs, salinity variations in different regions range from an increase of 12 % to a decrease of 10 %. Results indicate a reduction in both semi-diurnal and diurnal tidal signals across the HRE, significantly affecting the energy partitioning. For instance, an SSB at the Lower Bay entrance reduces the semi-diurnal component of the total energy budget from 73 % in the base case to 46 %, while increasing the subtidal component's contribution from 23 % to 50 %. Additionally, SSBs alter the residual currents, induce eddy formations, and amplify currents across both surface and bottom layers. The response of residence times to SSB configurations varies spatially across the domain; on average, residence time in the HRE rises between 13 % and 67 % across the different SSB configuration scenarios compared to the base case, which has a spatially averaged residence time of approximately 15.9 days. The impact of SSBs on estuarine hydrodynamics strongly depends on their specific location and configuration. This study provides a framework for understanding the potential impacts of any proposed surge barrier systems and enhances our comprehension of their ecological and environmental effects.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105567"},"PeriodicalIF":2.2,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049679","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 : 2025-09-08DOI: 10.1016/j.csr.2025.105564
Jithendra Raju Nadimpalli , Mihir Kumar Dash , Ibrahim Hoteit
The synthetic aperture radar (SAR) image acquired on 23 April 2004 at 03:33 UTC by the Envisat shows the separation of short wavelength internal waves from the westward propagating mode-1 ISW generating from a shallow ridge connecting Batti Malv and Chowra Islands (SBM) of the northern Nicobar Islands, India. To investigate the presence of tailless mode-1 ISWs, several other SAR images near the SBM are analyzed. A particular SAR image captured on 12 October 2007 at 15:53 UTC reveals two different higher-mode ISWs in the path of the mode-1 ISW. Fitting the locations of the ISW signatures onto a time-distance curve shows that one of the higher modes is generated locally, while others are generated from SBM. Using simulations of a nonhydrostatic numerical model SUNTANS, we show that the SBM generated westward propagating mode-1 ISW overtakes the locally generated mode-3 ISW and a mode-2 ISW formed over the SBM in the previous tidal cycle. It is shown that the interaction process of the first mode with higher modes results in the formation of short internal waves trailing behind higher mode waves, pertaining to the resonance between the tail of mode-1 ISW and the higher mode solitary wave. Hence, close to a spring tide, with a combination of SAR images and numerical simulations, we show the dynamical process of westward propagating mode-1 ISW from SBM with the higher modes.
{"title":"On the interaction of mode-1 Internal Solitary Wave with higher modes to the west of northern Nicobar Islands","authors":"Jithendra Raju Nadimpalli , Mihir Kumar Dash , Ibrahim Hoteit","doi":"10.1016/j.csr.2025.105564","DOIUrl":"10.1016/j.csr.2025.105564","url":null,"abstract":"<div><div>The synthetic aperture radar (SAR) image acquired on 23 April 2004 at 03:33 UTC by the Envisat shows the separation of short wavelength internal waves from the westward propagating mode-1 ISW generating from a shallow ridge connecting Batti Malv and Chowra Islands (SBM) of the northern Nicobar Islands, India. To investigate the presence of tailless mode-1 ISWs, several other SAR images near the SBM are analyzed. A particular SAR image captured on 12 October 2007 at 15:53 UTC reveals two different higher-mode ISWs in the path of the mode-1 ISW. Fitting the locations of the ISW signatures onto a time-distance curve shows that one of the higher modes is generated locally, while others are generated from SBM. Using simulations of a nonhydrostatic numerical model SUNTANS, we show that the SBM generated westward propagating mode-1 ISW overtakes the locally generated mode-3 ISW and a mode-2 ISW formed over the SBM in the previous tidal cycle. It is shown that the interaction process of the first mode with higher modes results in the formation of short internal waves trailing behind higher mode waves, pertaining to the resonance between the tail of mode-1 ISW and the higher mode solitary wave. Hence, close to a spring tide, with a combination of SAR images and numerical simulations, we show the dynamical process of westward propagating mode-1 ISW from SBM with the higher modes.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105564"},"PeriodicalIF":2.2,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049678","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 : 2025-09-02DOI: 10.1016/j.csr.2025.105565
M.S. Filmer , P.L. Woodworth , S.D.P. Williams , S.J. Claessens
We conduct a study to estimate uncertainties in tidal constants from M2, S2, N2, K1, O1, Q1 and related K2, P1, 2N2 constituents from 35-day tide gauge records in the northern Australia and Papua New Guinea regions. The motivation for this study stems from the availability of ∼300 short tide gauge records (most ∼ 30 days long) in these regions, but their accuracy for tidal studies is not clear. We simulate the 35-day uncertainties by dividing a selected set of 14 long tide gauge records (19-years where available) from the GESLA3 data set into consecutive 35-day sections. Amplitudes and phase lags computed from each long record are treated as the ‘true’ values, from which we compute and analyse inference information for the short records. Comparison of empirical amplitude ratios and phase lag differences with the relationships from the Equilibrium tide show significant differences in both amplitude and phase lag in some constituents and locations. We also compare inference information derived from the FES2022b ocean tide model, which suggests that such models could be used in this way in some instances. Empirical uncertainties in the 35-day records were no more than 0.045 m with maximum errors reaching 0.093 m. The largest 35-day errors appeared in the K1 constituent, mostly in the Torres Strait and northwest Australia. Empirical inference information showed improvement on the Equilibrium assumption for S2 and K1 reference constituents and related constituents K2, 2N2 and P1, demonstrating that the latter can be accurately derived from short records with accurate inference information.
{"title":"Analysis of the uncertainties in tidal constants obtained from short tide gauge records and their value for tidal studies","authors":"M.S. Filmer , P.L. Woodworth , S.D.P. Williams , S.J. Claessens","doi":"10.1016/j.csr.2025.105565","DOIUrl":"10.1016/j.csr.2025.105565","url":null,"abstract":"<div><div>We conduct a study to estimate uncertainties in tidal constants from M2, S2, N2, K1, O1, Q1 and related K2, P1, 2N2 constituents from 35-day tide gauge records in the northern Australia and Papua New Guinea regions. The motivation for this study stems from the availability of ∼300 short tide gauge records (most ∼ 30 days long) in these regions, but their accuracy for tidal studies is not clear. We simulate the 35-day uncertainties by dividing a selected set of 14 long tide gauge records (19-years where available) from the GESLA3 data set into consecutive 35-day sections. Amplitudes and phase lags computed from each long record are treated as the ‘true’ values, from which we compute and analyse inference information for the short records. Comparison of empirical amplitude ratios and phase lag differences with the relationships from the Equilibrium tide show significant differences in both amplitude and phase lag in some constituents and locations. We also compare inference information derived from the FES2022b ocean tide model, which suggests that such models could be used in this way in some instances. Empirical uncertainties in the 35-day records were no more than 0.045 m with maximum errors reaching 0.093 m. The largest 35-day errors appeared in the K1 constituent, mostly in the Torres Strait and northwest Australia. Empirical inference information showed improvement on the Equilibrium assumption for S2 and K1 reference constituents and related constituents K2, 2N2 and P1, demonstrating that the latter can be accurately derived from short records with accurate inference information.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105565"},"PeriodicalIF":2.2,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096249","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 : 2025-09-02DOI: 10.1016/j.csr.2025.105561
Jorge M. Magalhaes , Martin J. Coubard , José C.B. da Silva , Maarten C. Buijsman , Ana Isabel Santos , Ana Amorim , Paulo B. Oliveira
Wind and Internal Solitary Waves (ISWs) are well-known to mix the ocean's surface and inner stratification, but their combined effects appear to have not yet been investigated. A large ensemble of ISWs measured off the Portuguese Coast reveals that wind and ISWs may combine to increase turbulence and mixing beyond the linear combination of their individual contributions. It is found that low bulk Richardson numbers () and temperature inversions increase respectively by nearly four-fold and an order of magnitude, when comparing ISWs propagating under high and low-wind regimes. Furthermore, depth ranges where associated with ISWs propagating with high winds are observed to extend at least between unperturbed thermocline and intermediate depths. Understanding how turbulence and mixing from ISWs and wind combine may have important implications ranging from parametrizations in ocean models to our understanding of biogeochemical processes modulated by diapycnal mixing.
{"title":"Shear instabilities in Internal Solitary Waves under high and low-wind regimes","authors":"Jorge M. Magalhaes , Martin J. Coubard , José C.B. da Silva , Maarten C. Buijsman , Ana Isabel Santos , Ana Amorim , Paulo B. Oliveira","doi":"10.1016/j.csr.2025.105561","DOIUrl":"10.1016/j.csr.2025.105561","url":null,"abstract":"<div><div>Wind and Internal Solitary Waves (ISWs) are well-known to mix the ocean's surface and inner stratification, but their combined effects appear to have not yet been investigated. A large ensemble of ISWs measured off the Portuguese Coast reveals that wind and ISWs may combine to increase turbulence and mixing beyond the linear combination of their individual contributions. It is found that low bulk Richardson numbers (<span><math><mrow><mi>R</mi><mi>i</mi><mo><</mo><mfrac><mn>1</mn><mn>4</mn></mfrac></mrow></math></span>) and temperature inversions increase respectively by nearly four-fold and an order of magnitude, when comparing ISWs propagating under high and low-wind regimes. Furthermore, depth ranges where <span><math><mrow><mi>R</mi><mi>i</mi><mo><</mo><mfrac><mn>1</mn><mn>4</mn></mfrac></mrow></math></span> associated with ISWs propagating with high winds are observed to extend at least between unperturbed thermocline and intermediate depths. Understanding how turbulence and mixing from ISWs and wind combine may have important implications ranging from parametrizations in ocean models to our understanding of biogeochemical processes modulated by diapycnal mixing.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105561"},"PeriodicalIF":2.2,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027203","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 : 2025-09-02DOI: 10.1016/j.csr.2025.105560
Jonathan Rogerson , Jennifer Veitch , Samantha Siedlecki , Sarah Fawcett
Mesoscale fronts are ubiquitous features in all Eastern Boundary Upwelling Systems and are the result of prominent sea surface temperature (SST) gradients and baroclinic jets. Their seasonal variability and presence can impact the horizontal mixing patterns of particles and nutrients. Here, we examine the role of alongshore fronts in shaping the seasonal patterns of cross-shore mixing, residence times, and surface particle transport along the shelf region of the Southern Benguela Upwelling System. Using a numerical ocean model together with a front-detection algorithm, Lagrangian particle tracking, and Finite Time Lyapunov Exponents, we investigate mesoscale frontal variability. In summer, fronts are typically long and continuous alongshore features that are defined by strong SST gradients and associated with prominent Lagrangian Coherent Structures (LCSs). These fronts can act as cohesive barriers that limit cross-shore mixing and offshore advection of particles. In winter, fronts are generally found further offshore and are more filamentous and numerous compared to summer. Furthermore, they are defined by weaker SST frontal gradients and shorter frontal lengths. Fronts in winter are not associated with any obvious LCSs, which implies that particles and material experience greater rates of dispersion and cross-shore mixing. Lagrangian float experiments confirm this and show surface particle trajectories in winter to be more variable and chaotic compared to the more uniform patterns observed in summer. Therefore, defined alongshore fronts in summer aid in the retention of particles on the shelf. The seasonal erosion of these defined frontal features allows for greater cross-shore mixing of particles, water masses and nutrients in the upper water column during winter.
{"title":"Frontal features and mixing regimes along the shelf region of the Southern Benguela upwelling system","authors":"Jonathan Rogerson , Jennifer Veitch , Samantha Siedlecki , Sarah Fawcett","doi":"10.1016/j.csr.2025.105560","DOIUrl":"10.1016/j.csr.2025.105560","url":null,"abstract":"<div><div>Mesoscale fronts are ubiquitous features in all Eastern Boundary Upwelling Systems and are the result of prominent sea surface temperature (SST) gradients and baroclinic jets. Their seasonal variability and presence can impact the horizontal mixing patterns of particles and nutrients. Here, we examine the role of alongshore fronts in shaping the seasonal patterns of cross-shore mixing, residence times, and surface particle transport along the shelf region of the Southern Benguela Upwelling System. Using a numerical ocean model together with a front-detection algorithm, Lagrangian particle tracking, and Finite Time Lyapunov Exponents, we investigate mesoscale frontal variability. In summer, fronts are typically long and continuous alongshore features that are defined by strong SST gradients and associated with prominent Lagrangian Coherent Structures (LCSs). These fronts can act as cohesive barriers that limit cross-shore mixing and offshore advection of particles. In winter, fronts are generally found further offshore and are more filamentous and numerous compared to summer. Furthermore, they are defined by weaker SST frontal gradients and shorter frontal lengths. Fronts in winter are not associated with any obvious LCSs, which implies that particles and material experience greater rates of dispersion and cross-shore mixing. Lagrangian float experiments confirm this and show surface particle trajectories in winter to be more variable and chaotic compared to the more uniform patterns observed in summer. Therefore, defined alongshore fronts in summer aid in the retention of particles on the shelf. The seasonal erosion of these defined frontal features allows for greater cross-shore mixing of particles, water masses and nutrients in the upper water column during winter.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105560"},"PeriodicalIF":2.2,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096248","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 : 2025-09-01DOI: 10.1016/j.csr.2025.105563
Tri Ernawati , Mennofatria Boer , Mohammad Mukhlis Kamal , Nurlisa Alias Butet , Fayakun Satria , Peter J. Mous
The Makassar Strait and adjacent waters, which is crossed by the Wallace line, has variations in bathymetry and unique ocean currents. This condition allows for genetic differences in the Malabar blood snapper (Lutjanus malabaricus) and the Goldband snapper (Pristipomoides multidens) in the strait. Specimens were collected from some landing bases in Makassar Strait and adjacent waters as part of Indonesia's Fisheries Management Area (FMA) 713 and assessed using d-loop mtDNA. Both L.malabaricus and P.multidens obtained the same sequencing results of around 400 bp with 67 and 71 of number haplotypes, respectively. The results of the polymorphism of the two species showed high genetic diversity (L.malabaricus: h = 0.9284, π = 0.0434; P.multidens: h = 0.9766, π = 0.0532). Based on differences analysis to examine the population genetic structure showed different results. L.malabaricus was identified as having no population genetic structure. On the other hand, P. multidens has significant (ΦST = 0.07010, p < 0.001) structural differences among sub-areas, the western part of the Makassar Strait, the eastern part of the Makassar Strait, and south of the Makassar Strait, Flores Sea. The different stock units need to be considered in the development of fisheries management and surveillance. Management of fish resources requires a flexible and adaptive approach, taking into account the fishery characteristics of each population and the broad ecosystems in which they occur.
望加锡海峡和华莱士线所穿过的邻近水域，在水深和独特的洋流方面都有变化。这种情况允许海峡中马拉巴尔血鲷（Lutjanus malabaricus）和金带鲷（pritipomoides multidens）的遗传差异。从印度尼西亚渔业管理区（FMA） 713的望加锡海峡和邻近水域的一些登陆基地收集标本，并使用d-环mtDNA进行评估。malabaricus和multidens的测序结果相同，分别在400 bp左右，分别有67和71个单倍型。两种植物的多态性分析结果显示：L.malabaricus: h = 0.9284, π = 0.0434； P.multidens: h = 0.9766, π = 0.0532；基于差异分析对种群遗传结构的检验显示出不同的结果。malabaricus不具有群体遗传结构。另一方面，在望加锡海峡西部、望加锡海峡东部、望加锡海峡南部、弗洛勒斯海的子区域间，多登云雀具有显著的结构差异（ΦST = 0.07010, p < 0.001）。在发展渔业管理和监测时需要考虑到不同的种群单位。鱼类资源的管理需要采取灵活和适应的办法，同时考虑到每个种群的渔业特点和它们所处的广泛生态系统。
{"title":"Genetic differentiation in populations of two snappers, Lutjanus malabaricus and Pristipomoides multidens, in the Makassar Strait and adjacent waters, Indonesia: Implications for management","authors":"Tri Ernawati , Mennofatria Boer , Mohammad Mukhlis Kamal , Nurlisa Alias Butet , Fayakun Satria , Peter J. Mous","doi":"10.1016/j.csr.2025.105563","DOIUrl":"10.1016/j.csr.2025.105563","url":null,"abstract":"<div><div>The Makassar Strait and adjacent waters, which is crossed by the Wallace line, has variations in bathymetry and unique ocean currents. This condition allows for genetic differences in the Malabar blood snapper (<em>Lutjanus malabaricus</em>) and the Goldband snapper (<em>Pristipomoides multidens</em>) in the strait. Specimens were collected from some landing bases in Makassar Strait and adjacent waters as part of Indonesia's Fisheries Management Area (FMA) 713 and assessed using d-loop mtDNA. Both <em>L.malabaricus</em> and <em>P.multidens</em> obtained the same sequencing results of around 400 bp with 67 and 71 of number haplotypes, respectively. The results of the polymorphism of the two species showed high genetic diversity (<em>L.malabaricus</em>: <em>h</em> = 0.9284, <em>π</em> = 0.0434; <em>P.multidens</em>: <em>h</em> = 0.9766, <em>π</em> = 0.0532). Based on differences analysis to examine the population genetic structure showed different results. <em>L.malabaricus</em> was identified as having no population genetic structure. On the other hand, <em>P. multidens</em> has significant (<em>Φ</em><sub><em>ST</em></sub> = 0.07010, <em>p</em> < 0.001) structural differences among sub-areas, the western part of the Makassar Strait, the eastern part of the Makassar Strait, and south of the Makassar Strait, Flores Sea. The different stock units need to be considered in the development of fisheries management and surveillance. Management of fish resources requires a flexible and adaptive approach, taking into account the fishery characteristics of each population and the broad ecosystems in which they occur.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105563"},"PeriodicalIF":2.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933128","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 : 2025-08-31DOI: 10.1016/j.csr.2025.105562
Lucy Coral Alarcón-Ortega , Nancy Ramírez-Álvarez , Félix Augusto Hernández-Guzmán , Eduardo Antonio Lozano-Hernández
Coastal lagoons are ecologically and economically important ecosystems, serving as nursery areas for marine species, providing coastal protection, and filtering pollutants. Despite their significance, these environments are increasingly exposed to various contaminants, including microplastics (MPs) and non-synthetic microfibers (NSMs), which are pervasive in ecosystems worldwide. Due to their size, they can be ingested by marine organisms and transferred to higher trophic levels, posing a risk to marine life and human health. NSMs and MPs were identified and quantified in farmed oysters (Magallana gigas) and in surface water, bottom water, and sediments from a rural coastal lagoon in Baja California, Mexico. Once the samples were collected, the organic matter was removed, filtered, and finally, the particles were separated according to their shape, color, and size. The chemical composition of the particles was analyzed using μ-FTIR-ATR. The most frequently identified polymers were cellulose, cotton, and polyester, common across all matrices. Polypropylene was predominant only in surface water samples. These findings highlight the diverse sources and potential behaviors of MPs and NSMs in the lagoon. Although the lagoon experiences low anthropogenic impact and limited runoff, it is not exempt from pollution. The detection of MPs and NSMs in water, sediment, and oysters reflects the vulnerability of coastal lagoons to pollutants. It suggests a need for continued monitoring better to understand potential implications for ecosystem and human health.
{"title":"Potential human consumption risks from microplastics and non-synthetic microfibers in cultured oysters from a low-human-impact lagoon","authors":"Lucy Coral Alarcón-Ortega , Nancy Ramírez-Álvarez , Félix Augusto Hernández-Guzmán , Eduardo Antonio Lozano-Hernández","doi":"10.1016/j.csr.2025.105562","DOIUrl":"10.1016/j.csr.2025.105562","url":null,"abstract":"<div><div>Coastal lagoons are ecologically and economically important ecosystems, serving as nursery areas for marine species, providing coastal protection, and filtering pollutants. Despite their significance, these environments are increasingly exposed to various contaminants, including microplastics (MPs) and non-synthetic microfibers (NSMs), which are pervasive in ecosystems worldwide. Due to their size, they can be ingested by marine organisms and transferred to higher trophic levels, posing a risk to marine life and human health. NSMs and MPs were identified and quantified in farmed oysters (<em>Magallana gigas</em>) and in surface water, bottom water, and sediments from a rural coastal lagoon in Baja California, Mexico. Once the samples were collected, the organic matter was removed, filtered, and finally, the particles were separated according to their shape, color, and size. The chemical composition of the particles was analyzed using μ-FTIR-ATR. The most frequently identified polymers were cellulose, cotton, and polyester, common across all matrices. Polypropylene was predominant only in surface water samples. These findings highlight the diverse sources and potential behaviors of MPs and NSMs in the lagoon. Although the lagoon experiences low anthropogenic impact and limited runoff, it is not exempt from pollution. The detection of MPs and NSMs in water, sediment, and oysters reflects the vulnerability of coastal lagoons to pollutants. It suggests a need for continued monitoring better to understand potential implications for ecosystem and human health.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105562"},"PeriodicalIF":2.2,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997308","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 : 2025-08-23DOI: 10.1016/j.csr.2025.105551
Rodrigo Zanette , Marília S. Ramos , Mario Luiz Mascagni , Antonio H.F. Klein , Leandro Farina
This study presents a comprehensive analysis of the wave climate in Babitonga Bay, Brazil, using a hybrid downscaling approach. By integrating dynamic and statistical techniques, we effectively transferred CAWCR oceanic wave reanalysis data (1979 to 2022), for a point on the continental shelf to the coastal region, focusing on the ports of São Francisco do Sul and Itapoá. The methodology included selecting representative sea states, propagating them with the SWAN wave model, and reconstructing the time series using radial basis function interpolation. Validation against observational data at three ADCP stations showed that the hybrid downscaling results more accurately captured wave parameters compared to CAWCR hindcast, particularly at shallow water stations (4–7 m depth) where the downscaled significant wave heights closely tracked measured values, highlighting the effectiveness of the downscaling approach. Furthermore, the analysis reveals a bimodal wave climate at each port, distinguishing between the persistent, operational wave conditions and less frequent but distinct swell events from a secondary direction, a critical insight for risk assessment. The study provides detailed 2D and 3D analyses of wave parameters such as significant wave height (), peak period (), and wave direction, revealing crucial insights into wave age and height dynamics in São Francisco do Sul. These findings offer valuable data for coastal management and infrastructure planning in Babitonga Bay and similar regions. The hybrid downscaling methodology presented here proves to be an efficient and reliable tool for characterizing wave climate in port regions, providing essential information for safe navigation and port operations in São Francisco do Sul and Itapoá.
{"title":"Wave climate at Babitonga Bay using hybrid downscaling","authors":"Rodrigo Zanette , Marília S. Ramos , Mario Luiz Mascagni , Antonio H.F. Klein , Leandro Farina","doi":"10.1016/j.csr.2025.105551","DOIUrl":"10.1016/j.csr.2025.105551","url":null,"abstract":"<div><div>This study presents a comprehensive analysis of the wave climate in Babitonga Bay, Brazil, using a hybrid downscaling approach. By integrating dynamic and statistical techniques, we effectively transferred CAWCR oceanic wave reanalysis data (1979 to 2022), for a point on the continental shelf to the coastal region, focusing on the ports of São Francisco do Sul and Itapoá. The methodology included selecting representative sea states, propagating them with the SWAN wave model, and reconstructing the time series using radial basis function interpolation. Validation against observational data at three ADCP stations showed that the hybrid downscaling results more accurately captured wave parameters compared to CAWCR hindcast, particularly at shallow water stations (4–7 m depth) where the downscaled significant wave heights closely tracked measured values, highlighting the effectiveness of the downscaling approach. Furthermore, the analysis reveals a bimodal wave climate at each port, distinguishing between the persistent, operational wave conditions and less frequent but distinct swell events from a secondary direction, a critical insight for risk assessment. The study provides detailed 2D and 3D analyses of wave parameters such as significant wave height (<span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>), peak period (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>), and wave direction, revealing crucial insights into wave age and height dynamics in São Francisco do Sul. These findings offer valuable data for coastal management and infrastructure planning in Babitonga Bay and similar regions. The hybrid downscaling methodology presented here proves to be an efficient and reliable tool for characterizing wave climate in port regions, providing essential information for safe navigation and port operations in São Francisco do Sul and Itapoá.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"295 ","pages":"Article 105551"},"PeriodicalIF":2.2,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903997","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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