Pub Date : 2025-02-01DOI: 10.1016/j.csr.2024.105392
İsmail Akçay , Süleyman Tuğrul , Mustafa Yücel
The coastal ecosystem of the Northeastern (NE) Mediterranean Sea has been affected by nutrient inputs originated from regional rivers and wastewater discharges. Sediment porewater nutrient fluxes into the deep waters are strongly associated with eutrophic and suboxic/anoxic conditions. There was only limited number of studies performed on the porewater and sediment biogeochemistry in the NE Mediterranean Sea having oxic conditions in the deep waters. In this study, therefore, sediment porewater nutrient (Si, N, P) and sediment organic matter biogeochemistry were studied. The study results indicated a series of redox reactions as well as remarkable contribution of porewater diffusive nutrient fluxes to the total nutrient budget in the NE Mediterranean Sea. Lower Si/N and higher N/P molar ratios in the total nutrient inputs are very likely to modify phytoplankton composition and abundance in the phosphorus deficient NE Mediterranean productive shelf waters leading to development of mesotrophic/eutrophic conditions in the NE Mediterranean Sea.
{"title":"Seafloor nutrient biogeochemistry and benthic fluxes in the Northeastern Mediterranean sea","authors":"İsmail Akçay , Süleyman Tuğrul , Mustafa Yücel","doi":"10.1016/j.csr.2024.105392","DOIUrl":"10.1016/j.csr.2024.105392","url":null,"abstract":"<div><div>The coastal ecosystem of the Northeastern (NE) Mediterranean Sea has been affected by nutrient inputs originated from regional rivers and wastewater discharges. Sediment porewater nutrient fluxes into the deep waters are strongly associated with eutrophic and suboxic/anoxic conditions. There was only limited number of studies performed on the porewater and sediment biogeochemistry in the NE Mediterranean Sea having oxic conditions in the deep waters. In this study, therefore, sediment porewater nutrient (Si, N, P) and sediment organic matter biogeochemistry were studied. The study results indicated a series of redox reactions as well as remarkable contribution of porewater diffusive nutrient fluxes to the total nutrient budget in the NE Mediterranean Sea. Lower Si/N and higher N/P molar ratios in the total nutrient inputs are very likely to modify phytoplankton composition and abundance in the phosphorus deficient NE Mediterranean productive shelf waters leading to development of mesotrophic/eutrophic conditions in the NE Mediterranean Sea.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105392"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145176","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 : 2025-02-01DOI: 10.1016/j.csr.2025.105404
Shujin Guo , Feng Wang , Qingzhen Yao , Yanqing Wang , Meiping Feng , Xiaoxia Sun
Phytoplankton carbon biomass serves as a valuable indicator of phytoplankton biomass, playing a crucial role in parameterizing ecosystem models. However, studies on phytoplankton carbon biomass have been quite limited in continental seas, providing limited references for understanding their role in the biogeochemical carbon cycle. In this study, we examined phytoplankton carbon biomass in the SYS during the spring, summer, and fall of 2018, and clarified its characteristics, distribution patterns and controlling factors. Phytoplankton carbon biomass ranged from 2.33 to 84.74 μg C/L in spring, 1.19–1454.25 μg C/L in summer, and 0.01–33.20 μg C/L in fall in the SYS. Diatoms were the most dominant group, contributing 53%, 68%, and 67% to the total phytoplankton carbon in spring, summer, and fall, respectively, followed by dinoflagellates, which contributed 46%, 31%, and 30%. The carbon biomass of diatoms and dinoflagellates exhibited quite distinct correlations with environmental factors. Diatoms exhibited stronger nutrient dependency, whereas no significant correlation was observed between dinoflagellates and nutrients, reflecting the different nutritional strategies of the two groups (strict autotrophy vs. mixotrophy). Compared to cell abundance, carbon biomass revealed a significantly higher proportion of dinoflagellate biomass in the community structure, which is primarily due to the significant interspecies variations in cell volume. Dinoflagellates tend to have larger cell volumes compared to diatoms in the SYS, leading to an underestimation of dinoflagellate proportions when using cell abundance alone. This indicates that simply using cell abundance may lead to cognitive bias in recognizing phytoplankton community structure, and taking carbon biomass into account will provide a more comprehensive understanding.
{"title":"Seasonal dynamics and environmental drivers of phytoplankton carbon biomass in the southern yellow sea","authors":"Shujin Guo , Feng Wang , Qingzhen Yao , Yanqing Wang , Meiping Feng , Xiaoxia Sun","doi":"10.1016/j.csr.2025.105404","DOIUrl":"10.1016/j.csr.2025.105404","url":null,"abstract":"<div><div>Phytoplankton carbon biomass serves as a valuable indicator of phytoplankton biomass, playing a crucial role in parameterizing ecosystem models. However, studies on phytoplankton carbon biomass have been quite limited in continental seas, providing limited references for understanding their role in the biogeochemical carbon cycle. In this study, we examined phytoplankton carbon biomass in the SYS during the spring, summer, and fall of 2018, and clarified its characteristics, distribution patterns and controlling factors. Phytoplankton carbon biomass ranged from 2.33 to 84.74 μg C/L in spring, 1.19–1454.25 μg C/L in summer, and 0.01–33.20 μg C/L in fall in the SYS. Diatoms were the most dominant group, contributing 53%, 68%, and 67% to the total phytoplankton carbon in spring, summer, and fall, respectively, followed by dinoflagellates, which contributed 46%, 31%, and 30%. The carbon biomass of diatoms and dinoflagellates exhibited quite distinct correlations with environmental factors. Diatoms exhibited stronger nutrient dependency, whereas no significant correlation was observed between dinoflagellates and nutrients, reflecting the different nutritional strategies of the two groups (strict autotrophy vs. mixotrophy). Compared to cell abundance, carbon biomass revealed a significantly higher proportion of dinoflagellate biomass in the community structure, which is primarily due to the significant interspecies variations in cell volume. Dinoflagellates tend to have larger cell volumes compared to diatoms in the SYS, leading to an underestimation of dinoflagellate proportions when using cell abundance alone. This indicates that simply using cell abundance may lead to cognitive bias in recognizing phytoplankton community structure, and taking carbon biomass into account will provide a more comprehensive understanding.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105404"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145287","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 : 2025-02-01DOI: 10.1016/j.csr.2024.105393
Muhammet Duman , Atilla Hüsnü Eronat , Ezgi Talas , Murat Cenk Gerdanlı , Caner Tükel
This study investigates the sources, levels, and distribution of heavy metals in the surficial sediments of the Çandarlı Gulf, examining both natural and anthropogenic influences. Using sediment transport models, pollution assessments, and principal component analysis (PCA), have been identified mean metal concentrations in sediments as Zn > Cr > Pb > Ni > Cu > As. PCA revealed five key sources: natural processes, biogenic impacts, anthropogenic activities, industrial runoff, and wastewater. The sediment characteristics vary regionally, with high-energy conditions and sand dominance in the south, and finer materials in the north. High carbonate content in sandy areas links to mechanical abrasion. Trace elements like As, Cr, Cu, Pb and Zn exceed background values in southern and northeastern zones due to activities like container handling and ship dismantling. Ecological risk assessments show frequent adverse effects for Ni and As, and occasional effects for Cu and Zn. The study emphasizes the need for comprehensive pollution control strategies to protect the Çandarlı Gulf's marine ecosystem.
{"title":"Understanding heavy Metal pollution dynamics in Çandarlı Gulf, western Türkiye: Insights from spatial analysis, sediment transport modeling and ecological risk assessment","authors":"Muhammet Duman , Atilla Hüsnü Eronat , Ezgi Talas , Murat Cenk Gerdanlı , Caner Tükel","doi":"10.1016/j.csr.2024.105393","DOIUrl":"10.1016/j.csr.2024.105393","url":null,"abstract":"<div><div>This study investigates the sources, levels, and distribution of heavy metals in the surficial sediments of the Çandarlı Gulf, examining both natural and anthropogenic influences. Using sediment transport models, pollution assessments, and principal component analysis (PCA), have been identified mean metal concentrations in sediments as Zn > Cr > Pb > Ni > Cu > As. PCA revealed five key sources: natural processes, biogenic impacts, anthropogenic activities, industrial runoff, and wastewater. The sediment characteristics vary regionally, with high-energy conditions and sand dominance in the south, and finer materials in the north. High carbonate content in sandy areas links to mechanical abrasion. Trace elements like As, Cr, Cu, Pb and Zn exceed background values in southern and northeastern zones due to activities like container handling and ship dismantling. Ecological risk assessments show frequent adverse effects for Ni and As, and occasional effects for Cu and Zn. The study emphasizes the need for comprehensive pollution control strategies to protect the Çandarlı Gulf's marine ecosystem.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105393"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145168","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 : 2025-02-01DOI: 10.1016/j.csr.2024.105396
Kristhal Doto , Pablo Silva , Rémi Bouyssou , Isabel Jálon-Rojas , Elisa Helena Fernandes
The contamination by plastic waste in aquatic environments has become a global issue, scientifically reported since 1970. The size and durability of microplastics (MPs, 1 μm > 5 mm) have made these debris widely distributed in aquatic environments. Despite various ongoing initiatives, there is a need to fill gaps in understanding how MPs are transported from their release sources to their final destinations. Therefore, understanding the distribution and dynamics of MPs in coastal areas, such as lagoons and estuaries, which are considered continental sources of MPs to the oceans, is essential to help fill these gaps and propose alternatives for managing what is the environmental problem of the century. In this context, this study aimed to assess the transport patterns of MPs in Patos Lagoon, the largest choked coastal lagoon in the world, considering contrasting meteoceanographic conditions in the system dynamics, such as wind and discharge. Using the hydrodynamic model TELEMAC-3D and the model for plastics particles TrackMPD, simulations were performed using a type of MP polymer (Polypropylene - PP). The simulations of MP transport considered advection, dispersion and the contribution of biofilm in increasing particle density (representing high-density microplastics). The results indicated a gradient of MPs retention from north to south, with higher concentrations of MPs occurring in the northern part of the system. The central region of the lagoon showed a greater tendency for MP export towards the southern region than retention. Meanwhile, the estuary region of Patos Lagoon exhibited a tendency for export of low-density MPs free of biofilm and retention of higher-density MPs, subject to the action of the Plastisphere. Additionally, based on the results obtained from density occurrence maps, it was possible to suggest potential accumulation areas of MPs throughout the lagoon system, reinforcing that the system can act as a sink in specific regions.
{"title":"Dynamics of low and high density microplastics in the world's largest choked coastal lagoon under contrasting meteoceanographic conditions","authors":"Kristhal Doto , Pablo Silva , Rémi Bouyssou , Isabel Jálon-Rojas , Elisa Helena Fernandes","doi":"10.1016/j.csr.2024.105396","DOIUrl":"10.1016/j.csr.2024.105396","url":null,"abstract":"<div><div>The contamination by plastic waste in aquatic environments has become a global issue, scientifically reported since 1970. The size and durability of microplastics (MPs, 1 μm > 5 mm) have made these debris widely distributed in aquatic environments. Despite various ongoing initiatives, there is a need to fill gaps in understanding how MPs are transported from their release sources to their final destinations. Therefore, understanding the distribution and dynamics of MPs in coastal areas, such as lagoons and estuaries, which are considered continental sources of MPs to the oceans, is essential to help fill these gaps and propose alternatives for managing what is the environmental problem of the century. In this context, this study aimed to assess the transport patterns of MPs in Patos Lagoon, the largest choked coastal lagoon in the world, considering contrasting meteoceanographic conditions in the system dynamics, such as wind and discharge. Using the hydrodynamic model TELEMAC-3D and the model for plastics particles TrackMPD, simulations were performed using a type of MP polymer (Polypropylene - PP). The simulations of MP transport considered advection, dispersion and the contribution of biofilm in increasing particle density (representing high-density microplastics). The results indicated a gradient of MPs retention from north to south, with higher concentrations of MPs occurring in the northern part of the system. The central region of the lagoon showed a greater tendency for MP export towards the southern region than retention. Meanwhile, the estuary region of Patos Lagoon exhibited a tendency for export of low-density MPs free of biofilm and retention of higher-density MPs, subject to the action of the Plastisphere. Additionally, based on the results obtained from density occurrence maps, it was possible to suggest potential accumulation areas of MPs throughout the lagoon system, reinforcing that the system can act as a sink in specific regions.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105396"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145170","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 : 2025-02-01DOI: 10.1016/j.csr.2024.105386
Konstantin I. Gurov , Ekaterina А. Kotelyanets , Anna A. Zhuravleva , Dmitrii A. Kremenchutskii
The Kerch Strait is a shipping artery connecting the Black Sea and the Sea of Azov and plays an essential role in the transportation of chemicals between the seas, fishing, socio-economic and tourism activities. The primary factors affecting the strait's ecosystem are construction in the coastal zone (e.g., Crimean Bridge), dredging and soil dumping, port enterprises' operations and shipping. It is known that high concentrations of radionuclides and heavy metals (HMs) are harmful to aquatic organisms and human health due to their persistence, bioaccumulation, acute and chronic toxicity. The study aims to reveal the peculiarities of the spatial distribution of radionuclides (137Cs, 40K, 210Pbex, 226Ra, 232Th) and HMs concentration (Cu, Fe, Cr, Pb, Ni, V, Zn, As, Mn, Ti) in the sediments of the Kerch Strait, assess their sedimentation fluxes, radiological hazard parameters and pollution indices. For this purpose, 12 samples of the surface sediments and four cores were collected in the strait in 2020. The concentration of most radionuclides and HMs in the surface sediments directly correlated with the percentage of mud fraction (r = 0.28–0.90) and TOC (r = 0.41–0.95). The results of Hierarchical cluster analysis and Principal component analysis indicated the presence of two sources of HMs in the surface sediments: geogenic and combined (geogenic + anthropogenic). From the mid-90s to 2020 the sediment and mass accumulation rates increased by a factor of 1.9 and 1.4, respectively. The temporal variability of radionuclides and HMs fluxes into sediments was reconstructed. The sedimentation flux of 137Cs during 1980–1987 was nine times higher than that in 2014–2020. The average sedimentation fluxes of Fe, Zn and Pb during 2014–2020 additionally increased by 31, 21 and 25%, respectively. The radiological hazard parameters indicated no significant health risk to humans from radionuclides and no enrichment/pollution for most HMs. The main exceptions were Cr, Pb and As, for which the geoaccumulation index reached unpolluted to moderately polluted levels while the enrichment factor reached strong, minor and moderate levels, respectively.
{"title":"Radionuclides and heavy metals in the Kerch Strait sediments: Spatial distribution, fluxes and pollution loads","authors":"Konstantin I. Gurov , Ekaterina А. Kotelyanets , Anna A. Zhuravleva , Dmitrii A. Kremenchutskii","doi":"10.1016/j.csr.2024.105386","DOIUrl":"10.1016/j.csr.2024.105386","url":null,"abstract":"<div><div>The Kerch Strait is a shipping artery connecting the Black Sea and the Sea of Azov and plays an essential role in the transportation of chemicals between the seas, fishing, socio-economic and tourism activities. The primary factors affecting the strait's ecosystem are construction in the coastal zone (e.g., Crimean Bridge), dredging and soil dumping, port enterprises' operations and shipping. It is known that high concentrations of radionuclides and heavy metals (HMs) are harmful to aquatic organisms and human health due to their persistence, bioaccumulation, acute and chronic toxicity. The study aims to reveal the peculiarities of the spatial distribution of radionuclides (<sup>137</sup>Cs, <sup>40</sup>K, <sup>210</sup>Pb<sub>ex</sub>, <sup>226</sup>Ra, <sup>232</sup>Th) and HMs concentration (Cu, Fe, Cr, Pb, Ni, V, Zn, As, Mn, Ti) in the sediments of the Kerch Strait, assess their sedimentation fluxes, radiological hazard parameters and pollution indices. For this purpose, 12 samples of the surface sediments and four cores were collected in the strait in 2020. The concentration of most radionuclides and HMs in the surface sediments directly correlated with the percentage of mud fraction (r = 0.28–0.90) and TOC (r = 0.41–0.95). The results of Hierarchical cluster analysis and Principal component analysis indicated the presence of two sources of HMs in the surface sediments: geogenic and combined (geogenic + anthropogenic). From the mid-90s to 2020 the sediment and mass accumulation rates increased by a factor of 1.9 and 1.4, respectively. The temporal variability of radionuclides and HMs fluxes into sediments was reconstructed. The sedimentation flux of <sup>137</sup>Cs during 1980–1987 was nine times higher than that in 2014–2020. The average sedimentation fluxes of Fe, Zn and Pb during 2014–2020 additionally increased by 31, 21 and 25%, respectively. The radiological hazard parameters indicated no significant health risk to humans from radionuclides and no enrichment/pollution for most HMs. The main exceptions were Cr, Pb and As, for which the geoaccumulation index reached unpolluted to moderately polluted levels while the enrichment factor reached strong, minor and moderate levels, respectively.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105386"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145175","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 : 2025-02-01DOI: 10.1016/j.csr.2024.105390
Safa Y. Abdo , Inga Zinicovscaia , Nikita Yushin , Omari Chaligava
This study presents a long-term follow-up investigation into the pollution levels of two significant harbors, Al-Luhaya and Al-Saleef, in the southern Red Sea (Hodeidah/Yemen) using inductively coupled plasma optical emission spectroscopy (ICP-OES). In Al-Luhaya harbor, the mass fractions of elements followed the sequence: S > Al > Fe > Ba >Mn > Zn > V > Cu > Ni > Cr > Cd > Pb > Co, while in Al-Saleef, the sequence was S > Al > Fe > Ba >Mn > Zn > V > Ni > Cu > Cr > Pb > Co > Cd. Sulfur was the dominant element in corals, its mass fraction changing in the range of 1188–1567 mg kg−1 in Al-Luhaya and 2066–3047 mg kg−1 in Al-Saleef. According to the Wilcoxon test, only the content of Zn in Al-Saleef corals was significantly higher than in Al-Luhaya ones. Correlation and principal component analyses were employed to disclose the elements’ relationship and associate them with pollution sources. The primary sources of the elements accumulated in corals are port activity, sewage discharge, and terrigenous input. The pollution load index and contamination factor were utilized to evaluate the extent of environmental pollution. The contamination factor values between 1 and 3.5 point at slight pollution with Fe in Al-Luhaya, while in Al-Saleef it was noted suspected contamination with Zn and Ni, and moderate pollution with Fe. The mass fractions of the elements in the present study were comparable or lower than values reported for corals collected in different zones of the Red Sea.
{"title":"Using scleractinian corals as monitors of essential and potentially toxic elements pollution in the southern Red Sea, Yemen Republic","authors":"Safa Y. Abdo , Inga Zinicovscaia , Nikita Yushin , Omari Chaligava","doi":"10.1016/j.csr.2024.105390","DOIUrl":"10.1016/j.csr.2024.105390","url":null,"abstract":"<div><div>This study presents a long-term follow-up investigation into the pollution levels of two significant harbors, Al-Luhaya and Al-Saleef, in the southern Red Sea (Hodeidah/Yemen) using inductively coupled plasma optical emission spectroscopy (ICP-OES). In Al-Luhaya harbor, the mass fractions of elements followed the sequence: S > Al > Fe > Ba >Mn > Zn > V > Cu > Ni > Cr > Cd > Pb > Co, while in Al-Saleef, the sequence was S > Al > Fe > Ba >Mn > Zn > V > Ni > Cu > Cr > Pb > Co > Cd. Sulfur was the dominant element in corals, its mass fraction changing in the range of 1188–1567 mg kg<sup>−1</sup> in Al-Luhaya and 2066–3047 mg kg<sup>−1</sup> in Al-Saleef. According to the Wilcoxon test, only the content of Zn in Al-Saleef corals was significantly higher than in Al-Luhaya ones. Correlation and principal component analyses were employed to disclose the elements’ relationship and associate them with pollution sources. The primary sources of the elements accumulated in corals are port activity, sewage discharge, and terrigenous input. The pollution load index and contamination factor were utilized to evaluate the extent of environmental pollution. The contamination factor values between 1 and 3.5 point at slight pollution with Fe in Al-Luhaya, while in Al-Saleef it was noted suspected contamination with Zn and Ni, and moderate pollution with Fe. The mass fractions of the elements in the present study were comparable or lower than values reported for corals collected in different zones of the Red Sea.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105390"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145099","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 : 2025-02-01DOI: 10.1016/j.csr.2024.105400
Monray D. Belelie , Roelof P. Burger , Johanna R.C. von Holdt , Rebecca M. Garland , Gadaffi M. Liswaniso , Sandy J. Thomalla , Stuart J. Piketh
The Benguela upwelling system (BUS) is frequently subject to dust deposition from southern Africa, which supplies macronutrients and trace metals to the ocean. The impact of these nutrients on chlorophyll-a (Chl-a) in the BUS was investigated using the first-ever mesocosm study from 29 September to October 12, 2022. The study employed a single triplicate treatment where mesocosms were seeded with dust (DG) from the Kuiseb ephemeral riverbed, one of the leading dust sources in southern Africa and one unamended control (CM). All mesocosms were also seeded with equal amounts of Chaetoceros, Pavlova, and Tetraselmis, species of phytoplankton commonly found in the BUS. Temporal dynamics in Chl-a, iron (Fe), nitrate (NO3−), silicon (Si), orthophosphate (PO43−), and light intensity were measured. The data suggests that adding dust from the Namib desert elicited a positive response from the phytoplankton in the BUS, as evidenced by higher Chl-a concentrations in the DG compared to the CM. This study demonstrates the likely importance of southern African dust emission and deposition for phytoplankton productivity in the adjacent BUS.
{"title":"Namib desert dust affects phytoplankton biomass in the Benguela upwelling region: Insights from first mesocosm study","authors":"Monray D. Belelie , Roelof P. Burger , Johanna R.C. von Holdt , Rebecca M. Garland , Gadaffi M. Liswaniso , Sandy J. Thomalla , Stuart J. Piketh","doi":"10.1016/j.csr.2024.105400","DOIUrl":"10.1016/j.csr.2024.105400","url":null,"abstract":"<div><div>The Benguela upwelling system (BUS) is frequently subject to dust deposition from southern Africa, which supplies macronutrients and trace metals to the ocean. The impact of these nutrients on chlorophyll-a (Chl-a) in the BUS was investigated using the first-ever mesocosm study from 29 September to October 12, 2022. The study employed a single triplicate treatment where mesocosms were seeded with dust (DG) from the Kuiseb ephemeral riverbed, one of the leading dust sources in southern Africa and one unamended control (CM). All mesocosms were also seeded with equal amounts of <em>Chaetoceros</em>, <em>Pavlova</em>, and <em>Tetraselmis</em>, species of phytoplankton commonly found in the BUS. Temporal dynamics in Chl-a, iron (Fe), nitrate (NO<sub>3</sub><sup>−</sup>), silicon (Si), orthophosphate (PO<sub>4</sub><sup>3−</sup>), and light intensity were measured. The data suggests that adding dust from the Namib desert elicited a positive response from the phytoplankton in the BUS, as evidenced by higher Chl-a concentrations in the DG compared to the CM. This study demonstrates the likely importance of southern African dust emission and deposition for phytoplankton productivity in the adjacent BUS.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105400"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145172","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}
Pub Date : 2025-02-01DOI: 10.1016/j.csr.2024.105395
Zhaoyun Chen , Jin Feng , Tengfei Li , Shuwen Zhang , Qiang Lian , Fei Wang
Ocean fronts are characterized by active vertical shear and mixing, which play a role in primary production, fishery resources, and marine ecosystems. While oceanographers have focused on the dynamics and biogeochemical processes of the Pearl River Plume, the seasonal variations of the plume front remain unclear. In this study, we investigate the seasonal and interannual variations in front intensity within and around the Pearl River Estuary by extracting remote sensing turbidity gradient images using the BOA algorithm. We then apply a deep learning technique to these turbidity gradient images to detect river plume fronts. The deep learning network successfully identifies two types of Pearl River Plume fronts: one with clear and distinct features, and the other displaying diffuse and fragmented characteristics. We further map the seasonal dispersal patterns of the Pearl River Plume front probability, revealing westward and eastward distributions of plume fronts in summer, and a more frequent westward distribution in autumn and winter. A front hotspot is observed near the western coast off the Pearl River Estuary, where the strength of front probability is influenced by the magnitude of the northeasterly wind.
{"title":"Seasonal variability of the Pearl River Plume front based on deep learning","authors":"Zhaoyun Chen , Jin Feng , Tengfei Li , Shuwen Zhang , Qiang Lian , Fei Wang","doi":"10.1016/j.csr.2024.105395","DOIUrl":"10.1016/j.csr.2024.105395","url":null,"abstract":"<div><div>Ocean fronts are characterized by active vertical shear and mixing, which play a role in primary production, fishery resources, and marine ecosystems. While oceanographers have focused on the dynamics and biogeochemical processes of the Pearl River Plume, the seasonal variations of the plume front remain unclear. In this study, we investigate the seasonal and interannual variations in front intensity within and around the Pearl River Estuary by extracting remote sensing turbidity gradient images using the BOA algorithm. We then apply a deep learning technique to these turbidity gradient images to detect river plume fronts. The deep learning network successfully identifies two types of Pearl River Plume fronts: one with clear and distinct features, and the other displaying diffuse and fragmented characteristics. We further map the seasonal dispersal patterns of the Pearl River Plume front probability, revealing westward and eastward distributions of plume fronts in summer, and a more frequent westward distribution in autumn and winter. A front hotspot is observed near the western coast off the Pearl River Estuary, where the strength of front probability is influenced by the magnitude of the northeasterly wind.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105395"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145173","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 : 2025-02-01DOI: 10.1016/j.csr.2025.105401
Zili Liu , Yonghao Jia , Yin Fang , Yujue Wang , Jianhua Gao , Yunying Duan , Meng Li , Qi Wang , Dongyan Liu
Coastal fronts are important physical boundary between coastal and offshore water masses in the ocean. The secondary circulation generated by fronts can greatly impact matter transport across fronts, leading to the different sedimentary environments between water masses. To understand the combined effects of fronts and water masses on the sedimentary environment in the East China Sea, we studied the spatial patterns of grain size, organic matter and biomarkers in surface sediments crossing the Min-Zhe Coastal Front (MZCF), combined with observational data in the upper ocean. The results showed that the front and water masses jointly determined the spatial pattern of sedimentary environments in the East China Sea. Marine organic matter dominated in the mud area, with higher concentrations at the frontal region. Terrestrial organic matter exhibited a decreasing trend from nearshore to offshore, particularly at the frontal shore-side, indicating the barrier effect of the front on coastal matter transport. The mean ratio between brassicasterol and dinosterol (B/D) in the sediments of MZCF and East China Sea coastal water mass (ECSCoW) was 2.8, which was lower than the B/D (3.8) in the sediments of East China Sea shelf water mass (ECSSW) and indicated that dinoflagellates are confined at the frontal shore-side water mass. The spatial patterns of diatom and dinoflagellate pigments in the water column were consistent with the biomarker patterns in the sediments and corresponded to the different habitats (e.g., nutrients, salinity) generated by the ECSCoW, ECSSW, and MZCF. The study explained the combined effects of front and water masses on sedimentary environments in the East China Sea and suggested to use fronts as boundary to distinguish water mass environments in paleo-oceanographic reconstruction.
{"title":"Effect of coastal front and water masses on the spatial pattern of sedimentary biomarkers in the East China Sea","authors":"Zili Liu , Yonghao Jia , Yin Fang , Yujue Wang , Jianhua Gao , Yunying Duan , Meng Li , Qi Wang , Dongyan Liu","doi":"10.1016/j.csr.2025.105401","DOIUrl":"10.1016/j.csr.2025.105401","url":null,"abstract":"<div><div>Coastal fronts are important physical boundary between coastal and offshore water masses in the ocean. The secondary circulation generated by fronts can greatly impact matter transport across fronts, leading to the different sedimentary environments between water masses. To understand the combined effects of fronts and water masses on the sedimentary environment in the East China Sea, we studied the spatial patterns of grain size, organic matter and biomarkers in surface sediments crossing the Min-Zhe Coastal Front (MZCF), combined with observational data in the upper ocean. The results showed that the front and water masses jointly determined the spatial pattern of sedimentary environments in the East China Sea. Marine organic matter dominated in the mud area, with higher concentrations at the frontal region. Terrestrial organic matter exhibited a decreasing trend from nearshore to offshore, particularly at the frontal shore-side, indicating the barrier effect of the front on coastal matter transport. The mean ratio between brassicasterol and dinosterol (B/D) in the sediments of MZCF and East China Sea coastal water mass (ECSCoW) was 2.8, which was lower than the B/D (3.8) in the sediments of East China Sea shelf water mass (ECSSW) and indicated that dinoflagellates are confined at the frontal shore-side water mass. The spatial patterns of diatom and dinoflagellate pigments in the water column were consistent with the biomarker patterns in the sediments and corresponded to the different habitats (e.g., nutrients, salinity) generated by the ECSCoW, ECSSW, and MZCF. The study explained the combined effects of front and water masses on sedimentary environments in the East China Sea and suggested to use fronts as boundary to distinguish water mass environments in paleo-oceanographic reconstruction.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105401"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145284","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}
Pub Date : 2025-02-01DOI: 10.1016/j.csr.2024.105373
Jochen Kämpf
The Bonney Coast Upwelling is a prominent seasonal coastal upwelling region that develops during November–April on Australia's southeastern continental shelf. This study couples a three-dimensional hydrodynamic model with a nitrogen-phytoplankton-zooplankton-detritus (NPZD) model to explore the plankton dynamics during the upwelling season. Findings suggest that, while the physical response to upwelling-favorable winds occurs rapidly on a timescale of 5–10 days, phytoplankton blooms develop only slowly on time scales of ∼30–60 days. To this end, the region of high zooplankton levels is predicted to form slowly on timescales of 2–3 months. As expected, the zooplankton maximum develops downstream from the upwelling center in the shallow waters of an adjacent bay (i.e., Long Bay) over an alongshore distance of 200–300 km. Unexpectedly, high zooplankton levels also develop on the inner shelf adjacent to the upwelling plume on spatial scales of 20–30 km, mainly due to the onshore transport of phytoplankton via lateral turbulent diffusion. Overall, remineralization by detritus contributes significantly (>50%) as nitrogen source to the photosynthetic phytoplankton production on the continental shelf.
{"title":"Phytoplankton and zooplankton production in the Bonney Coast upwelling, Australia: A coupled physical-biological model investigation","authors":"Jochen Kämpf","doi":"10.1016/j.csr.2024.105373","DOIUrl":"10.1016/j.csr.2024.105373","url":null,"abstract":"<div><div>The Bonney Coast Upwelling is a prominent seasonal coastal upwelling region that develops during November–April on Australia's southeastern continental shelf. This study couples a three-dimensional hydrodynamic model with a nitrogen-phytoplankton-zooplankton-detritus (NPZD) model to explore the plankton dynamics during the upwelling season. Findings suggest that, while the physical response to upwelling-favorable winds occurs rapidly on a timescale of 5–10 days, phytoplankton blooms develop only slowly on time scales of ∼30–60 days. To this end, the region of high zooplankton levels is predicted to form slowly on timescales of 2–3 months. As expected, the zooplankton maximum develops downstream from the upwelling center in the shallow waters of an adjacent bay (i.e., Long Bay) over an alongshore distance of 200–300 km. Unexpectedly, high zooplankton levels also develop on the inner shelf adjacent to the upwelling plume on spatial scales of 20–30 km, mainly due to the onshore transport of phytoplankton via lateral turbulent diffusion. Overall, remineralization by detritus contributes significantly (>50%) as nitrogen source to the photosynthetic phytoplankton production on the continental shelf.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105373"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145096","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}
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