{"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}
Shujin Guo , Feng Wang , Qingzhen Yao , Yanqing Wang , Meiping Feng , Xiaoxia Sun
{"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}
Safa Y. Abdo , Inga Zinicovscaia , Nikita Yushin , Omari Chaligava
{"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}
Monray D. Belelie , Roelof P. Burger , Johanna R.C. von Holdt , Rebecca M. Garland , Gadaffi M. Liswaniso , Sandy J. Thomalla , Stuart J. Piketh
{"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}
Zhaoyun Chen , Jin Feng , Tengfei Li , Shuwen Zhang , Qiang Lian , Fei Wang
{"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}
Zili Liu , Yonghao Jia , Yin Fang , Yujue Wang , Jianhua Gao , Yunying Duan , Meng Li , Qi Wang , Dongyan Liu
{"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}
{"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}
Birane Ndom , Siny Ndoye , Bamol Ali Sow , Vincent Echevin
{"title":"Tides in the Casamance estuary: A modeling study","authors":"Birane Ndom , Siny Ndoye , Bamol Ali Sow , Vincent Echevin","doi":"10.1016/j.csr.2024.105389","DOIUrl":"10.1016/j.csr.2024.105389","url":null,"abstract":"<div><div>The Casamance estuary, located in southern Senegal, is a region of remarkable ecological, tourist and economic significance. It undergoes strong seasonal variations of salinity due to its reverse estuary nature during the dry season. This study aims to characterize tidal dynamics in the western part of the Casamance estuary, spanning from the river mouth to the town of Ziguinchor, during the dry season. Utilizing a three-dimensional, non-linear model with a high spatial resolution, we focused on simulating the tidal elevations and currents and evaluating them with sea level and current measurements both within the estuary and at its mouth. Whereas modelled tidal elevations agreed with observations, revealing eastward tidal propagation within the estuary, tidal currents near the river mouth and into the estuary were underestimated. The Eulerian residual circulation was mainly seaward whereas the Lagrangian residual circulation was significantly weaker due to compensation by the Stokes drift. This modeling study marks a crucial first step towards conducting comprehensive environmental impact assessments in the Casamance estuary, paving the way for a deeper understanding and preservation of this region.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105389"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145166","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}
Jiajia Yao , Rujun Yang , Yingying Zhang , Minghan Zhu , Mengqi Bi , Kunyu Ma , Yuan Liu , He Xie , Yao Wu
{"title":"Temporal and spatial distribution of Fe(II) and dissolved iron and their influencing factors in the Yangtze River estuary","authors":"Jiajia Yao , Rujun Yang , Yingying Zhang , Minghan Zhu , Mengqi Bi , Kunyu Ma , Yuan Liu , He Xie , Yao Wu","doi":"10.1016/j.csr.2024.105385","DOIUrl":"10.1016/j.csr.2024.105385","url":null,"abstract":"<div><div>Iron (Fe) is an essential trace element for the growth and metabolism of marine plankton. Fe(II), the reduced form of iron, is highly soluble and more labile in seawater, contributing significantly to iron bioavailability in marine environments. This study investigates the temporal and spatial distributions of Fe(II) and dissolved iron (DFe) during autumn (October 11–22, 2018), spring (March 4–14, 2019), and summer (July 9–17, 2019) in the Yangtze River estuary. Fe(II) concentrations decreased from nearshore to offshore, with higher levels predominantly in areas influenced by Yangtze River water, indicating that terrestrial input from the river is the main source of Fe(II). Seasonal variations in Fe(II) concentrations were observed, with the highest levels in summer and the lowest in autumn. Median Fe(II) concentrations in autumn, spring and summer were 0.60 nM, 0.81 nM, and 1.33 nM, respectively. DFe concentrations generally decreased from nearshore to offshore, except in summer. The concentration of DFe exhibits seasonal variations. Median DFe concentrations in autumn, spring and summer were 16.10 nM, 44.65 nM, and 22.41 nM, respectively. Both Fe(II) concentrations and Fe(II)/DFe ratios peaked in summer surface waters. Significant correlations were found between Fe(II)/DFe ratios and NH<sub>4</sub>-N/DIN or NO<sub>3</sub>-N/DIN ratios in summer.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105385"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145167","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}
Filipe Vieira , Alexsandra S. Lima , Geórgenes H. Cavalcante
{"title":"Characterization of wave climate and trends for Alagoas State, NE Brazil","authors":"Filipe Vieira , Alexsandra S. Lima , Geórgenes H. Cavalcante","doi":"10.1016/j.csr.2024.105397","DOIUrl":"10.1016/j.csr.2024.105397","url":null,"abstract":"<div><div>This study presents a spectral wave model developed and validated for the Alagoas State in NE Brazil using satellite altimeter data. The model, spanning 32 years from 1979 to 2010, driven by CFSR wind forcing, captures the wave climate dynamics across seasons and regions. Energetic waves dominate winter and spring, contrasting with milder conditions in summer. Spatially, heightened wave activity is concentrated in the southern border with Sergipe, notably near the São Francisco River mouth, gradually tapering off towards the northern coast. Trends in significant wave height (H<sub>m0</sub>) reveal seasonal fluctuations, with winter and spring exhibiting positive trends, while summer trends are predominantly negative. Notably, winter trends peak at 0.6% per year along the central to southern coastal stretch. Conversely, summer witnesses a maximum negative trend of 0.4% per year nearshore. Over the 32-year span, the annual mean shows a general negative trend (∼0.2% per year) across most of the study area, albeit with minor positive trends in the northern region. Particularly noteworthy is the accelerated increase (∼0.4% per year) in extreme conditions (P99) nearshore where H<sub>m0</sub> reached 2.7 m on Maceió coast potentially exacerbating erosion and should be the object of further considerations for coastal management design.</div></div>","PeriodicalId":50618,"journal":{"name":"Continental Shelf Research","volume":"285 ","pages":"Article 105397"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145174","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}