Journal of Marine Systems最新文献

{"title":"Global surface ocean calcite saturation (Ωcal) estimation using satellite and in-situ observations","authors":"Ibrahim Shaik ,&nbsp;P.V. Nagamani ,&nbsp;Sandesh Yadav ,&nbsp;Yash Manmode","doi":"10.1016/j.jmarsys.2025.104054","DOIUrl":"10.1016/j.jmarsys.2025.104054","url":null,"abstract":"<div><div>Calcite saturation (Ω_<em>cal</em>) in global surface ocean waters is a crucial parameter for assessing marine ecosystem health. This study presents a multiparametric linear regression (MLR) model integrating satellite and in-situ observations to estimate global surface ocean Ω_<em>cal</em>. The model was developed using in-situ measurements of sea surface temperature (SST), sea surface salinity (SSS), total alkalinity (TA), dissolved inorganic carbon (DIC) and Ω_<em>cal</em> obtained from the National Center for Environmental Information (NCEI), combined with satellite derived chlorophyll concentrations (Chla). Model validation demonstrated strong agreement with in-situ data, indicating high accuracy of estimation. Satellite derived Ω_<em>cal</em> estimates also showed robust correlations with in-situ measurements, confirming the MLR model reliability. Sensitivity analysis highlighted the model resilience to variations in input parameters. This study reveals significant spatiotemporal variability in Ω_<em>cal</em>, driven by physical, chemical, and biological processes, including seasonal patterns and climate phenomena like the El Nino Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO). Analysis of interannual trends and the rate of change in Ω_<em>cal</em> emphasize the impacts of ocean acidification, revealing a declining trend that poses challenges to marine ecosystems. The proposed approach offers a valuable tool for monitoring global ocean carbonate chemistry, providing insights into the long term impacts of environmental changes on marine health and enabling informed decision making for ecosystem management.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"249 ","pages":"Article 104054"},"PeriodicalIF":2.7,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552997","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}

{"title":"Phytoplankton photosynthetic parameters and primary production in some Arctic regions during the summer of 2020","authors":"Tatiana Efimova ,&nbsp;Tatiana Churilova ,&nbsp;Elena Skorokhod ,&nbsp;Anatoly Buchelnikov ,&nbsp;Nataliia Moiseeva","doi":"10.1016/j.jmarsys.2025.104050","DOIUrl":"10.1016/j.jmarsys.2025.104050","url":null,"abstract":"<div><div>In August 2020, during the 80th cruise of the R/V “Akademik Mstislav Keldysh”, phytoplankton photosynthetic parameters were measured in the Norwegian Sea, the Barents Sea and the adjacent area of the Arctic Ocean. Primary production in the Arctic area was estimated using full spectral approach that took into account quantum yield of photosynthesis (ϕ), phytoplankton spectral light absorption coefficient and spectral downwelling irradiance. Total light absorption by all optically active components except water influenced spectral features of downwelling irradiance: increase of the total non-water light absorption at the sea surface layer resulted in a shift of the wavelength of the downwelling irradiance spectrum maximum to the longer wavelength (from 500 ± 7 nm to 530 ± 5 nm). Phytoplankton photosynthetic parameters (maximum quantum yield (ϕ_max) and light intensity saturating photosynthesis) were depth-dependent variables due to phytoplankton photoacclimation. Relationships between photosynthetically available radiation (PAR) vs. ϕ_max and PAR vs. ϕ were described. Although chlorophyll-<em>a</em> specific photosynthetic rate (P^B) ranged from 0.5 to 1.5 mgC/mgChl-<em>a</em>/h in the surface layer, daily primary production (1.1 mgC/m³/d - 32 mgC/m³/d) was correlated to chlorophyll-<em>a</em> concentration (Chl-<em>a</em>) (<em>r</em> = 0.97, <em>n</em> = 22, <em>p</em> &lt; 0.0001), which is likely to be caused by higher variability of Chl-<em>a</em> (0.07 mg/m³–1.5 mg/m³) compared to P^B. The full spectral approach developed for the Black Sea is relevant for correct assessment of primary production in the Arctic area.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"248 ","pages":"Article 104050"},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518930","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}

{"title":"Modeling how eutrophication in northern Baltic coastal zone is driven by new nutrient inputs, internal loading, and 3D hydrodynamics","authors":"Risto Lignell ,&nbsp;Elina Miettunen ,&nbsp;Harri Kuosa ,&nbsp;Janne Ropponen ,&nbsp;Laura Tuomi ,&nbsp;Irma Puttonen ,&nbsp;Kaarina Lukkari ,&nbsp;Marie Korppoo ,&nbsp;Markus Huttunen ,&nbsp;Karel Kaurila ,&nbsp;Jarno Vanhatalo ,&nbsp;Frede Thingstad","doi":"10.1016/j.jmarsys.2025.104049","DOIUrl":"10.1016/j.jmarsys.2025.104049","url":null,"abstract":"<div><div>The nutrient load and the resulting eutrophication responses in the Archipelago Sea, a northern Baltic Sea basin, were assessed by developing the FICOS model system (Finnish Coastal Nutrient Load Model). FICOS includes a simple but sufficiently mechanistic biogeochemical (BGC) model with two functional phytoplankton groups (strict autotrophs and diazotrophic N₂ fixing cyanobacteria) accounting for key processes in the Baltic nitrogen‑phosphorus cycle. The BGC model is linked to a high-resolution 3D hydrodynamic coastal model and includes all important nutrient sources. We applied Bayesian inference on time series of dissolved inorganic phosphorus (DIP), dissolved inorganic nitrogen (DIN), chlorophyll <em>a</em> (Chla), and algal biomass observations to estimate five unknown phytoplankton growth parameters of the BGC model, and the uncertainties associated with them, as well as to calibrate the model predictions. In general, the calibrated BGC model simulated well the time courses of the observations at three intensive monitoring stations in the Archipelago Sea.</div><div>Main sources of new nutrients to the Archipelago Sea include catchment area, atmosphere, point load (e.g. fish farming), N₂ fixation by cyanobacteria and background transport from open sea. An important and characteristic additional nutrient source in the shallow area is recycling from bottom sediments. During the season of phytoplankton growth, this internal load was the most important DIP source for the productive surface layer. In the sheltered basin coupled with the main river Aurajoki (area 1221 km²), about half of the DIP released from sediments was transported to the surface. For DIN in the Aurajoki basin, atmospheric deposition and catchment load were the most important sources for phytoplankton, both accounting for about 30 % of total surface inputs. In the whole Archipelago Sea, annual inputs of DIP and total P were dominated by internal load while atmospheric load was the most important DIN source. Import from the northern Baltic proper was the other main source of both forms of N and P.</div><div>During the growth season in the Aurajoki basin, high internal DIP load led to low surface DIN:DIP input ratio, indicating primary N-limitation of phytoplankton. The internal DIP load and catchment area DIN load were the local inputs with the widest impact areas in model simulations, suggesting that local inorganic nutrient loads were exhausted within the coastal zone during the growth season. Furthermore, Bayesian uncertainty analysis of nutrient load scenario predictions suggested that good environmental status (below 2.5–3.0 μg Chla L⁻¹) is achievable in the Aurajoki basin only with drastic reductions in practically all anthropogenic loads.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"249 ","pages":"Article 104049"},"PeriodicalIF":2.7,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644536","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":"Spatial and seasonal variability of Arctic phytoplankton communities in conditions of interaction with Atlantic origin waters in the St. Anna Trough (Kara Sea)","authors":"Valentina M. Sergeeva ,&nbsp;Svetlana V. Stepanova ,&nbsp;Mikhail V. Flint ,&nbsp;Irina N. Sukhanova ,&nbsp;Alexey V. Fedorov ,&nbsp;Vladimir A. Artemiev","doi":"10.1016/j.jmarsys.2025.104051","DOIUrl":"10.1016/j.jmarsys.2025.104051","url":null,"abstract":"<div><div>For the first time, seasonal changes in phytoplankton communities were described in the Kara Sea region, which is influenced by modified Atlantic water through the St. Anna Trough. The study focused on June, when the sea ice began to retreat, July after three weeks without sea ice, and September, when Siberian river discharge had a widespread surface impact. In all seasons, the structure of the phytoplankton community differed significantly on the outer shelf of the Kara Sea and the slope of the St. Anna Trough. This boundary was caused by changes in the hydrophysical structure and was located approximately at 76.5 N, with a width of about 20 km. The highest phytoplankton abundance, biomass and photosynthetic activity were observed on the outer Kara Sea shelf in the cold winter layer with temperature ranging from −1.7 to −0.5 °C and salinity ranging from 32.5 to 33.7. In June and July, the layer was located in conditions with sufficient underwater irradiance and nutrient supply. The integral abundance and biomass of algae differed 10–20 times between the outer shelf of the Kara Sea and the slope of the St. Anna Trough, where this layer was not present. In September, stratification on the Kara Sea shelf increased under the influence of pronounced river runoff, and the cold winter layer became thinner and deeper, with a significant decrease in phytoplankton abundance. Despite the high similarity (61–64 %) in species composition between the outer shelf and slope of St. Anna, there were differences in dominant species between the areas each month. In June the spring diatoms <em>Chaetoceros socialis</em>, Fragilariopsis spp. (<em>F. cylindrus</em>, <em>F. oceanica</em>) and <em>Navicula pelagica</em> mass developed on the Kara Sea outer shelf, while <em>Phaeocystis pouchetii</em> did on the slope of the St. Anna Trough. In July, resting spores of <em>Chaetoceros socialis</em>, as well as Apedinella radiance, and Choanoflagellates prevailed on the shelf, but <em>Dicrateria</em> sp. was the most abundant in the St. Anna Trough. In September <em>Leptocylindrus danicus</em>, <em>Peridiniella catenata</em> and <em>Thalassionema nitzschioides</em> were the base of community on the outer shelf, however <em>Thalassiosira</em> cf. <em>levanderii</em>, <em>Leptocylindrus minimus</em>, <em>Nephroselmis</em> sp. dominated on the slope. The “Atlantification” through the St. Anna Trough in June and July had a similar effect on the phytoplankton in the Kara Sea's outer shelf as it did on the phytoplankton communities in the Polar Front area of the Barents Sea during April–May.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"249 ","pages":"Article 104051"},"PeriodicalIF":2.7,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580592","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}

{"title":"Coastal zooplankton in the Palmer Archipelago, Western Antarctica Peninsula: Influence of environmental conditions at short-term scale during austral summer","authors":"Benjamín Rodríguez-Stepke ,&nbsp;Claudia Morales ,&nbsp;Manuel I. Castillo ,&nbsp;Ángela Rodríguez ,&nbsp;Manuel I. Castillo ,&nbsp;César A. Cárdenas ,&nbsp;Mario La Mesa ,&nbsp;Mathias Hüne ,&nbsp;Mauricio F. Landaeta","doi":"10.1016/j.jmarsys.2025.104047","DOIUrl":"10.1016/j.jmarsys.2025.104047","url":null,"abstract":"<div><div>Seasonal and inter-annual fluctuations in the zooplankton composition and abundance from West Antarctica are relatively well known. Nonetheless, there is scarce information about the zooplankton structure in Antarctic waters at shorter time and spatial scales. In this study, we analyzed short-term (i.e., days) temporal and spatial (i.e., km) variation in mesozooplankton from a shallow embayment (South Bay, Doumer Island, 64°52′S, 63°35′W) and surrounding zones off the Western Antarctic Peninsula (WAP), during the austral summer 2022. A total of 110 taxonomic groups were identified in the samples. Meroplankton (Asteroidea, Polychaeta, and Nemertea larvae) was more abundant inside the bay, while the opposite trend was observed for the holoplankton (Copepoda, Appendicularia, and Chaetognatha). Copepods numerically dominated the samples, particularly <em>Oithona</em> spp., <em>Calanoides acutus</em>, and <em>Paraeuchaeta</em> sp. Only meroplankton showed significant differences in the composition and abundance between zones, although alpha-diversity indices showed similar values inside and outside the bay. A Multivariate Regression Tree indicated that the pH (node 1) was the primary predictor separating zooplankton assemblages, followed by the east–west wind stress (Tau-U, node 2), and water stability (node 3). This study highlights the importance of shallow bays in the WAP for the aggregation of planktonic stages of benthic and demersal taxa.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"248 ","pages":"Article 104047"},"PeriodicalIF":2.7,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487838","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}

{"title":"Impact of coral bleaching on symbiotic microbial communities and carbon fixation pathways in the South China Sea","authors":"Fulin Sun ,&nbsp;Hongqiang Yang ,&nbsp;Xiyang Zhang ,&nbsp;Fei Tan ,&nbsp;Guan Wang ,&nbsp;Qi Shi","doi":"10.1016/j.jmarsys.2025.104046","DOIUrl":"10.1016/j.jmarsys.2025.104046","url":null,"abstract":"<div><div>Microorganisms play a crucial role in supplying essential nutrients to corals, thereby enhancing their survival under environmental stress. However, the diversity and ecological functions of carbon-fixing microorganisms in coral symbiosis remain poorly understood. In this study, we employed metagenomic analysis to investigate microbial responses to coral bleaching and their impact on carbon fixation pathways in the South China Sea. Principal coordinates Analysis (PCoA) revealed that both bleaching and coral species significantly influenced the symbiotic microbial community composition. Bleached corals exhibited a substantial increase in heterotrophic microorganisms. The findings demonstrated the presence of complete photosynthetic and prokaryotic carbon fixation pathways within coral holobionts, with a clear shift in microbial carbon metabolism following bleaching. Function analysis shows a decrease in key enzymes of photosynthetic carbon fixation and an increase in prokaryotic carbon fixation enzymes in bleached corals, indicating the activation of the prokaryotic carbon fixation pathway in bleached corals. In addition to Symbiodiniaceae, other microbial taxa contributed to carbon fixation, with Suessiales, Cladophorales, Oscillatoriales, Rhodospirillales, and Rhodobacterales identified as the major contributors. Notably, Cladophorales (<em>Boodlea</em> and <em>Botryococcus</em>) emerged as key contributors to RuBP carboxylase activity in bleached corals. These results highlight the significant role of microbial carbon fixation within coral holobionts and provide a foundation for future research on lineage-specific carbon-fixing microorganisms.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"248 ","pages":"Article 104046"},"PeriodicalIF":2.7,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445501","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}

{"title":"Phytoplankton dynamics in the Antarctic marginal ice zone: Trends and drivers","authors":"Prince Prakash,&nbsp;Rahul Mohan,&nbsp;Ravidas K. Naik,&nbsp;Alvarinho J. Luis","doi":"10.1016/j.jmarsys.2025.104044","DOIUrl":"10.1016/j.jmarsys.2025.104044","url":null,"abstract":"<div><div>The Southern Ocean's Marginal Ice Zone (MIZ) plays a crucial role in carbon cycling through its influence on phytoplankton biomass and distribution. Here we investigate the impact of climate change on phytoplankton dynamics in the MIZ using satellite-derived chlorophyll-a (Chl-<em>a</em>) data from 1997 to 2020. We observed significant (<em>P</em> &lt; 0.05) increases in Chl-<em>a</em> concentration across most sectors of the MIZ. We observed a significant expansion (&gt;30 %) in the spatial extent of high-biomass areas within the MIZ, with the highest increase in the Ross Sea. However, these trends are spatially variable, with offshore regions showing significant increases, while trends in shelf and coastal waters are mixed, including areas of decrease and non-significance. This indicates the potential for heightened productivity in the Antarctic Ocean region, leading to the export of additional carbon in the future. Furthermore, we establish connections between climate drivers and Chl-<em>a</em> trends, emphasizing the impact of freshening and stratification on Chl-<em>a</em> concentration. These changes in salinity and water column structure are critical factors influencing phytoplankton growth and distribution. Our findings contribute to a better understanding of the interlinked interactions between phytoplankton, sea ice dynamics, and climate variability in the MIZ. By explaining the links between environmental changes and biological responses, this study emphasizes the importance of these relationships for future climate change assessments.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"248 ","pages":"Article 104044"},"PeriodicalIF":2.7,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155279","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}

{"title":"Climatic and oceanographic variability associated with historical landings of blackspot seabream in the Strait of Gibraltar: Wavelet-based analysis","authors":"Víctor Sanz-Fernández ,&nbsp;Juan Carlos Gutiérrez-Estrada ,&nbsp;Dante Queirolo Palma ,&nbsp;Samuel Hormazábal Fritz","doi":"10.1016/j.jmarsys.2025.104045","DOIUrl":"10.1016/j.jmarsys.2025.104045","url":null,"abstract":"<div><div>Blackspot seabream [<em>Pagellus bogaraveo</em> (Brünnich, 1768)] is a demersal fish species of great commercial value for Spanish and Moroccan fleets operating in the zone of the Strait of Gibraltar. The influence of environmental and climatic effects on commercial landings of this species are not fully understood. The aim of this paper is to explore, analysis and identify potential relationships between climate and oceanographic forcing and fishery production. For this purpose, we use wavelet analysis, time domain and time-frequency domain. Monthly landings of this transboundary resource at the Spanish ports of Algeciras, Ceuta, Conil and Tarifa and the Moroccan port of Tangier between 1983 and 2015 have been characterised by two main cycles, from 1990 to 2000 and 2005 to 2015, and marked seasonality, with landings being larger between April and July and smaller in January, February and September. Time-frequency analysis found that fish landings series had high variance (high energy fluctuations) during two cycles with dominant 6- and 12- month periodicities. Further, bivariate time-frequency analysis exploring the relationship of fish landings with a wide range of climate indices and oceanographic variables suggest that the dynamics of the landings are associated with climatic and oceanographic variability. Given this, larger fish landings may be attributable to environmental conditions favouring both population reproduction and fishing success.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"248 ","pages":"Article 104045"},"PeriodicalIF":2.7,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143154632","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}

{"title":"Phytoplankton size structure in a subtropical area from ocean colour and its applications","authors":"Andréa de Lima Oliveira ,&nbsp;Natália Rudorff ,&nbsp;Shubha Sathyendranath ,&nbsp;Fabio Dall Cortivo ,&nbsp;Silvana Vianna Rodrigues ,&nbsp;Daniela Sudatti ,&nbsp;Milton Kampel","doi":"10.1016/j.jmarsys.2024.104036","DOIUrl":"10.1016/j.jmarsys.2024.104036","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Ocean colour remote sensing provides information on phytoplankton biomass at the global scale, indexed as chlorophyll-&lt;em&gt;a&lt;/em&gt; concentration (Chl-&lt;em&gt;a&lt;/em&gt;). Several models have also been developed to estimate phytoplankton size classes (PSCs) from ocean colour data. Here we evaluate an abundance-based (AB) model that relies on the total Chl-&lt;em&gt;a&lt;/em&gt; as input and the spectral-based (SB) model that relies on the spectrally-resolved phytoplankton absorption coefficient (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;). The models were regionally adjusted using &lt;em&gt;in situ&lt;/em&gt; data from a coastal time-series station in the South Brazil Bight, Southwestern Atlantic Ocean (ANTARES-Ubatuba). The regionally-adjusted models were applied to MODIS/Aqua images from 2002 to 2021, using the Generalized Inherent Optical Properties model (GIOP) to estimate Chl-&lt;em&gt;a&lt;/em&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;. The satellite time series was used to analyse the spatio-temporal variability of phytoplankton size classes. A correlation analysis was then performed with annual mean sea surface temperature (SST), Chl-&lt;em&gt;a&lt;/em&gt;, and micro and nanophytoplankton size fractions (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;F&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;). The Multivariate El Niño-Southern Oscillation Index (MEI) was used to investigate the influence of the El Niño-Southern Oscillation (ENSO) in the study region. Both PSC models performed reasonably well when tested against an independent &lt;em&gt;in-situ&lt;/em&gt; dataset collected in the study region, yielding a correlation coefficient &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;ρ&lt;/mi&gt;&lt;mo&gt;&gt;&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;0.6 and a &lt;span&gt;&lt;math&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-value &lt;span&gt;&lt;math&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;0.01. The AB model underestimated the Chl-&lt;em&gt;a&lt;/em&gt; associated with the micro- and nano-sized classes (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) by 20%, while the SB model underestimated it by 48%. The AB model underestimated &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;F&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; by 12% and the SB by 6%. The satellite validation for the &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;F&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; showed an underestimation of 5% by the AB model and an overestimation of 18% by the SB model. A seasonal pattern was observed, with &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;F&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; dominating the inner shelf during the austral summer and spring, and extending to the entire shelf during the autumn and winter. The micro- and nano-sized fractions showed a significant negative correlation with SST, whereas MEI was positively correlated with Chl-&lt;em&gt;a&lt;/em&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;F&lt;/mi&gt;","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"248 ","pages":"Article 104036"},"PeriodicalIF":2.7,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143154631","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}

{"title":"Impacts of the closure of the Mozambique Channel on the southwest Indian Ocean circulation: A regional numerical simulation","authors":"Théo Le Hir ,&nbsp;Pierrick Penven ,&nbsp;Thierry Huck ,&nbsp;Romain Pellen ,&nbsp;Maryline Moulin ,&nbsp;Marina Rabineau ,&nbsp;Daniel Aslanian","doi":"10.1016/j.jmarsys.2024.104024","DOIUrl":"10.1016/j.jmarsys.2024.104024","url":null,"abstract":"<div><div>Paleobathymetric reconstructions suggest that 35 million years ago, local uplift of the Davie Ridge could have temporarily raised a continental land–bridge between Africa and Madagascar and dramatically affected their connectivity. Numerical simulations of a regional model of the southwest Indian Ocean at mesoscale resolution are performed to investigate the consequences of such a closure of the Mozambique Channel. Compared to a reference simulation of present day circulation, blocking the Mozambique Channel results in a redistribution of the transport around Madagascar dramatically strengthening the East Madagascar Current and eddy variability south of Madagascar, broadening the Agulhas Current, and modifying water mass properties and bottom circulation.</div></div>","PeriodicalId":50150,"journal":{"name":"Journal of Marine Systems","volume":"247 ","pages":"Article 104024"},"PeriodicalIF":2.7,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143179979","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}