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Exchanges and interactions between water masses are typically concentrated across ocean fronts, requiring targeted sampling. As fronts are dynamic in their spatiotemporal extent, they can be hard to map with limited sampling resources. In this paper, we use horizontal temperature gradient as the defining feature of a front to adapt the path of an autonomous underwater vehicle to follow these regions of scientific interest. We present results from simulations and successful field operations in the Barents Sea, where the vehicle equipped with a microstructure sensor crossed the polar front while adapting its trajectory to the front position. Using in situ measurements, we estimate the temperature gradient across the polar front and cross it at different depths. We show that the vehicle is able to estimate and detect the temperature gradient maximum and to adjust its path to provide measurements of temperature, salinity and microstructure along its path, on both sides of the front. This is a step toward the integration of turbulence measurements on autonomous underwater vehicles, showing promise of more targeted sampling of turbulence in regions of large spatial gradients and interactions between water masses, such as fronts. The horizontal vehicle path complements the more traditional vertical profile measurements, providing a finer horizontal spatial resolution. The adaptive behavior of autonomous agents contributes to increased accuracy in targeted measurements as well as expanded resource utilization. [ABSTRACT FROM AUTHOR]

We present standardized, quantitative information on the avifauna of the Drake Passage obtained during six crossings between Patagonia and the South Shetland Islands during the summer-autumn period, 1998-2020. We compare inter-annual and seasonal patterns of species occurrence, adding to previous, published surveys, and we discuss species association with the different zones and water masses of the region. [ABSTRACT FROM AUTHOR]

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Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Santos Basin (SB) is the main petroliferous basin in the Brazilian continental margin and one of the most studied marine areas in Brazil. However, historical data suggest that new efforts should be carried out to acquire quantitative biological data, especially in the deep sea, to establish the baseline of essential ocean variables in different ecosystems for future monitoring programs. The Brazilian energy company Petrobras planned and executed 24 oceanographic cruises over a period of 2 years to assess the benthic (SANSED cruise) and pelagic (SANAGU cruise) systems of the SB (356 days at sea in 2019 and 2021/2022). These efforts were part of the Santos Project, which comprised a comprehensive environmental study aimed at investigating benthic and pelagic variables to characterize ecology, biogeochemistry, thermohaline properties of water masses, and ocean circulation patterns, geomorphology, and sedimentology, as well as organic and inorganic chemistry. Here we present the detailed sampling designs and the field methods employed on board, during the SB scientific cruises. All sampling protocols were based on standardized approaches. For the benthos analyses, triplicate sediment samples were performed using a GOMEX-type box corer (0.25 m²) or a large modified Van Veen grab (0.75 m²) at 100 stations ranging from 25 to 2400 m depth. At each station, 25 geochemical and physico-chemical parameters were analyzed in addition to micro-, meio-, and macrofauna and living foraminifera samples. For the pelagic system, 60 stations were selected to investigate the plankton community, ranging in size from pico- to macroplankton, through vertical, horizontal, and oblique net hauls (20, 200, and 500 µm mesh size), as well as 25 biogeochemical parameters collected with an aid of a CTD-rosette sampler. Part of this scientific information also serves the Regional Environmental Characterization Project (PCR-BS) in support of Petrobras' Santos Basin drilling licensing process led by the Brazilian Environmental Agency - IBAMA. This project contributes to the sustainable development of the SB, in line with the guidelines of the United Nations Decade of Ocean Science for Sustainable Development. [ABSTRACT FROM AUTHOR]

This study describes the hydrography and water masses of the Santos Basin Continental Shelf (SBCS) during two hydrographic campaigns (SANAGU, SANSED) in 2019. Coastal Water (CW) is the dominant water mass in the southern portion of the SBCS, with relatively low salinity values (S<35.5 g kg-1), and satellite data show that local precipitation and river discharge could not account for the low salinity observed during the cruises in the southern region of the domain. The low salinity observed is explained by the transport from the south influenced by Subtropical Shelf Water (STSW), which was influenced by the La Plata River discharge. In the northern region of the SBCS, the South Atlantic Central Water (SACW) dominates the bottom layers of the water column, with the wind playing a major role in the uplift of this water mass, as evidenced by a wind impulse analysis. In this part of the shelf, Tropical Water (TW) was the second water mass in volume and occupied the surface layers and offshore the shelf. CW is restricted to a thin surface layer, which reaches distances of a few kilometers from the coast. Our analysis show the differences in the hydrographic structure of the SBCS and suggests that the SBCS can be divided in two regions with distinct characteristics: 1) the area southwest of São Sebastião, where the hydrographic parameters were modulated by the presence of the Subtropical Shelf Water (STSW); 2) the area northeast of São Sebastião, where the uplifting of SACW was the dominant process. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A data-driven approach to assess the occurrence of thermal stratification and the depth of the thermocline in water masses has been developed and tested in the Spanish reservoir of El Val. The novelty of this approach is that it relies only on readily available data that can be collected for almost any reservoir, providing water managers with a transferable tool that can be easily adapted for any other reservoirs or lakes. The input variables were meteorological data, the water level and the output flow. A non-supervised clustering technique, k-means , was used to identify the stratification period with unlabelled data, that is to say inferring patterns when data from the target variable is not available. As a supervised method, Artificial Neural Networks were used to classify a given day as having or not having stratification and, in the positive case, to infer the depth of the thermocline. The classification showed a very high accuracy (96%) and the estimation of the thermocline depth showed a mean absolute error (MAE) of 1.94 m and 1.99 m in the training and test fractions, respectively. Shapley Additive Explanations (SHAP) values were used to improve the explainability and they revealed that the most important features to infer the depth of the thermocline were the water level, the daily average solar irradiance and the air temperature. [Display omitted] • Open data relating water quality continuous monitoring in a reservoir are used. • Clustering technique allows identifying stratification periods. • Meteorological, storage state and flow data allow inferring the thermal behaviour. • Up to 3 days-lagged variables are useful to infer the thermocline depth. • The level in the reservoir and solar irradiance are the most relevant variables. [ABSTRACT FROM AUTHOR]

The subtidal soft-sediment macrobenthos of a residential coastal marina's 25 ha through-flow canal system was investigated in relation to that in the adjacent natural waterways. The marina, developed from a polluted brownfield island in a warm-temperate estuarine bay, straddles the interface between the axial estuarine channel and a smaller backwater creek separating the island from the mainland, one entrance/exit connecting the canals to each water mass. Although they shared a common pool of taxa, an epibenthic cerithioid microgastropod dominated the axial channel as a whole, a subsurface paraonid polychaete likewise the backwater creek, whilst, unusually, sediment/water interface crustaceans dominated the whole marina canal system, especially the amphipods Ampelisca and Grandidierella. In contrast, the abundance of opportunistic annelids in the marina was very low. Whilst coastal marinas have generally been considered ecological disasters, biodiversity in this one's canals was unusually high at 104 observed invertebrate taxa; 97% of those achieving >25 m−2 in the local axial estuarine channel also occurred in the marina, and additionally its canals supported a number of uncommon taxa not otherwise known from the estuarine bay. This South African marina atypically appears to constitute a biodiversity asset, the more valuable because of its brownfield-site origin; and such appropriately constructed and managed through-flow marinas could form potential refuges for threatened estuarine and coastal soft-sediment benthos. It is concluded that only new marinas with a through water flow should be permitted to be located in ecologically sensitive or conservationally important areas and that regular monitoring of soft-sediment benthos should form an essential part of marina management regimes. [Display omitted] • Subtidal soft-sediment macrobenthos of through-flow coastal marina canals studied. • 97% of common taxa in adjacent natural estuarine channel also present in marina. • Unusually, marina-canal benthos dominated by crustaceans, particularly amphipods. • The 25 ha of brownfield canals biodiverse, with >100 invertebrate macrobenthic taxa. • Such coastal marinas could provide refuges for local macrobenthic biodiversity. [ABSTRACT FROM AUTHOR]

Due to its advantages, the air lift pump has many applications in real life. Therefore, the present study is dealing with the effect of some parameters on the air lift pump performance. The present study is a continuation of a program started years ago by the fluid mechanics group in Faculty of Engineering, Alexandria University. Beginning by validating the obtained results of the experiment set-up by comparing these experimental results with international accepted sets of data. After that the present experiments shed some lights on the inlet injection region of the air lift pump due to the significant effect of its initial conditions on the pump efficiency. Thus the study directed towards investigating the effect of some parameters including the inlet restrictor resistance, the injection direction and the injector riser diameter. The upward injection technique shows higher peak efficiency of 34.7% compared to 29.7% and 28.9% for downward and side injection respectively while the larger injector inner diameter shows maximum water capacity of 928 kg/h. compared to 823 kg/h. water mass flow rate for the smaller inner diameter injector. In all the above experimental tests, flow visualization is used extensively giving a good agreement with well recognized flow pattern map. [ABSTRACT FROM AUTHOR]

We investigated the recent spatial variation in the mesozooplankton community on the broad shelf of the RSR MPA during the bloom season. The mesozooplankton community was geographically divided into three regions: the Terra Nova Bay polynya, the Ross Sea polynya, and the marginal polynya. Larval euphausiids were dominant in the two polynya regions, whereas copepods were predominant in the marginal polynya region. Salinity, sea ice, and dissolved oxygen related to the different water mass compositions were the most significant factors distinguishing the mesozooplankton community. The key environmental variable separating the three groups was salinity. In accordance with the relatively high mesozooplankton abundance in the polynya regions, the occurrence and size of the polynyas in the December Ross Sea are thought to affect the spatial distribution of mesozooplankton. Consequently, this study indicates that two polynyas in the Ross Sea are vital habitats for krill during summer. Our observation results provide fundamental information for evaluating marine ecosystems and establishing a management plan for the RSR MPA. [Display omitted] • The Ross Sea continental shelf was divided into the main polynya and marginal polynya regions during the early summer. • The main polynya groups of the RSR MPA were subdivided into the Terra Nova Bay polynya and Ross Sea polynya regions. • Copepods were dominant in the marginal polynya region, whereas larval euphausiids were dominant in main polynya regions. • The mesozooplankton community in the early summer of the RSR MPA was mostly regulated by the formation of polynyas. • The main environmental parameters that distinguished the mesozooplankton community were salinity and sea ice. [ABSTRACT FROM AUTHOR]

A numerical simulation of global heat transfer process in three types of micro-channel heat exchangers was investigated in this paper: spiral double-pipe micro-channel heat exchanger (DPHE), cross-plate micro-channel heat exchanger (CPHE), and shell and tube micro-channel heat exchanger (STHE). The inner tubes of all three heat exchangers have a diameter of 1 mm and are charged with CO2 as refrigerant. A detailed analysis of the heat exchanger's global heat transfer process was carried out, which is entirely different for different structures. The heat transfer characteristics of supercritical CO2 were analyzed by considering the operating pressure, the refrigerant mass flux, the cooling water mass flux, and the heat exchanger refrigerant inlet temperature. The relationship between the CO2 heat transfer coefficient (hCO2) and CO2 bulk temperature (Tb,CO2) was analyzed in detail. The pseudo-critical temperature (Tpc) mainly determines where the peak CO2 heat transfer coefficient occurs. When Tb,CO2 < Tpc, the rise in Tb,CO2 is accompanied by an increase in the heat transfer coefficient, which reaches a maximum when Tb,CO2 is a little bit higher than the pseudo-critical temperature, the heat transfer coefficient curve begins to decline as Tb,CO2 continues to rise. Higher peak heat transfer coefficients can be achieved at higher pressures. Increased refrigerant mass flux always results in larger heat transfer coefficients. The influence of the refrigerant inlet temperature of the heat exchanger in the Tb,CO2 < Tpc region on the heat transfer coefficient is more significant than expected. In this study, different flow patterns on heat transfer due to different structures were compared. The best heat transfer was achieved using a spiral double-pipe micro-channel heat exchanger (DPHE). It consistently reaches the highest heat transfer and the lowest outlet temperature under the same operating conditions‎. [ABSTRACT FROM AUTHOR]

Warm saline water masses emanating from the Persian Gulf (PG) and the Red Sea (RS) spread across a large area of the northern Indian Ocean upper layers, affecting the thermocline stratification, the circulation, and the air-sea exchanges over the Arabian Sea (AS) and Bay of Bengal (BoB). To explore the significance of these waters, we use numerical simulations to investigate the impact of isolating (closing) the RS and PG. The results show that the differences between the model runs, with and without the RS and PG, have marked effects on the AS and BoB seasonal variability. As expected, the major differences are concentrated in the surface mixed layer and thermocline of the AS. However, differences are also found further east in the BoB, mainly during the boreal summer. Significant differences are present in the air-sea freshwater and heat fluxes calculated by the model. In addition to the seasonality, there are significant interannual variability, with possible correlation with the El Nino-Southern Oscillation. Results of the experiments suggest that the upwelling in the Sri Lanka Dome, in the southwestern Bay of Bengal, would have responded differently to the 2009-2010 El Niño-La Niña in the absence of PG and RS input. [ABSTRACT FROM AUTHOR]

Copyright of MESO is the property of Zadruzna Stampa D.D. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tip clearance in hydraulic machines may complicate the fluid-structure interaction (FSI) effects. In this investigation, a mode-based approach (modal work) is evaluated and employed to quantitatively predict the added mass, added stiffness, and hydrodynamic damping ratio, in relation to the first-order bending mode of a vibrating hydrofoil. The investigated relative tip clearance ranges from 0.067% to 2% of the span length. The predicted vortex shedding frequency, natural frequency, and hydrodynamic damping ratio of the hydrofoil are in good agreement with the previously published experimental results, with relative deviations within 9.92%, 6.97%, and 11.23%, respectively. Simulation results show that the added mass, added stiffness, and hydrodynamic damping ratio increase inversely as the tip clearance increases. In particular, as the relative tip clearance increases from 0.067% to 2%, the added mass in still water, the added stiffness, and hydrodynamic damping ratio at a velocity of 10m/s decrease by 18.66%, 9.36%, and 27.99%, respectively. As the tip clearance increases, the inversely increased pressure difference between the upper and lower surfaces of the vibrating hydrofoil is the main reason for the inversely increased hydrodynamic damping ratio. This is due to the energy leakages via the tip clearance region increase as the tip clearance increases, which may cause less fluid force to resist the vibration of the hydrofoil, resulting in less negative modal work done by the fluid load on the hydrofoil. [ABSTRACT FROM AUTHOR]

Self-healing mechanism (SHM) application has attracted interest due to ability to self-heal as response to damage situations in various conditions, and is being actively explored. However, the application of SHM that can be autonomously triggered for temporarily keeping structural integrity of underwater robotic vehicle (URV) under flooding condition is still scarce publicly. This paper describes an investigation in watertight integrity performance of URV's hull under damaged stability criteria. The main goal is to investigate the characterization of a rapid SHM through an experiment for identifying progressive flooding in a damaged URV's hull. Here, it is demonstrated that the effectiveness of sodium polyacrylate, a kind of superabsorbent polymers (SAP), had been studied by applying the polymer on an experimental model of damaged URV's hull. A comparison is studied for the stability of the flooded URV and the mass of water accumulated inside the URV's hull between the cases of before and after applying the SHM in the damaged model under different damaged conditions. The results showed that the SHM application had rapidly blocked the damaged leak hole and prevented severe water flow ingress in the damaged URV's hull. Swift recovery of buoyancy was obtained, as the volume of absorbed water by SHM was converted into equivalent buoyancy loss. These findings are establishing a fundamental knowledge for implementation of SHM in underwater robotic structures. [ABSTRACT FROM AUTHOR]

Capable of retaining rainwater, Organic Ground Cover (OGC) is an ecological material for urban greening. The water absorption features of various OGC materials should be identified before selecting the proper OGC for places under different climates. With the aid of a rainfall simulator, this paper experimentally explores the water absorption features of 16 common OGC materials at the rainfall intensity of 48 mm/h. Based on the experimental results, the change trends of multiple indices were analyzed for these materials, namely, volumetric water absorption ratio, volumetric water absorption rate, mass water absorption ratio, mass water absorption rate, pre-drainage duration, and near saturation duration. The results show that the OGC materials differed significantly in water absorption capacity: (1) SD and PPB2 had the best volumetric water absorption ratios, while EC had the worst volumetric water absorption ratio. (2) The volumetric water absorption rates of all materials reached the maximum in 0–10 min after the artificial rainfall, and then decreased rapidly; At 10 min, the proportion of volumetric water absorption ratios of the 16 materials averaged at 74%; The highest (94%) and lowest (36%) proportions belong to OC and SD, respectively. (3) OC had the best mass water absorption ratio, while EC had the worst mass water absorption ratio. (4) At 10 min, the proportion of mass water absorption ratio of each material was the same as that of volumetric water absorption ratio; OC, PN, CF, CFP, PPB1, WB, and ANBM had obviously higher mass water absorption rates than other materials, while PS, FPB2 and EC had relatively small mass water absorption rates. (5) The shortest and longest pre-drainage durations belong to OC (2 min) and SD (13.67 min), respectively. (6) The shortest pre-near saturation belongs to CFP, PPB1, FPB2 and EC (13.33 min), the longest pre-near saturation belongs to SD (50 min), respectively. The research results provide a reference for the selection of the OGC materials in urban greening. [ABSTRACT FROM AUTHOR]

This paper presents irreversibility analysis using experimental data from vapor compression chiller system using R22, R407C, R404A and R-134A as working fluids. The system operated under cycling condition, which allowing the water to circulate in the evaporator and recording data every ten minutes. Further, the experimental study was conducted at different water and ambient temperature to identify the parameter that cause the energy deterioration. The findings show that the total irreversibility increases at high water mass flow rate. Additionally, high ambient temperature increase the irreversibility of the system. R134A and R407C are a good replacement for R22 in terms of irreversibility analysis during cycling condition. [ABSTRACT FROM AUTHOR]

Biomass cookstoves have been studied extensively for several decades. The Water Boiling Test (WBT) has been a widely adopted protocol for obtaining measurements needed to quantify biomass cookstove performance metrics. WBT metrics have been commonly used to evaluate cookstove effectiveness and serve as a basis for comparing biomass cookstoves. This paper demonstrates the influence of variations in testing parameters on measured or calculated metrics, especially since changes in multiple testing parameters may have competing effects on a given metric. In controlled experiments, this study assessed the effects of variations in the presence or absence of a pot lid, firepower, pot size, the initial mass of water, and presence or absence of boiling on the performance metrics of overall thermal efficiency (η), thermal efficiency associated with heating water (η heat), specific consumption (SC), and the time to reach 90 °C. η was not greatly affected by variations in any of the testing parameters (i.e. no effect was greater than 6% of the base case). SC and η heat , which are interrelated metrics, can provide additional insights on cookstove efficiency. Although these latter metrics showed a wide range of values due to variations in testing parameters, the use of a lid greatly reduced variations in both η heat and SC metrics even when there were significant variations in the other testing parameters. Thus, the use of a lid would provide better consistency for cookstove comparisons when using these metrics. The time to reach 90 °C varied widely among changes in testing parameters. Therefore, this metric is difficult to use for cookstove comparison without strict control of testing protocols. • Overall efficiency is not greatly affected by several testing parameters. • Specific consumption (SC) and η heat are related metrics for cookstove comparison. • A lid greatly reduced variation in both η heat and SC metrics. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Temporal variations in the numbers of foraging seabirds usually coincide with concurrent variations in physical processes influencing prey availability. Responses to periodic tidal currents are commonly reported, with certain tidal states favoured. By contrast, responses to intermittent meteorological events have rarely been reported, even though wind-driven exchanges of water masses or intrusion of estuarine plumes could have similar consequences. As large-scale offshore constructions (e.g., aquaculture, coastal defences, ports and marine renewable energy installations) and climate variations alter periodic tidal currents and intermittent meteorological events, respectively, quantifying responses to these physical processes can identify potential impacts on seabird communities. This study quantifies responses of foraging seabirds to physical processes in the Ria de Vigo, northwestern Spain. The numbers of foraging European Shags Phalacrocorax aristotellis and Yellow-legged Gulls Larus michahellis showed no response to variations in tidal current direction and speed. By contrast, both species increased in number during an estuarine plume intrusion (the Western Iberian Buoyant Plume: WIBP) following an extreme river discharge event and a period of southerly winds. These increases in numbers may be explained by the temporary combination of marine and brackish-water fauna, increasing prey biomass. The frequency of extreme river discharge events is likely to decrease in northwestern Spain. If WIBP intrusions consistently enhance prey availability, observations of large numbers of foraging seabirds using the ria could become rarer. [ABSTRACT FROM AUTHOR]

This study aims at characterizing the hydrodynamic context and transport patterns that prevailed during the MERITE-HIPPOCAMPE cruise to assist in the interpretation of in-situ observations. The main physical attributes and structures (mesoscale eddies as well as fine-scale fronts and filaments) are analyzed based on various physical diagnostics. They were computed from satellite data and data-assimilative model outputs to describe ocean dynamics. The Northern and Algerian Currents were prominent features during the cruise while the western basin is divided by the vertically-tilted Balearic front. Temperature and salinity were used to distinguish different water masses at both surface and sub-surface. Sea-level anomalies, relative vorticity, and Okubo-Weiss parameter distributions have shown the presence of marked eddies around stations St10 and St11. Furthermore, Finite-Size Lyaponuv Exponents revealed that the former was rather located on a fine-scale filament near the edge of a cyclonic eddy while the latter was closer to the core of an anticyclone. Nearshore thermal fronts were detected with the Belkin and O'Reilly Algorithm (BOA), especially around stations St17 and St19. The potential coastal sources of contaminants were tested using Lagrangian Origin Maps (LOM), suggesting that stations St1, St2, St4, St11, and St15 were most likely influenced by coastal waters. Additionally, an atmospheric reanalysis combined with a Lagrangian dispersal model allowed for estimating wet deposition events of contaminants while tracking the fate of water masses where rainfall took place. Finally, we provide a set of explanatory quantitative and qualitative variables for future statistical analyses that aim at explaining the distribution of both chemical and biological samples collected during the cruise. • Synoptic maps from satellite & data-assimilative model contextualize in-situ observations. • Prominent mesoscale eddies in the Algerian sub-basin due to strong instabilities • Narrow jet off French coast & sharp nearshore fronts in Gulf of Gabes • Explore coastal sources & wet deposition of contaminants using a Lagrangian dispersal model [ABSTRACT FROM AUTHOR]

Microplastic pollution has been confirmed in all marine compartments. However, information on the sub-surface microplastics (MPs) abundance is still limited. The vertical distribution of MPs can be influenced by water column stratification due to water masses of contrasting density. In this study, we investigated the vertical distribution of MPs in relation to the water column structure at nine sites in the Kattegat/Skagerrak (Denmark) in October 2020.A CTD was used to determine the stratification and pycnocline depth before sampling. Plastic-free pump-filter sampling devices were used to collect MPs from water samples (1–3 m3) at different depths. MPs concentration (MPs m−3) ranged from 18 to 87 MP m−3 (Median: 40 MP m−3; n = 9) in surface waters. In the mid waters, concentrations ranged from 16 to 157 MP m−3 (Median: 31 MP m−3; n = 6), while at deeper depths, concentrations ranged from 13 to 95 MP m−3 (Median: 34 MP m−3; n = 9). There was no significant difference in the concentration of MPs between depths. Regardless of the depth, polyester (47%), polypropylene (24%), polyethylene (10%), and polystyrene (9%) were the dominating polymers. Approximately 94% of the MPs fell within the size range of 11–300 μm across all depths. High-density polymers accounted for 68% of the MPs, while low-density polymers accounted for 32% at all depths. Overall, our results show that MPs are ubiquitous in the water column from surface to deep waters; we did not find any impact of water density on the depth distribution of MPs despite the strong water stratification in the Kattegat/Skagerrak. [Display omitted] • Microplastics (MPs) were ubiquitous in the water column of the Kattegat/Skagerrak. • The median concentration of MPs in the water column was 35 MPs m−3. • Small MPs (<100 μm) of high-density polymers were dominant in the water column. • No significant difference in MPs concentration among water layers was found. [ABSTRACT FROM AUTHOR]

Radioactive cesium (137Cs) is distributed in the world's oceans as a result of global fallout from atmospheric nuclear weapons tests, releases from fuel reprocessing plants, and inputs from nuclear power plant accident. In order to detect future radionuclide contamination, it is necessary to establish a baseline global distribution of radionuclides such as 137Cs and to understand the ocean transport processes that lead to that distribution. In order to aid in the interpretation of the observed database, we have conducted a suite of simulations of the distribution of 137Cs using a global ocean general circulation model (OGCM). Simulated 137Cs radioactivity concentrations agree well with observations, and the results were used to estimate the changes in inventories for each ocean basin. 137Cs activity concentration from atmospheric nuclear weapons tests are expected to be detectable in the world ocean until at least 2030. [Display omitted] • The global 137Cs distribution was simulated by multiple sources and compared to available observations. • Simulated results were generally in good agreement with the database. • Changes in inventories and flux between ocean basins are summarized. • The impact of global fallout will continue to be detectable and could be a useful water mass tracer for ocean circulation and mixing studies. [ABSTRACT FROM AUTHOR]

Kelp forests, globally distributed in cool temperate and polar waters, are renowned for their pivotal role in supporting species diversity and fostering macroalgae productivity. These high-canopy algal ecosystems dynamically influence their surroundings, particularly by altering the physicochemical properties of seawater. This review article aims to underscore the significance of kelp forests in modifying water masses. By serving as effective carbon sinks through the absorption of bicarbonate (HCO 3 −) and carbon dioxide (CO 2) for photosynthesis, kelp forests mitigate nearby acidity levels while enhancing dissolved oxygen concentrations, essential for sustaining diverse marine communities. Additionally, kelp beds have exhibited the need to use inorganic ions (NO 3 −, NO 2 −, PO 4 3−) from seawater in order to grow, albeit with associated increases in NH 4 + concentrations. Specific examples and findings from relevant studies will be presented to illustrate the profound impact of kelp forests on seawater chemistry, emphasizing their vital role in marine ecosystems. [Display omitted] • Kelp forests are known as key habitats for species diversity. • Kelps contribute to physicochemical modifications of the marine environment. • Kelps alter light, abrasion, nutrients presence, sedimentation and flow dynamics. • Kelp forest is able to drive fluctuations in the chemical composition of seawater. • Climate change may have an impact on kelps' ability to modify the environment. [ABSTRACT FROM AUTHOR]

The potentially toxic elements (PTEs), Cu, Pb, Zn, Cd, Cr, Hg and As in the water from the Beibu Gulf, were investigated to reveal the contaminant characteristics and assess the risks to human health. The results showed that the concentration of PTEs in the Beibu Gulf varies significantly both seasonally and spatially, with higher concentrations in summer and in the northern and southern gulf. Terrestrial inputs and local anthropogenic discharge are responsible for the higher level in the northern gulf, and the transportation of water masses is also an important factor for the higher concentrations in the southern gulf. Ecological risk assessment suggested that Hg is the main ecological risk factor. The health risk assessment revealed that dermal exposure to PTEs in the gulf presents potentially carcinogenic health effects for humans. This study provides new insight into the transport of PTEs over a large area of the Beibu Gulf. • PTEs (Cu, Pb, Zn, Cd, Cr, Hg and As) in the water column of the large area of Beibu Gulf were investigated. • The distributions of PTEs varied significantly both seasonally and spatially. • Hg is the main factor for the potentially ecological risk in the seawater. • Dermal exposure to PTEs in the gulf presents potentially non-carcinogenic and carcinogenic health effects for human. [ABSTRACT FROM AUTHOR]

This paper focuses on the user rights regimes that have governed access to the marine resources of the Faroe Islands, which in the case of the fisheries are primarily fish stocks, and, in the case of salmon farming, primarily clean and healthy water masses. Examining the application of different user rights arrangements, we were able to observe a gradual improvement in the economic efficiency of the production activity for salmon farming, where strong operating exclusivity played a pivotal role in strengthening user rights. Similarly, the pelagic fisheries and the distant-waters demersal fisheries governed by ITQs have witnessed improved economic efficiency, although the strength of their user rights weakened over the last decade because of diminishing exclusivity and security of their rights. At the same time, the coastal demersal fisheries governed by ITEs continued to be marked by overcapacity and low fish stock levels despite the presence of strong exclusivity. These findings indicate that the design of user rights must also relate to specific management differences in marine resource exploitation under consideration. [ABSTRACT FROM AUTHOR]

Abstract The abundance and species composition of Parmales (Bolidophyceae), a siliceous marine phytoplankton, were investigated in the waters surrounding Hokkaido, North Japan. In the Pacific Ocean, high Parmales abundances were observed in the Oyashio region (84.9–95.2 cells mL−1), in the surrounding area of the cold Oyashio Current, and in the Coastal Oyashio Water (35.1–41.4 cells mL−1) being low temperature and salinity in spring. In the Okhotsk Sea, Parmales abundance was moderate (>5 cells mL−1) in the Intermediate Cold Water, which is formed by convective mixing under the pack ice. On the other hand, their abundance was quite low in warm water masses, such as the Tsushima Warm Current in the Sea of Japan and the Soya Warm Current in the Okhotsk Sea. Parmales cells were also found in the sea ice in the Notoro-ko Lagoon connected to the Okhotsk Sea, suggesting that they have an ice algal life cycle. Triparma spp. were almost dominant in the study areas with the occasional contribution of Tetraparma spp. in the Okhotsk Sea. These results indicate that Parmales abundance and species composition are significantly influenced by water currents. [ABSTRACT FROM AUTHOR]

A butterfly type of repeat track cruise was carried out in the South Eastern Arabian Sea (off Minicoy) onboard INS Sagardhwani during July 2016 to Aug 2016. We have also made use of the data from OMNI buoy, AD09, which is about 6 km close to the centre station of butterfly track. Air sea flux, the horizontal current data from AD09 and the time series data collected from the butterfly experiment were analysed to compute the mixed layer heat and salt budget. The short-term thermo-haline variability off Minicoy, relative contribution of heat/salt budget terms in MLD and its effects on acoustic propagation are addressed in this paper. In this study, most dominating term in the mixed layer heat budget estimation is net surface heat flux followed by the advective terms has been found. However the salinity in the mixed layer is dominated by the contribution of buoyancy mixing due to night time evaporative cooling. During the calm, sunny day, the so-called afternoon effect due to the diurnal heating restricts the sonar range. But during the windy day, the wind/wave mixing prevents the warming of the surface layer which in turn enhances the sonar range. Similarly, the night time cooling also enhance the acoustic propagation range. The presence of Arabian Sea High Salinity Watermass in the surface layer also enhances the acoustic propagation. [ABSTRACT FROM AUTHOR]

Intra-annual variability of the Arabian Sea high salinity water mass (ASHSW) in the South Eastern Arabian Sea (SEAS) and Gulf of Mannar (GoM) are addressed in this paper by utilising the monthly missions carried out onboard INS Sagardhwani during 2016-17. Our observations revealed that the ASHSW was evident along the SEAS irrespective of seasons, whereas in the GoM the presence of ASHSW was observed during winter. The processes such as downwelling/up-welling, coastal currents, intrusion of low saline waters, stratification are clearly affect the spreading of the ASHSW. The characteristics such as core salinity value, depth and thickness of ASHSW exhibited remarkable spatio-temporal variability. Lateral mixing with the low saline waters in the region during winter reduces its core salinity. The intrusion of low saline waters was clearly seen upto 15 °N but the intrusion of low saline waters is not flowing through the GoM. The interface between the ASHSW and the prevailing low saline waters showed strong horizontal gradients of salinity. The presence of the ASHSW makes difference in the SLD and the below layer gradient which is sufficient to complicate or influence sound transmission. The spatio temporal variability of the ASHSW and its acoustic relevance are documented in this paper. [ABSTRACT FROM AUTHOR]

Mesoscale eddies have been reported to have a substantial impact on the distribution of phytoplankton through the regulation of environmental variables in the open ocean. However, the influence of warm eddies on phytoplankton in continental slopes remains largely unknown. To reveal the impact of mesoscale eddies within slope regions, we conducted a field investigation of picophytoplankton on the northern slope of the South China Sea during an anticyclonic warm eddy propagation. We observed different picophytoplankton distribution patterns. Synechococcus dominated the picophytoplankton community in the Kuroshio-affected eddy core rather than the previously reported Prochlorococcus , and Prochlorococcus dominated outside the eddy in the shelf. In addition, through further vertical study of typical layers, we found that the influence of warm eddy varied in different layers. Analysis of the mechanisms indicated that the distributions were attributed to warm eddy-induced nutrients and light variations and the physical processes in it. [Display omitted] • Analysis of warm eddy impacts on picophytoplankton in South China Sea slope area • Different distribution pattern of picophytoplankton was observed. • The warm eddy changed the distribution of nutrients and light intensity. • The warm eddy affected the composition of water masses. • The distribution of picophytoplankton was influenced by physical-chemical variations. [ABSTRACT FROM AUTHOR]

This study aimed to assess the extent of eutrophication in the Marchica lagoon, using the trophic index (TRIX), trophic status index (TSI) and Redfield ratio (N/P). Seawater samples were collected monthly from March 2018 to February 2019 from ten locations in the lagoon. The TRIX index ranged from 1.25 to 8.87, indicating oligotrophic to eutrophic conditions. TSI values ranged from 28.4 to 65.1, indicating ultraoligotrophic to supereutrophic seawater. The Redfield ratio consistently showed N/ P values below 16, designating phosphorus as the limiting factor for algal growth. Principal component analysis (PCA) and cluster analysis (CA) revealed distinct coastal water masses based on seasons and sampling regions. Given these findings, urgent conservation and management measures are recommended to address the eutrophication issues threatening the delicate balance of the Marchica lagoon. • Study assesses eutrophication and trophic status of Marchica lagoon using TRIX and TSI indices. • Principal component and cluster analyses distinguish water quality near southern continental margin. • Trophic state of lagoon seawater varies from oligotrophic to eutrophic. • The current state of the lagoon requires serious interest, given its vulnerability and fragile balance. [ABSTRACT FROM AUTHOR]

Mesoscale eddies have been reported to have a substantial impact on the distribution of phytoplankton through the regulation of environmental variables in the open ocean. However, the influence of warm eddies on phytoplankton in continental slopes remains largely unknown. To reveal the impact of mesoscale eddies within slope regions, we conducted a field investigation of picophytoplankton on the northern slope of the South China Sea during an anticyclonic warm eddy propagation. We observed different picophytoplankton distribution patterns. Synechococcus dominated the picophytoplankton community in the Kuroshio-affected eddy core rather than the previously reported Prochlorococcus , and Prochlorococcus dominated outside the eddy in the shelf. In addition, through further vertical study of typical layers, we found that the influence of warm eddy varied in different layers. Analysis of the mechanisms indicated that the distributions were attributed to warm eddy-induced nutrients and light variations and the physical processes in it. [Display omitted] • Analysis of warm eddy impacts on picophytoplankton in South China Sea slope area • Different distribution pattern of picophytoplankton was observed. • The warm eddy changed the distribution of nutrients and light intensity. • The warm eddy affected the composition of water masses. • The distribution of picophytoplankton was influenced by physical-chemical variations. [ABSTRACT FROM AUTHOR]

This study aimed to assess the extent of eutrophication in the Marchica lagoon, using the trophic index (TRIX), trophic status index (TSI) and Redfield ratio (N/P). Seawater samples were collected monthly from March 2018 to February 2019 from ten locations in the lagoon. The TRIX index ranged from 1.25 to 8.87, indicating oligotrophic to eutrophic conditions. TSI values ranged from 28.4 to 65.1, indicating ultraoligotrophic to supereutrophic seawater. The Redfield ratio consistently showed N/ P values below 16, designating phosphorus as the limiting factor for algal growth. Principal component analysis (PCA) and cluster analysis (CA) revealed distinct coastal water masses based on seasons and sampling regions. Given these findings, urgent conservation and management measures are recommended to address the eutrophication issues threatening the delicate balance of the Marchica lagoon. • Study assesses eutrophication and trophic status of Marchica lagoon using TRIX and TSI indices. • Principal component and cluster analyses distinguish water quality near southern continental margin. • Trophic state of lagoon seawater varies from oligotrophic to eutrophic. • The current state of the lagoon requires serious interest, given its vulnerability and fragile balance. [ABSTRACT FROM AUTHOR]

Abstract Numerical experiments using a 3D model of fine sediment transport in the Great Barrier Reef region indicate deposition of the bulk mass of catchment sediments from river plumes within a few tens of kilometres from river mouths. A very fine fraction of easily resuspended catchment sediment has a capacity to propagate over much greater distances reaching out into the mid-shelf and outer-shelf regions. The model suggests such particles, instrumental to the development of low density flocs in the marine environment, can play a critical role in altering optical properties of water masses over the shelf during wet years. The mid-term (4 year) impact of Great Barrier Reef catchments on the probability of suspended sediment concentration exceeding the ecologically significant trigger value of 2 mg/L is confined to inshore regions adjacent to river mouth locations. Highlights • A bulk mass of catchment sediments in the GBR region deposits within a few tens of kilometres from river mouths. • A very fine fraction of catchment sediment has a capacity to alter optical properties of water masses over the shelf. • The impact of GBR catchments on the probability of suspended sediment exceeding 2 mg/L is confined to inshore regions. [ABSTRACT FROM AUTHOR]

Temperature, salinity and density time series provided by Izmir Bay monitoring studies are analyzed in order to examine the periods especially involving the EMT and EMT-like events causing big change in the water characteristics of the Aegean Sea. The main objective of this study is to find out the indication of these events in the Izmir Bay by analyzing the available oceanographic datasets for the period of 1991-2017 and to show the parallelism consisting between the isopycnal levels in the Izmir Bay and the phases of the upper layer circulation of the Ionian Sea. 1993 (EMT event), 2007-2009 (EMT-like event) and 2012 (abrupt reversal) are the years that high isopycnal levels were observed in the Izmir Bay and concurrently the upper layer circulation of the Ionian Sea was in anti-cyclonic phase. The important and remarkable thing is that such EMT and EMT-like or abrupt reversal events can be detected from the observations conducted in the bays and coastal area of eastern Aegean Sea. [ABSTRACT FROM AUTHOR]

Replacement of the warm water of the Soya Warm Current (SWC) and the cold water of the East Sakhalin Current (ESC) occurs seasonally along the coast of the southwestern Okhotsk Sea, and sea ice covers the surface during winter. Pseudocalanus newmani is one of the dominant copepods in coastal waters of the northern hemisphere. To better understand the population dynamics of the copepod P. newmani in coastal areas of the southwestern Okhotsk Sea, this study compared the seasonal variation in P. newmani abundance in Lagoon Notoro-ko and a coastal area of the Okhotsk Sea with regard to developmental stage. We sampled P. newmani in the lagoon, including during the ice cover season, and the coastal waters. Pseudocalanus newmani was abundant at both sites in spring. During summer–fall, adults disappeared from the populations at both sites, whereas the early developmental stages were abundant and dominated the population. Total length of adult females decreased toward summer at both sites. Pseudocalanus newmani abundance in the lagoon increased in early winter, and larger females were found in the populations at both sites. These phenomena at both sites corresponded with seasonal variation in water temperature caused by seasonal water-mass replacement and sea ice. [ABSTRACT FROM AUTHOR]

The discharge of petroleum hydrocarbons (PHs; ~ 10,000 tons annually) into the Bohai Sea, a shallow inland sea in China, presents a serious threat to the marine environment. To evaluate the effects of PHs pollution and estimate the corresponding environmental capacity, we have developed a genetic algorithm-based coupled hydrodynamic/transport for simulating PHs concentration evolution and distribution from July 2006 to October 2007, with the predicted values being in good agreement with monitoring results. Importantly, the mean PHs concentrations and seasonal concentration variations were primarily determined by external loading, i.e., currents were shown to drive PHs transport, reconfigure local PHs patterns, and increase PHs concentration in water masses, even at large distances from discharge sources. The developed model could realistically simulate PHs distribution and evolution, thus being a useful tool for estimating the seasonal environmental capacity of PHs. [ABSTRACT FROM AUTHOR]

This work is an overview of all available benthic data collected in the Algerian harbours between 1983 and 2001. So, total of 571 stations were reported in the 10 major Algerian harbours along the Algerian coast (1200 km). Two main categories of harbours were distinguished according to their hydrodynamic regime and volume of water exchange between inner harbour basins and the entrance of the harbours. Univariate, multivariate, benthic indices and Biological Traits of Life approaches were applied on stations sampled in the late 1990s and long-term observations in six out of these ten harbours. These approaches assessed the main characteristics and ecological statuses from these south Mediterranean harbours. One of the main characteristics of the Algerian harbours was the very high species diversity (847 species). Although all the fauna was dominated by pollution-tolerant species; some harbours such as Bethioua and Djendjen hosted normal benthic communities as found in the open sea, but also included some pollution indicator species typical of a slight polluted system. On the contrary, the newly constructed port of Skikda showed perturbed benthic communities in relation to hydrocarbon pollution. Biological Traits of Life analysis reinforced the separation of benthic species along a gradient reflecting their sensitivity or tolerance to pollution. This response was related to an increase in organic matter content, probably associated with a general organic and metal contamination, from the entrance of the harbour to the innermost basins in areas with weak circulation, high sedimentation rate and concentrations of pollutants. Except for Oran harbour, where the poor to moderate ecological status remained unchanged with time, the other harbours showed an improvement or a slight degradation. A strategy of long-term monitoring should be promoted, based on a restricted and selected number of stations characteristic of the different basins and water masses occupying the harbours. [ABSTRACT FROM AUTHOR]

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• The relationship between pH and pO 2 is investigated for ocean water masses. • pH and pO 2 are poorly correlated in Arctic water masses. • Hydrothermal vents affect the chemistry of a large portion of the water column. • The findings have implications for the planning of GCS leakage monitoring. In the absence of abiotic sources of CO 2 , variation in pCO 2 and pO2 is expected to be inversely correlated in the water column due to biogenic processes. It has previously been suggested to use this correlation for leakage monitoring of offshore geological carbon storage (GCS) sites. In this study the aim is to investigate the extent of this correlation in ocean water masses with different origin and history in the Norwegian Sea, as well as in water masses in the vicinity of an active hydrothermal vent field at Mohn's Ridge, where pH is used as a proxy for pCO 2. Over a hydrothermal vent site, a strong correlation between pH and pO2 is observed from 0 to 1700 m, whereas at depths >1700 m there is no correlation, likely due to CO 2 emissions from the hydrothermal vents. However, at a reference site nearly 200 km from the hydrothermal vents, the intermediate Arctic water masses (700 – 1600 m depth) also show pH-pO2 correlations that are inconsistent with biogenic processes, but less pronounced compared to the hydrothermal vent site. These findings show that the suitability of this monitoring strategy will depend on a thorough site-specific evaluation of pH/CO 2 and O2 relationships of relevant water masses. [ABSTRACT FROM AUTHOR]

Ports are complex environments due to their complicated geometry (quays, channels, and piers), the presence of human activities (vessel traffic, shipyards, industries, and discharges), and natural factors (stream and torrent inputs, sea action, and currents). Taking these factors into consideration, we have examined the marine environment of a port from the point of view of the circulation of the water masses, hydrological characteristics, distribution of the sediment grain-size, mineralogical characteristics, and metal concentrations of the bottom sediments. Our results show that, in the case of the Port of Genoa (north-western Italy), the impact of human activities (such as a coal power-plant, oil depots, shipyards, dredging of the bottom sediments, etc.), natural processes (such as currents, fresh water and sediment inputs from the torrents), and the morphology of the basin, are important factors in the sediment, water, and metal distributions that have given rise to a complex environment. [ABSTRACT FROM AUTHOR]

In La Paz Bay conspicuous macroalgal blooms of Ulva spp. are recurrent in the waterfront of the city; studies relate its growth to seasonality and nutrient enrichment but their relative influence is not known. We use the δ 15 N to discern amongst nitrogen sources at three sites with different substratum and anthropogenic activities. Ulva blooms were monitored monthly at San Juan de la Costa (SJC), Casa del Marino (CM) and El Tecolote (TE). Species presence varied between sites and months. At SJC Ulva displayed the highest signal of δ 15 N associated with fishing products and local mining wastewaters (19.5‰). CM showed isotopic values related to sewage waters (13‰). The δ 15 N of species at TE were the lowest. We found higher isotopic signatures than in other tropical/subtropical regions, associated with nutrient rich water masses. Ulva species can be used to trace and discern amongst different sources of nitrogen from natural or anthropogenic sources. [ABSTRACT FROM AUTHOR]

The present study reports high inter-annual variability in the water masses and in the intrusion of Atlantic origin waters in Kongsfjorden from 2000 to 2013 using both the historical (2000–2010 summers) and recent CTD measurements (2011–2013 summer/fall). An earlier intrusion of Atlantic Water (AW) into Kongsfjorden was observed in the contemporary years. An overall summertime subsurface warming is evident from the maximum September AW temperature in 2011 (4.8 °C), 2012 (5.8 °C) and 2013 (7 °C). The combination of a compensating surface flow to the subsurface intrusion of AW and the strong southeasterly surface winds during the peak summer, resulted in a corresponding net outflow of the surface fresh water layer from Kongsfjorden. This led to the decreased freshwater volume inside the fjord during 2013 (1 km 3 ) compared to 2011 (3.1 km 3 ) and 2012 (2.3 km 3 ). [ABSTRACT FROM AUTHOR]

The spatial and temporal variations of mesozooplankton in relation to environmental parameters were investigated in the Persian Gulf and the Gulf of Oman. For this purpose, the physicochemical parameters were measured using a CTD probe and mesozooplankton were sampled vertically using a closing net aboard the RV Persian Gulf Explorer during two expeditions. Results showed a relationship between mesozooplankton assemblages and water mass distributions. Four mesozooplankton cluster station groups divided the sampled stations into masses, which was also confirmed by the PERMANOVA test. Overall, ninety taxa were identified that were dominated by copepods and characterized by small cyclopoids. Based on the results the mesozooplankton communities of the Persian Gulf and the Gulf of Oman are mostly shaped by the combined effect of temperature, salinity, and dissolved oxygen that significantly influences mesozooplankton occurrence during summer and spring. • The effects of water masses on the mesozooplankton communities in the Persian Gulf and the Gulf of Oman were investigated. • Environmental parameters revealed four main water masses in the study area: (1) Western Persian Gulf Waters (WPGW), (2) Middle Persian Gulf Water (MPGW), (3) Eastern Persian Gulf Water (EPGW), and (4) the Gulf of Oman Waters (GOW). • Overall, ninety taxa were identified that were dominated by copepods at all stations and characterized by small cyclopoids. [ABSTRACT FROM AUTHOR]

Resting cysts of dinoflagellates seed harmful algal blooms (HABs) and their geographic expansion, which makes it fundamentally important to obtain comprehensive inventories of dinoflagellate resting cysts in HABs-prone regions. The Yellow Sea (YS) of China has observed numerous outbreaks of dinoflagellate HABs with some novel species recorded recently indicating an underestimated HABs-causing species diversity. We report our investigation of dinoflagellate cysts of YS via an approach combining metabarcoding sequencing and single-cyst morpho-molecular identification, which identified many novel cyst species and a significant controlling effect of the Yellow Sea Cold Water Mass on cyst composition. The metabarcoding and single cyst-based sequencing detected 11 cyst species never being unambiguously reported in China, 10 never reported as cyst producers, and 3 HABs-causing species never reported from YS. Our detections of many potentially toxic or HABs-causative, particularly novel, cysts and distribution pattern provide important insights into the risks and ecology of dinoflagellate HABs. [Display omitted] • Many novel and important dinoflagellate resting cysts identified from Yellow Sea, China. • Detected 11 and 10 species of cysts having not been confirmed presence from China and as cyst producers, respectively. • Cyst distribution patterns differed between the offshore and nearshore areas. • The Yellow Sea Cold Water Mass observed to affect the species composition of dinoflagellate cysts. • Longitude, latitude, temperature, salinity, and water depth all affected cyst distribution pattern. [ABSTRACT FROM AUTHOR]

Polar regions are recognized as final sinks of the persistent contaminants, however, environmental investigations in the Antarctica are greatly limited by harsh field conditions. In this study, seawater samples were collected in the Antarctic marginal seas during the austral summer of 2021 to investigate the environmental behavior and fate of organochlorine pesticides (OCPs). The concentrations and source markers of representative legacy hexachlorocyclohexane (HCH), hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethanes (DDTs) indicated the coexistent sources of historical residues and fresh inputs. While the emerging OCPs, including quintozene, pentachloroaniline and dichlobenil, showed relatively lower detection frequency. Due to the differences in temperature and sea ice coverage, dissolved OCPs generally displayed higher concentrations in the eastern Antarctic than those in the western Antarctic. The 'surface depleted and depth enrichment' vertical profile of representative OCPs in the continental shelf of Prydz Bay was jointly controlled by biological pump and water mass structure. • Legacy and emerging organochlorine pesticides were detected in the Antarctic marginal seas. • Relatively higher concentrations of pollutant were displayed in the eastern Antarctic. • Legacy organochlorine pesticides came from both fresh inputs and historical releases. [ABSTRACT FROM AUTHOR]