The concept of the "Southern European Seas"—a term originally introduced by Prof. Özsoy—has since evolved into a focal region for integrated, interdisciplinary research spanning a broad spectrum of spatial and temporal scales. Investigations now range from high-frequency extreme meteo-oceanographic events to long-term climate projections, encompassing the continuum from open ocean to land-coast-river interfaces. Central to these efforts is the development and sustained operation of basin-scale observing systems, the incorporation of citizen science initiatives, state-of-the-art analysis and reanalysis systems, and the application of advanced data-driven and AI-based models for phenomena such as wave dynamics and sea-level variability.
We invite contributions that address these innovative research directions within the Mediterranean, Marmara, and Black Seas. Submissions may include novel methodologies in physical and biogeochemical monitoring, advancements in ocean interdisciplinary modeling, understanding of the short and long-term variability and processes occurring in the Seas, developments in operational oceanography, and the creation of downstream applications and products.
The Southern European Seas -encompassing the Mediterranean Sea, the Sea of Marmara, and the Black Sea- constitute a dynamically coupled system in which basin-scale circulation, strait exchange, stratification, and atmospheric forcing interact across a wide range of spatial and temporal scales. My talk revisits the physical oceanography of “Seas of the Old World” through the scientific contributions of Prof. Emin Özsoy. His work has been central to framing these marginal seas as an integrated dynamical continuum rather than isolated basins beginning with his seminal contributions to POEM early in his career.
This talk focuses on the Eastern Mediterranean and the Black Sea with emphasis on the interbasin exchange processes, particularly within the Turkish Straits System, where two-layer flows regulate mass, salt, and heat budgets. The talk synthesizes observational and modeling studies that elucidate the role of density-driven circulation, pycnocline dynamics, and topographic constraints in shaping water mass transformation, ventilation pathways, and basin-wide circulation. Seasonal to interannual variability associated with atmospheric forcing, buoyancy fluxes, and mesoscale activity is discussed in the context of coupled strait-basin dynamics. By interpreting observations and high-resolution numerical models together, Özsoy’s framework provides a basis for understanding multi-scale dynamics in our regional seas.
This talk argues that the Southern European Seas represent a natural laboratory for studying strait hydraulics, thermohaline circulation, and boundary-dominated ocean dynamics, and calls for sustained, cross-basin observing and modeling strategies to advance predictive capability in complex regional systems.
How to cite: Aydogdu, A.: On the Physical Oceanography of the Southern European Seas: A Perspective Inspired by Prof. Emin Özsoy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10214, https://doi.org/10.5194/egusphere-egu26-10214, 2026.
The Mediterranean Sea climate is undoubtedly changing at unprecedented rates, affecting its surface, shelf regions, intermediate waters, and even its deepest layers and dense water formation sites. Beyond physical changes, the impacts on biogeochemical processes and living organisms remain poorly understood and—despite existing regional climate projections—are largely unknown in terms of how they will respond to ongoing physical transformations. Here, we present several cases that reveal recent physical changes occurring in the Mediterranean Sea. These are based on observations from coastal and deep-sea observatories, opportunistic sampling, long-term ocean stations with nearly centennial time series, and modern observing platforms such as Argo profiling floats. At the surface, we document a widespread occurrence of salinity maxima, not only in the Levantine Basin but across all Mediterranean basins. The second example describes a paradigmatic shift in the properties of North Adriatic Dense Water, with much warmer and saltier waters now occupying the bottom of the Adriatic Sea. Dense-water formation has become predominantly haline-driven, while wintertime cooling now plays a reduced role in dense water cascading. A lack of precipitation and changes in precipitation regimes in the Alpine region have led to higher-than-average salt accumulation in the shallow northern Adriatic. This affects not only dense-water formation but also the summertime spreading of freshened waters—primarily of Po River origin—off the western Adriatic coastline, accelerated in the situations of stronger stratification. In case of warmer surface ocean during late spring and summer as in 2024, such rapid spreading might result in occurrence of extensive mucilage events. Salinity positive shifts have also occurred in the Eastern Mediterranean following the winter of 2022, superimposed on the steadily increasing salinity observed during the Argo era. Many of these physical changes are not adequately captured by climate models, that is, they are not projected to occur at the rates observed. This raises the question of whether current projections remain valid and how they might be improved. In this context, we discuss our findings and outline possible pathways for future research.
How to cite: Vilibić, I. and Terzić, E.: A changing Mediterranean Sea climate: do we know where we are heading?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2535, https://doi.org/10.5194/egusphere-egu26-2535, 2026.
Global climate models struggle to accurately represent the dynamics of the Black Sea because it's so isolated from the open ocean, connected only by the narrow Turkish Straits. To overcome this limitation and study how the Black Sea will be affected by future climate change, we need to use high-resolution regional models. We've developed a new 5km resolution regional model of the Black Sea using the NEMO 4.2.1 ocean circulation model. To validate our new model, we compared it against a well-established 2.5-km resolution model from the Copernicus Marine Service model setup. Both models share the same numerical core, vertical layers, horizontal and vertical parameterizations.
In our first comparison, we used historical ERA5 atmospheric data from 1980 to 2015. The new 5km model performed very well, with biases that were remarkably similar to those of the higher-resolution 2.5-km model. While the 2.5-km model revealed finer details like the Batumi Gyre and specific features near the Crimea Peninsula, both models provided comparable results for deep-ocean dynamics. This confirms that our 5-km model is reliable enough for long-term climate simulations.
Next, we simulated three different future climate scenarios—RCP2.6, RCP4.5, and RCP8.5—using atmospheric data from the 0.01 degree CNRM-ALADIN model in the CMIP5 CORDEX-Europe project. All three scenarios show that the Black Sea surface will get warmer and saltier. In the model simulations, the surface temperature increases 1.5, 2.0, 3.5 degrees between different RCP scenarios respectively, and also gets saltier up to 3 psu. Notably, the Cold Intermediate Layer (CIL), a distinct oceanographic feature which is characterized by a layer of relatively cold water is projected to disappear after 2040 in the RCP8.5 scenario. The warming isn't limited to the surface; it penetrates deep, reaching down to 700 meters. Likewise, the Black Sea is becoming saltier, with this salinification also extending to 700 meters. To increase the robustness of our findings, we also performed an additional RCP8.5 simulation using a different atmospheric model, the SMHI-RCA4 from the CMIP5 CORDEX-Europe project. This ensemble approach helps us account for model uncertainties and strengthens our confidence in the projected climate changes for the Black Sea.
These findings suggest that under a high-emission scenario like RCP8.5, the Black Sea's temperature and salinity profiles will change dramatically. These changes could significantly alter its circulation patterns, stratification, and overall ecosystem dynamics.
How to cite: Ilicak, M. and Tutak, B.: Projecting the Impact of Climate Change on the Black Sea: A High-Resolution Regional Modeling Study, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2209, https://doi.org/10.5194/egusphere-egu26-2209, 2026.
The Black Sea is a large marginal European sea with a unique biogeochemical feature of complete anoxia below 200 m depth. Past studies have also found surface dissolved inorganic carbon (DIC) concentrations and total alkalinity (TA) much above typical global ocean values. Despite the acknowledged importance of shelf areas in global carbon cycle assessments and the uniqueness of this environment, the Black Sea remains a poorly observed region for surface measurements of the partial pressure of carbon dioxide (pCO2). Here, we close this observational gap and provide an updated assessment of the Western Black Sea shelf carbonate system by using two years of data from a new coastal observing station, established in 2022 within the Helmholtz Association European Partnership SEA-ReCap project, and equipped with a FerryBox. Additional measurements with small boat and research cruise surveys provide a comprehensive analysis of the biogeochemical variability in the Western Black Sea region, with some significant anomalous events. We find the typical annual cycle of seawater pCO2 is largely temperature-driven, with monthly averages ranging between 340 and 500 µatm. The region alternates between a carbon source/sink status, but overall there is an efflux to the atmosphere of 2.2 ± 6.7 mmol C m-2 day-1. Superposed on the typical cycle, we observed strong non-thermal anomalous events. Examples are low-salinity water influx driving new biological production, with an associated drop in seawater pCO2 to below 200 µatm, or coastal upwelling bringing bottom shelf water low in oxygen and high in DIC to the surface, raising the pCO2 to above 800 µatm. Using the similarities between the observations at the coastal station and those we performed on the moving vessels, we were able to calculate a regionally integrated air-sea exchange component of the carbon budget. The restricted Western Black Sea shelf emitted 0.012 Tg C to the atmosphere during a regular year, while during an anomalous year, this amount increased to 0.020 Tg C. Finally, we used a robust relationship between laboratory measured samples of DIC and TA from the research cruise and calculated values from underway pCO2 and pH measurements to create quasi-continuous time series of all carbonate system parameters at the coastal station. These results and the sustained monitoring at the coastal station will help us assess the region’s resilience to climate and anthropogenic forcings, as we have been able to demonstrate in parallel studies on extreme storms in this region we captured in 2023.
How to cite: Macovei, V., Slabakova, V., Drumeva, N., and Voynova, Y.: The carbonate system in the Western Black Sea Shelf: new observations reveal drivers of carbon source/sink variability, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12600, https://doi.org/10.5194/egusphere-egu26-12600, 2026.
With increasing air and water temperatures, storms are likely to increase in frequency and magnitude, especially in semi-enclosed basins like the Black Sea, where recent estimates show that surface sea water temperatures have increased between 0.06-0.1 degrees per year over the past two decades. During the fall season of 2023, the Black Sea and especially the northwest shelf region experienced several storms, like Storm Daniel, which caused major oxygen deficit in surface waters in September 2023, and two major November storms, Frederico and Bettina, associated with the highest winds (>20 m s-1) over the past 5 years. Using a continuous pCO2 record from a coastal station established in summer 2022, supported by the Helmholtz Association European Partnership project SeaReCap, we identify large-scale sea-air CO2 fluxes (>800 mmol C m-2 month-1) to the atmosphere (3 times more than other months with positive fluxes) in November 2023. Compared to 2024 when sea-air flux is negative, both November and December of 2023 are large net sources of CO2 to the atmosphere. This is due to both upwelling favorable conditions at the end of October, bringing bottom water enriched in carbon to the surface after a productive summer, and to increased mixing in November from the two storms. With increasing temperatures, these large and extreme storms are likely to continue to have an impact on the Black Sea sea-air CO2 flux.
How to cite: Voynova, Y., Slabakova, V., Macovei, V.-A., Drumeva, N., Neumann, A., Gramcianinov, C., and Staneva, J.: Extreme storms impact on coastal sea-air CO2 fluxes: Black Sea shelf dynamics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15009, https://doi.org/10.5194/egusphere-egu26-15009, 2026.
Submesoscale features, characterized by intense horizontal and vertical exchanges, significantly influence the transport of heat, salt, and suspended matter, as well as upper-layer productivity. This study investigates submesoscale features at the coastal boundary on the Northwestern Black Sea shelf under the influence of Danube Delta waters. High-resolution simulations with an unstructured-grid model provide insight into the mechanisms governing submesoscale dynamics. We demonstrate that increased model resolution is crucial for accurately capturing submesoscale features, with particular attention to the vertical resolution required to represent the mixed-layer depth. Our results reveal that barotropic processes dominate the initial generation of submesoscale eddies, particularly in areas of abrupt coastline changes, such as Sacalin Island (Romania) and Cape Kaliakra (Bulgaria). In its turn, the baroclinic conversion is more significant in their subsequent growth and maintenance along the coast. The interaction between the Danube plume and submesoscale eddies is twofold. The Danube plume enhances the formation of eddies by creating shear and density gradients. On the other hand, the eddies facilitate the along-shore transport of brackish waters and contribute to restratification. These findings contribute to understanding the interplay between mixing and eddy processes, thus shedding more light on the dynamics of the coastal boundary layer.
How to cite: Gramcianinov, C., Stanev, E., Jacob, B., and Staneva, J.: On the genesis and development of coastal submesoscale eddies in the Northwestern Black Sea shelf, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9488, https://doi.org/10.5194/egusphere-egu26-9488, 2026.
The Mediterranean is one of the most nutrient-poor marine areas in the world, where the spatial and temporal changes in phytoplankton is difficult to capture due to the limited in-situ measurements, particularly across the Eastern Mediterranean. In this context, satellite-based remote sensing with increasing spatial resolution provides phytoplankton-related indicators, among which the most widely used is chlorophyll-a (Chl-a) for assessing phytoplankton biomass and eutrophication status of aquatic ecosystems. Chl-a levels in this region are shaped by both natural nutrient inputs, such as dust transport and wildfires, and anthropogenic influences, including terrestrial nutrient discharge. While the influence of episodic wildfire and dust transport on enhancing Chl-a has been investigated in this study, busy and increasing shipping activity of the region raised additional questions regarding its potential contribution to Chl-a levels, including an episode investigating the operations of livestock carriers. The livestock episode showed more local Chl-a enhancements around the shipping routes compared to wildfire and dust transport.
In this study, satellite-derived GCOM-C/SGLI Chl-a observations and high-resolution EMODnet shipping route density data were used for a five-year (2019-2023) spatio-temporal assessment across the Eastern Mediterranean, covering open-sea regions. The aim is to investigate the effect of maritime activity on phytoplankton dynamics through a route-based evaluation of shipping-intense areas first time in the literature.
Across the five-year period, Chl-a levels showed coastal-open sea contrast and strong seasonality in the region, while episodic investigations showed that wildfires and dust transport can trigger short-term but large-area increases. In the Eastern Mediterranean, open-sea areas with high shipping intensity showed systematically elevated Chl-a levels, and the novel grid-based percentile method developed showed that a significant correlation between high route density and increased Chl-a levels, particularly during the periods of limited phytoplankton growth. This relationship was statistically significant, with high-intensity shipping grids (≥75th percentile) showing higher Chl-a levels than low-intensity grids (≤25th percentile) across most months, especially from May to October. As the percentile levels increase from ≥75th to >99th percentile, Chl-a levels increased almost linearly. These findings proved that shipping activity play an important, and previously overlooked role in phytoplankton dynamics in the open-sea regions of the Eastern Mediterranean, further indicating the need to better quantify and manage contribution of shipping sector to algal growth.
Keywords: Chl-a; Eastern Mediterranean; Livestock Carrier; Shipping
How to cite: Saracoglu, S., Onay, M. G., Pehlivanoglu, E., and Kaynak, B.: Spatio-temporal changes of chlorophyll-a over the Eastern Mediterranean: A novel high-resolution methodology for investigating the possible impact of shipping sector, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-954, https://doi.org/10.5194/egusphere-egu26-954, 2026.
Chlorophyll and related pigments of phytoplankton modify seawater turbidity and light absorption, with consequences for the upper ocean heat uptake and dynamics. In this work, we investigate how different representations of light-chlorophyll feedback impact physical processes in the Mediterranean and Black Seas using a fully coupled ocean-biogeochemistry-atmosphere modelling system (NEMO-PISCES-WRF). We compare an interactive simulation, in which three-dimensional chlorophyll fields evolve dynamically within the PISCES model, with a non-interactive run forced with satellite-derived surface chlorophyll and assuming a uniform vertical profile, as commonly done in ocean circulation models. In both cases, chlorophyll concentration affects the ocean heat budget by modulating light absorption and local heating rates. Results show that explicitly representing vertical chlorophyll structure strongly modifies subsurface heating, particularly during stratified summer conditions. In productive regions such as the western Mediterranean and the Black Sea, high surface chlorophyll concentration creates a shading effect in both simulations, cooling subsurface waters that are later brought to the surface through winter mixing. Conversely, in the oligotrophic eastern Mediterranean, the presence of a Deep Chlorophyll Maximum enhances shortwave absorption below the mixed layer, resulting in warmer upper-ocean temperatures the following winter and an overall increase in ocean heat content. These results highlight the need to improve bio-optical representations in regional climate modelling of the Southern European seas, especially in low-productivity regions where chlorophyll maxima occur at depth and are not captured by satellite observations.
How to cite: Karagiorgos, J., Vervatis, V., and Sofianos, S.: Representing bio-optical interactions in a coupled modelling framework for the Southern European Seas, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8355, https://doi.org/10.5194/egusphere-egu26-8355, 2026.
We investigate the remote drivers and local impacts of the recent anomalous high salinity values observed in the Southern Adriatic by using a multi-platform data approach that combines in situ measurements, satellite products and model reanalysis. First, we quantify the relative importance of local atmospheric forcing and remote advective processes in shaping the decadal salinity evolution of the Eastern Mediterranean that in turn affects Adriatic. In fact, in the Levantine and Cretan basins, strong evaporation links a dramatic warming of the area, extreme marine–atmospheric heatwaves, and circulation changes in the Ionian Sea, drives the formation and persistence of anomalous saltier surface and intermediate waters in the area. Then these high salinity Levantine-origin waters flow into the Adriatic Sea through the Otranto strait contributing to the anomalous salinity values observed in the area and to enhance dense-water formation processes. Our results support the hypothesis that the recent Adriatic salinification is primarily controlled by basin-scale thermohaline circulation changes rather than pure local atmospheric forcing, with important implications for Eastern Mediterranean deep-water formation, biogeochemical cycles, and the sensitivity of the system to ongoing climate change.
How to cite: Mauri, E., Menna, M., Gacic, M., reale, M., Pirro, A., Gallo, A., Notarstefano, G., Poulain, P.-M., Bussani, A., Pacciaroni, M., Zuppelli, P., Saggese, C., and Martellucci, R.: Recent salinification in the Southern Adriatic: remote drivers and local impacts , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18495, https://doi.org/10.5194/egusphere-egu26-18495, 2026.
Coastal circulation is governed by closely linked interactions between atmospheric forcing, fresh water inflow, and complex bathymetry. Understanding these dynamics requires an integrated observational approach to adequately resolve surface transport processes. In this context, a multiplatform observational framework combining remote sensing, in situ measurements and numerical modelling was employed to study surface circulation in the Gulf of Trieste (GoT).
A preliminary observational analysis carried out in October–November 2023 addressed the interplay between surface circulation, wind forcing and river discharge, and, using high-frequency (HF) radar measurements, Weather Research and Forecasting (WRF) atmospheric simulations and river flow observations. The results show that easterly (Bora) wind events strengthen the GoT’s prevailing cyclonic circulation, enhancing surface outflow from the basin. In contrast, intense southerly winds induce a circulation reversal towards an anticyclonic regime, driving surface currents towards the coast. When strong river discharge episodes coincide with southerly wind conditions, a more complex scenario develops, characterised by anticyclonic flow in the central part of the GoT and cyclonic circulation in its northern sector.
To further assess near-surface dynamics and validate HF radar-derived currents under specific meteo-marine conditions, dedicated surface drifter experiments were carried out between late 2024 and 2025. Drifter trajectories showed strong agreement with HF radar observations, with high correlations between the observed velocity components and those derived from the radar. However, comparison with numerical model outputs revealed weaker consistency, highlighting the value of HF radar data for model validation and improvement via data assimilation methods.
Drifter pathways were closely associated with the low-salinity plume of the Isonzo River, confirming its pivotal role in driving near-surface transport. Additional coordinated deployments in 2025, allowed for a direct comparison between CODE and Stokes drifters, released from the same locations. The two kinds of drifters exhibited distinct responses, reflecting their different sampling depths. CODE drifters track currents at a depth of around 1 m, while Stokes drifters follow the immediate surface layer and are more sensitive to wind and wave forcing.
Overall, integrating HF radar observations, surface drifters and numerical simulations provides a robust framework for resolving variability in coastal surface circulation and improving the representation and operational forecasting of transport processes in numerical models of the GoT. This kind of approach can be easily exploited in other coastal areas with similar meteo-marine and bathymetric features.
How to cite: Lombardo, D., Menna, M., Martini, S., Pacciaroni, M., Giordano, F., Ingrassia, E., Bolzon, G., Bussani, A., Deponte, D., Querin, S., and Ursella, L.: A multiplatform analysis of wind- and river-driven surface circulation in the Gulf of Trieste (northern Adriatic Sea) using HF radar, drifters and numerical model data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20666, https://doi.org/10.5194/egusphere-egu26-20666, 2026.
The Black Sea is characterised by a persistent, strong stratification, which separates fresher surface water from more saline deep water. This stratification dampens vertical mixing and limits the ventilation of the deep water, thereby contributing to the oxygen deficiency underneath the pycnocline. However, plankton primary production regularly creates oxygen supersaturation at the pycnocline and thus improves the availability of oxygen in the pycnocline.
We have measured vertical profiles of salinity, temperature, and oxygen in the north-western shelf of the Black Sea in late summer. The spatial variance of water density enabled us to estimate the vertical turbulent diffusivity. The spatial variance of oxygen concentration enabled us to employ a 1D reaction- transport model to estimate pelagic rates of oxygen production and consumption, and vertical fluxes of oxygen across the pycnocline. These model-based estimates are complemented by direct measurements of pelagic respiration rates and primary production rates. The combined results enable us to quantify oxygen fluxes across the density gradient and to elucidate the significance of deep primary production for the ventilation of the deep water.
How to cite: Neumann, A., Slabakova, V., Balan, S., and Voynova, Y.: Diapycnal transport of oxygen in the north-western Black Sea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17082, https://doi.org/10.5194/egusphere-egu26-17082, 2026.
The Black Sea remains poorly studied regarding its carbonate system parameters and ocean acidification status. This is partly due to its characteristics as a semi-enclosed sea with significant riverine inflow and naturally high pH and total alkalinity (TA) levels, which generally suggest a stable buffering capacity. Such an assessment is necessary given the increasing anthropogenic pressures like climate change and increasing atmospheric CO2 and the rapid environmental changes observed in recent years.
With this study, we aim to contribute the understanding of the Black Sea carbonate system. The presented results are based on in-situ data spanning three consecutive years, with a sampling frequency of twice per month. Salinity was measured using a WTW TetraCon 925 (0.1 resolution), while total alkalinity (TA) was determined according to ISO 9963-1:1994 (high-precision open-cell potentiometric titration with an NIST-calibrated pH electrode). This objective is further driven by our use of autonomous observations and carbonate system sensors such as the continuously operating FerryBox system with a membrane-based pCO2 sensor at the IO-BAS Shkorpilovtsi research station
The observed relationships between salinity and alkalinity confirmed our hypothesis that the expected high correlation between these two parameters is absent in Black Sea coastal waters (r=0.08; r²=0.01). The correlation coefficient varies seasonally, and is highin summer (r=0.73; r²=0.53), but low in autumn (r=0.32; r²=0.16), when warm, nutrient- and biota-rich waters are characterized with maximum seasonal salinity (18.2 ‰),but lowest alkalinity (3.255 mmol/l). We also observed a low correlation during the spring and winter seasons. The spring salinity-alkalinity relationship is particularly interesting due to the sporadic influence of the Danube River on the North Bulgarian Black Sea coast, affecting salinity (average calculated minimum for the year of 16.2 ‰; absolute spring minimum of 13.8 ‰) and alkalinity (average calculated maximum for the year of 3.382 mmol/l). The winter patterns show similar trends but are driven by different factors: a decrease in salinity due to reduced evaporation of cold water and a slight recovery in alkalinity following the sharp autumnal decline.
These conclusions are discussed in the context of concurrently collected data on nutrients, both dissolved and suspended in the seawater and the comparison with FerryBox data on pH and pCO2.
How to cite: Drumeva, N., Doncheva, V., Voynova, Y. G., Macovei, V. A., and Slabakova, N.: Relationship between total alkalinity and salinity during different seasons in the coastal waters of the Northern Bulgarian Black Sea - an example from the IO-BAS Shkorpilovtsi monitoring station, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16833, https://doi.org/10.5194/egusphere-egu26-16833, 2026.
The well-dated and extensively studied Quaternary sedimentary record of the Mediterranean basin provides valuable insight into the dynamics of the basin. From this wealth of data, we try to achieve mechanistic understanding of the overturning circulation using conceptual box models. An outstanding aspect of the stratigraphic record are organic-rich deposits called sapropels. These deposits are excellent examples of sudden, strong responses to long-term climate variability. Sapropels are found (semi-)periodically for the last 13.5 million years, most prominently in the eastern basin. There is a strong correlation between the timing of the formation of sapropels and periods of North African monsoon intensification. This correlation strongly supports the hypothesis that increased freshwater input has resulted in prolonged periods of buoyancy gain and subsequent weakening or collapse of deep-water formation. The focus of this study is to explain the more intensely developed sapropel records in the eastern basin compared to the western basin. Specifically, we will address whether the geographical setting of the eastern basin alone can account for sapropel formation.
Where state-of-the-art Global Climate Models (GCMs) or high-resolution ocean models are able to capture the complex dynamics of the Mediterranean Sea, they are generally computationally demanding and are not suitable to perform long-duration (~100 kyr or longer) simulations. Consequently, either only snapshot studies are available or the spatial resolution is greatly reduced. Conceptual climate models or box models may offer us important new insights. With box models, we try to analyse the physical processes of the Mediterranean overturning circulation and related deep-water formation events. As such, we pay special attention to the forcings required for initiation and stagnation of the overturning circulation and deep water formation. A major benefit of using box models is that they are computationally efficient and that therefore they allow us to test and simulate a large range of configurations and parameter combinations. In addition, we are able to study the transient response to changes in the climate instead of only snapshots. In an important step forward from previous modelling studies, we make a distinction between the western- and eastern basin.
How to cite: Keulers-Evelo, S. and Meijer, P.: Exploring the mechanism of Mediterranean overturning circulation using the sedimentary record and conceptual box models , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11086, https://doi.org/10.5194/egusphere-egu26-11086, 2026.
The Adriatic Observatory Network has revealed new aspects of dense water spreading in the Eastern Mediterranean Sea. By integrating multiple observing infrastructures and producing FAIR (Findable, Accessible, Interoperable, Reusable) data, the network has uncovered previously unexplored features, highlighting their influence on thermohaline circulation and biogeochemical fluxes in the Mediterranean Sea, a key hotspot of climate change and biodiversity. In 2016-2017, the central Mediterranean experienced significant heat loss, reduced freshwater input, and a cyclonic phase of the Northern Ionian Gyre, which drove salty water into the Adriatic. These conditions facilitated dense water formation in the northern and southern Adriatic by shelf and open-ocean convection. The dense water formed in the north, flows southward along the western continental slope, in part cascading into the southern Adriatic Pit, where it mixes with resident waters to form the Adriatic deep water, which then spreads into the Ionian Sea. Our findings revealed that the dense water exiting the Adriatic follows two distinct pathways in the Ionian: a westward branch toward the Gulf of Taranto, which contributed to the reversal of the Northern Ionian Gyre, and a southward branch toward the Kerkyra–Kefalonia Valley, spreading directly into the deep Hellenic Trench, ventilating its deep layers due to its high density and thus playing a key role in the renewal of the basin.
How to cite: Paladini de Mendoza, F., Menna, M., Cardin, V., Riminucci, F., Langone, L., Cantoni, C., Bergami, C., Grilli, F., Bastianini, M., Miserocchi, S., Gallo, A., Giordano, P., Toller, S., Reale, M., Marini, M., Le Meur, J., Poulain, P. M., Mauri, E., Gacic, M., and Martellucci, R.: Dual pathways of Adriatic Deep Water export and their role in Ionian gyre reversal and deep ventilation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16729, https://doi.org/10.5194/egusphere-egu26-16729, 2026.
Understanding the anthropogenic influence on the ocean is essential for quantifying the human-induced changes in the state of the ocean. The Levantine basin is a key semi-enclosed sub-basin of the Eastern Mediterranean that underwent significant human induced modifications following the construction and operation of Aswan High Dam (AHD) on the Nile River which became operational in 1964. Large river systems play a crucial role in modulating thermohaline properties in the semi-enclosed basins, and river regulation can alter key physical processes including circulation, eddy activity, stratification, and basin-scale salinity budgets.
Here we investigate the oceanic response to the post-AHD reduction in Nile freshwater discharge using a 1/16° mesoscale-resolving configuration of the Mediterranean Sea implemented, with open boundary conditions in the Atlantic Ocean. Simulations are performed using the NEMO v5 modelling framework, forced with ECMWF ERA5 atmospheric fields. The model is initialized in January 1958 and constrained at the open boundaries with monthly fields from the ECMWF ORAS5 ocean reanalysis. Sensitivity tests have been conducted in order to avoid the stochastic behavior of the numerical models and to distinguish between the signal from the numerical noise. Our results provide new insight into the physical impacts of Nile river damming on the Mediterranean thermohaline structure and circulation, contributing to a more quantitative understanding of human-induced modifications in semi-enclosed marine basins.
How to cite: Saad, M., Trotta, F., Coppini, G., and Pinardi, N.: Modeling the Impacts of Aswan High Dam Driven Nile Discharge Reduction on the Mediterranean Sea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13279, https://doi.org/10.5194/egusphere-egu26-13279, 2026.
Posters virtual: Tue, 5 May, 14:00–18:00 | vPoster spot 1a
EGU26-5203 | Posters virtual | VPS20
The role of the air-sea water fluxes and the lateral influence on salinity in the bimodal circulation variability of the Northern Ionian Gyre in the period 1988-2020Tue, 05 May, 14:42–14:45 (CEST) vPoster spot 1a
The variability in the circulation of the Northern Ionian Gyre (NIG) during 1988-2020 is assessed via dynamic-height fields in the upper layer (0-120 m and 0-398 m) derived from the monthly-averaged temperature and salinity fields of the Copernicus reanalysis data. The yearly-averaged dynamic-height fields agree with the corresponding fields of altimetric sea-surface topography used in previous studies that found, at the area of the NIG, a maximum-variability mode in the sea-surface topography of the Ionian Sea. In the present results, the NIG coincides with the area of a) the variability maxima of the dynamic-heights, existing on the standard-deviation (std) maps of the yearly-averaged dynamic heights during 1988-2020, b) the std maxima of the averaged density in the upper layer and c) the std maxima of the averaged salinity in the upper layer; the density-salinity correlation coefficients in the upper-layer within the NIG range from 0.87 to 0.74.
Moreover, the std maxima of the precipitation fluxes, which have the dominant role on the evaporation-minus-precipitation (E-P) budget, are also located on the NIG area. The 5-year running-averaged values of yearly E-P and salinity in the upper-layer of the NIG, which filter out the variability in less that ~5-6 years while they preserve the dominant variability in the periodicities (~8-10 years) of the NIG-circulation, have statistically significant correlations ranging from 0.53 for the period 1990-2018 to 0.73 for the period 1997-2018. After ~2005, the two timeseries resemble to each other even more. In the upper layer, the area to the east-southeast of the NIG has statistically significant correlations in salinity (correlation coefficients: ~0.68-0.8) with the NIG area. This area can feed its higher-salinity signal to the NIG via northward transfer during the cyclonic circulation mode of the NIG.
How to cite: Kontoyiannis, H., Tsiaras, K., Iona, A., and Ballas, D.: The role of the air-sea water fluxes and the lateral influence on salinity in the bimodal circulation variability of the Northern Ionian Gyre in the period 1988-2020, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5203, https://doi.org/10.5194/egusphere-egu26-5203, 2026.
