Holocene Aridity-Induced Interruptions of Human Activity along a Fluvial Channel in Egypt’s Northern Delta

Geoarchaeological information presented here pertains to a subsidiary Nile channel that once flowed west of the main Sebennitic distributary and discharged its water and sediments at Egypt’s then north-central deltaic coast. Periodical paleoclimatic episodes during the later Middle and Upper Holocene included decreased rainfall and increased aridity that reduced the Nile’s flow levels and thus likely disrupted nautical transport and anthropogenic activity along this channel. Such changes in this deltaic sector, positioned adjacent to the Levantine Basin in the Eastern Mediterranean, can be attributed to climatic shifts triggered as far as the North Atlantic to the west, and African highland source areas of the Egyptian Nile to the south. Of special interest in a study core recovered along the channel are several sediment sequences without anthropogenic material that are interbedded between strata comprising numerous potsherds. The former are interpreted here as markers of increased regional aridity and reduced Nile flow which could have periodically disrupted the regional distribution of goods and nautical activities. Such times occurred ~5000 years B.P., ~4200–4000 years B.P., ~3200–2800 years B.P., ~2300–2200 years B.P., and more recently. Periods comparable to these are also identified by altered proportions of pollen, isotopic and compositional components in different radiocarbon-dated Holocene cores recovered elsewhere in the Nile delta, the Levantine region to the east and north of Egypt, and in the Faiyum depression south of the delta.

Lagrangian eddy tracking reveals the Eratosthenes anticyclonic attractor in the eastern Levantine Basin

Statistics of anticyclonic eddy activity and eddy trajectories in the Levantine Basin over the 2000–2018 period are analyzed using the DYNED-Atlas database, which links automated mesoscale eddy detection by the Angular Momentum Eddy Detection and Tracking Algorithm (AMEDA) algorithm to in situ oceanographic observations. This easternmost region of the Mediterranean Sea, delimited by the Levantine coast and Cyprus, has a complex eddying activity, which has not yet been fully characterized. In this paper, we use Lagrangian tracking to investigate the eddy fluxes and interactions between different subregions in this area. The anticyclonic structure above the Eratosthenes Seamount is identified as hosting an anticyclone attractor, constituted by a succession of long-lived anticyclones. It has a larger radius and is more persistent (staying in the same position for up to 4 years with successive merging events) than other eddies in this region. Quantification of anticyclone flux shows that anticyclones that drift towards the Eratosthenes Seamount are mainly formed along the Israeli coast or in a neighboring area west of the seamount. The southeastern Levantine area is isolated, with no anticyclone transfers to or from the western part of the basin, defining the effective attraction basin for the Eratosthenes anticyclone attractor. Co-localized in situ profiles inside eddies provide quantitative information on their subsurface physical anomaly signature, whose intensity can vary greatly with respect to the dynamical surface signature intensity. Despite interannual variability, the so-called Eratosthenes anticyclone attractor stores a larger amount of heat and salt than neighboring anticyclones, in a deeper subsurface anomaly that usually extends down to 500 m. This suggests that this attractor could concentrate heat and salt from this subbasin, which will impact the properties of intermediate water masses created there.

Sightings and stranding reports of Fin whales (Balaenoptera physalus) in the Levantine Sea, with recent sightings from Turkey

Fin whales (Balaenoptera physalus) are the most commonly observed mysticetes within the Mediterranean Sea, however their status remains vulnerable (VU) and their population in decline mainly due to increasing anthropogenic activities. Sightings of fin whales in the eastern Mediterranean are negligible relative to the central and western basins which eludes to the impression that the eastern Mediterranean provides a less favourable habitat for these cetaceans. This study outlines the sighting and stranding reports of fin whales in the Levantine Basin, the latest of which (an opportunistic sighting of four sub-adults off the coast of Anamur, Turkey in March, 2019) demonstrates the continued presence of this species in the eastern Mediterranean. The current report highlights the need for increased targeted survey effort and collaborative research between neighboring waters to enhance our understanding of the population status of this vulnerable species and aid in the implementation of the necessary conservation actions that are long-missing.

Seasonal and Interannual Variability of the CO2 System in the Eastern Mediterranean Sea: A Case Study in the North Western Levantine Basin

The seasonal variability of the carbonate system in the eastern Mediterranean Sea (EMed) was investigated based on discrete total alkalinity (AT), total dissolved inorganic carbon (CT), and pH measurements collected during three cruises around Crete between June 2018 and March 2019. This study presents a detailed description of this new carbonate chemistry dataset in the eastern Mediterranean Sea. We show that the North Western Levantine Basin (NWLB) is unique in terms of range of AT variation vs. CT variation in the upper water column over an annual cycle. The reasons for this singularity of the NWLB can be explained by the interplay between strong evaporation and the concomitant consumption of CT by autotrophic processes. The high range of AT variations, combined to temperature changes, has a strong impact on the variability of the seawater pCO2 (pCO2SW). Based on Argo float data, an entire annual cycle for pCO2SW in the NWLB has been reconstructed in order to estimate the temporal sequence of the potential “source” and “sink” of atmospheric CO2. By combining this dataset with previous observations in the NWLB, this study shows a significant ocean acidification and a decrease in the oceanic surface pHT25 of −0.0024 ± 0.0004 pHT25 units.a–1. The changes in the carbonate system are driven by the increase of atmospheric CO2 but also by unexplained temporal changes in the surface AT content. If we consider that the EMed will, in the future, encounter longer, more intense and warmer summer seasons, this study proposes some perspectives on the carbonate system functioning of the “future” EMed.

Late Mesozoic – Cenozoic evolution of the eastern Cyprus offshore

<p>The present‐day tectonic setting of the Eastern Mediterranean Sea results from a long deformation history, characterized by an alternation of extensional and contractional phases: from Mesozoic rifting to Late Cretaceous-present-day compression. This study focused on the tectonic reconstruction of the north-eastern side of the Mediterranean Sea, on a sector located between the Turkish coast and the northern Levantine Basin, using seismic reflection profiles. Previous studies dealt with the recent (Neogene) evolution because they did not have enough depth of investigation to recognize deeper reflections. We used vintage data such as MS and Strakhov surveys to analyze the deeper part of the area. We interpreted and depth-converted these seismic data, and we developed a sequential restoration to reconstruct the stratigraphic and structural evolution of the study area. </p><p>In general, from north to south, we recognize the Cilicia Basin: a piggy-back basin bordered to the south by the offshore continuation of the Kyrenia Range. The Kyrenia Range is a positive flower structure generated during a transpressional phase because of the rotation of the Arabic plate. Southward, a secondary contractional system with an onlapping wedge is present in the area between the Kyrenia Range and another prominent ridge, i.e. the Larnaca Ridge. In the southern part, the same transpressional phase that generated the Kyrenia Range led to a positive inversion of an ancient extensional system, i.e. the Latakia Ridge. Beyond these positive flowers, the Levantine Basin is affected by extensional structures showing weak positive reactivation, including halokinetic features.</p><p>In summary, we found that the inherited extensional structures strongly impacted the following contractional ones affecting both their geometry and their kinematics.</p>

Variability of the hydrological characteristics of the Eastern Mediterranean over the last decade

<p><span>A hydrodynamic simulation is carried out over the entire Mediterranean basin at a resolution of 3 to 4 km and a duration of about 10 years (2011-2020). The results are systematically evaluated using Argo profiles focusing on the spatial distribution of water mass properties along their path, the main mesoscale structures, the mean vertical temperature and salinity profiles by sub-basins as well as their "pseudo temporal evolution" biased by the variability of the spatial and temporal distribution of Argo observations.</span></p><p><span>The simulation has generally very low mean biases (of the order of 0.01 for salinity) and correlations on the monthly time series reconstructed from the observations, of the order of 0.9 at the scale of the eastern basin, both in surface waters and at 200 m in intermediate waters. </span></p><p><span>The evolution of salinity over the decade is then analyzed from the simulation. Particular attention is paid to the main basins of water mass formation, the Adriatic, the Levantine basin and the South Aegean Sea. The factors driving this evolution are analyzed in each of these basins. The propagation of the changes from these formation areas to the entire eastern basin is then examined, with a particular focus on the intermediate waters. </span></p>

Lagrangian eddy tracking reveals the Eratosthenes anticyclonicattractor in the eastern Levantine basin

<p>Statistics of anticyclone activity and trajectories in the southeastern Mediterranean sea over the period 2000-2018<br>is created using the DYNED atlas, which links the automated mesoscale eddy detection by the AMEDA algorithm with in<br>situ oceanographic observations. This easternmost region of the Mediterranean sea, delimited by the Levantine coast and<br>Cyprus, has a complex eddying activity, which has not yet been fully characterized. Using Lagrangian tracking<br>to investigate the eddy fluxes and interactions between different subregions in this area, we find that the southeastern Levantine<br>area is isolated, with no anticyclone exchanges with the western part of the basin. Moreover the anticyclonic structure above<br>the Eratosthenes seamount is identified as being an anticyclone attractor, differentiated from other anticyclones and staying<br>around this preferred position up to four years with successive mergings. Colocalized in situ profiles inside eddies provide<br>quantitative information on their subsurface structure and show that similar surface signatures correspond to very different<br>physical properties. Despite interannual variability, the so-called "Eratosthenes attractor" stores a larger amount of heat and<br>salt than neighboring anticyclones, in a deeper subsurface anomaly that usually extend down to 500 m. This suggests that this<br>attractor could concentrate heat and salt from this sub-basin, which will impact the properties of intermediate water masses<br>created there.</p>

The new CYCOFOS forecasting at coastal, sub-regional and regional scales in the Mediterranean and the Black Sea

<p>The Cyprus coastal ocean forecasting system, known as CYCOFOS has been providing operational hydrodynamical and sea state forecasts in the Eastern Mediterranean since early 2002. Recently, it has been improved with the implementation of new hydrodynamic and new wave modeling systems with the objective of targeting higher resolution domains, at coastal, sub-regional and regional scales in the Mediterranean and the Black Sea. For the new CYCOFOS hydrodynamic modeling system a novel parallel version of the well established POM has been implemented. The new CYCOFOS hydrodynamical models covers the entire Eastern Mediterranean with a resolution of 2 km and the Levantine Basin with a resolution of ~600 m, both nested in the Copernicus Marine Environmental Monitoring Service of the Mediterranean Forecasting Center-CMEMS Med MFC. For sea waves forecasting, CYCOFOS has implemented  the new ECMWF wave model WAM CY46R1 in the Mediterranean and the Black seas at a higher resolution of 5 km. The CYCOFOS hydrodynamical models received an extended cal/val against the parent model, Argo profiles and satellite SST time series, while in-situ wave data gathered by the HERMES buoy monitoring network in the Eastern Mediterranean and the Black Sea were used for statistical validation of the new CYCOFOS wave forecasts. The new CYCOFOS validated modeling systems,  provide higher resolution quality controlled forecasting data suiting the needs for : a) down-streaming applications supporting risk assessment for offshore platforms in the Levantine Basin and studies concerning the coastal erosion in the Eastern Mediterranean (Albania, Cyprus, Greece) and the Black Sea (Bulgaria) in the framework of the HERMES project, and b) further hierarchical downscaling applications for the development of the COASTAL CRETE operation forecasting system at a higher resolution in the Eastern Mediterranean (Crete, Greece).</p>