Observed basin‐wide propagation of Mediterranean water in the Black Sea

Abstract

Mediterranean water entering the Black Sea through the Bosphorus Strait forms middepth intrusions that contribute to the salt, heat, and volume balances of the sea, ventilate its water column at intermediate depths and restrain the upward flux of hydrogen sulfide from deeper layers. Despite the importance for the Black Sea environment, the circulation of Mediterranean‐origin water in the basin is fundamentally underexplored. Here we use hydrographic data collected from ships and Argo profiling floats to identify pathways of the Mediterranean intrusions in the general circulation system of the sea. While earlier the intrusions were observed primarily near the Bosphorus Strait, we present an evidence for their intermittent extensive propagation throughout the basin. We find that the main conduit for the intrusions is the southern limb of the Rim Current that carries the intruded water from the Bosphorus Strait eastward. A part of this eastward flow recirculates cyclonically into the interior of the sea, where traces of the intrusions gradually disappear because of mixing. We put forward the hypothesis that the formation of the most prominent intrusions is associated with strong cyclonic storms over the Bosphorus Strait, which lead to abnormally large influx of Mediterranean water.

Black Sea dissolved organic matter dynamics: Insights from optical analyses

“…a), and layer distinctions as well as the number of samples collected are summarized in Table . The upper anoxic layer (UAOL)‐deep anoxic layer (DAOL) boundary described by Margolin et al () was based on previously identified θ anomalies, which have more recently been observed at depths approximately between 400 m and 600 m, near σ θ = 17 kg m −3 (Falina et al ). The distributions of temperature, θ , S P , σ θ , and the concentrations of oxygen, nitrate, H 2 S, and DOC, along with layer boundary calculations, are reported by Margolin et al () and many are included in Fig.…”

Water Exchange through Canal İstanbul and Bosphorus Strait

“…An equally important effect is the predicted increase in the lower-layer flux of the Bosphorus, which is all too important in terms of the interior mixing processes of the Black Sea (Özsoy et al, 1993;Delfanti et al, 2014;Falina et al, 2007Falina et al, , 2017. One of the adverse influences in the long-term would be the potential to change the stratification in the Black Sea, with increased injection of the nutrient rich lower-layer waters of the Marmara Sea contributing to the long-term decline of the Black Sea basin.…”

“…The increase in the upper-layer flux is threatening for the Marmara Sea ecosystem, with further downs tream effects possibly transmitted to the Aegean Sea, especially in the North Aegean Sea whose stratification and dense water formation properties are sensitive to the Black Sea Water (BSW) transported via buoyant surface currents of the Dardanelles Strait (Zervakis et al, 2000). Similarly, the increased lower-layer flow entering the Black Sea has potential to influence the sensitive Black Sea stratification and mixing processes (Özsoy et al 1993(Özsoy et al , Delfanti et al, 2014Falina et al, 2007Falina et al, , 2017. Both types of influences may have significant consequences on climate time-scales.…”

Circulation of the Turkish Straits System between 2008–2013 under complete atmospheric forcings

“…12b over the Black Sea shelf and propagate over large distances across the interior of the Sea at intermediate depths (Falina et al, 2017). The model results in Fig.…”