The Deep Adriatic Transient

The deep Southern Adriatic Pit (dSAP) is a Mediterranean region highly sensitive to climate change, influenced by dense water cascading from the northern Adriatic and heat/salt transport from the Eastern Mediterranean. Historical (since 1957) and modern (permanent and opportunistic CTD sampling, Argo floats, fixed moorings) measurements reveal a mid-2000s transition in dSAP thermohaline properties. Previously marked by steady increases in temperature, salinity, and density, with substantial saw-tooth decadal variability, the dSAP has experienced unprecedented warming (0.8°C) and salinization (0.2) over the past decade, accelerating in time and reversing density trends. The inflow of much more saline waters reduced SAP stratification and altered dense water properties at its source in the northern Adriatic. This at least fivefold acceleration of the high-emission regional climate projections may have substantial effects on the Adriatic biogeochemistry and living organisms, increasing sea level rise trends and more.