North Adriatic Dense Water: lessons learned since the pioneering work of Mira Zore-Armanda 60 years ago

Abstract

This review first pays tribute to the famous Croatian oceanographer, Mira Zore-Armanda, and her seminal work on the Adriatic water masses in 1963, and emphasises the importance of the densest Mediterranean water mass: North Adriatic Dense Water (NAddW). This water mass is generated through substantial wintertime surface cooling and evaporation over the wide northern Adriatic and is known to (1) influence the Adriatic-Ionian thermohaline circulation, (2) bring oxygen and carbon to the deep Adriatic layers and, (3) more generally, have a substantial impact on the physics and biogeochemistry of the whole Adriatic. Second, the NAddW physics, from preconditioning, through generation and spreading, to accumulation in Adriatic depressions, is reviewed. Then, the temporal evolution of the NAddW properties influenced and connected to (1) basin-wide interannual and decadal variability and (2) trends towards warmer and saltier source characteristic due to ongoing climate change, is discussed. The importance of long-term observations and atmosphere-ocean modelling in event, decadal and climate studies is then presented. Finally, a review of the identified gaps and perspectives for future research is concluding this article.

The Role of Nitrogen and Phosphorus in Eutrophication of the Northern Adriatic Sea: History and Future Scenarios

“…These colder and less saline waters flow close to the Italian coast throughout the water column. In contrast, during the summer season, the hydrodynamic conditions change, resulting in weaker currents and a series of clockwise and anticlockwise gyres, as well as strong water column stratification, with colder waters from the previous winter near the bottom [12,[24][25][26][27][28][29]. As a result, nutrient concentrations in the surface waters increase, creating favorable conditions for the growth of phytoplankton and macroalgae.…”

Evolution of Freshwater Runoff in the Western Adriatic Sea over the Last Century

“…Due to the predominant cyclonic circulation of the Adriatic Sea, the Po River and other alpine rivers located in the northernmost part of the basin discharge nutrients into its waters along the western side. These rivers are responsible for significant eutrophication processes that have been periodically observed along the Italian coasts [20][21][22][23][24], at least since the 1960s, causing hypoxia phenomena and dinoflagellate blooms [25,26]. Since the 1950s, the ever-increasing use of fertilizers, prompted by intensive farming along the Po River basin, has had a significant impact on the inflow of nitrogen (N) and phosphorus (P) into the Northern Adriatic Sea [27,28].…”

Kilometre-Scale Assessment of the Adriatic Dense Water Multi-Decadal Dynamics

“…One of the main processes driving the Adriatic thermohaline circulation is the formation of North Adriatic Dense Water (NAddW; Zore-Armanda, 1963) that occurs, in winter, over the northern Adriatic shelf and the Kvarner Bay during extreme bora eventsi.e., downslope winds strongly influenced by the complex northeastern Adriatic coastal orography and associated with hurricane-strength gusts up to 50 m s -1 (Belušić and Klaić, 2004). In the last 40 years, the Adriatic dense water dynamics has mostly been derived from observations (Artegiani and Salusti, 1987;Gačić et al, 2002;Vilibić and Mihanović, 2013;Querin et al, 2016;Foglini et al, 2016;Paladini de Mendoza et al, 2022) and has been summarized in the review study of Vilibić et al (2023) as follows. First, the NAddW formation is known to be preconditioned by three main factors: the bora-induced surface heat losses, the northern Adriatic river fresh water influxes, and the advection of more saline water masses from the Ionian Sea.…”