engleski

CLIMATE INDUCED VARIATIONS OF PHYSICAL AND CHEMICAL STRUCTURE OF THE ADRIATIC SEA

Multidecadal pattern of physical and chemical parameters in the Adriatic sea is mostly controlled by the climate factors throught combined effect of the heat exchange, precipitation, river runoff and water exchange across the Otranto Strait. In this paper we investigated Northern Hemisphere climate effects on the long term variability of the thermohaline structure in the Adriatic Sea during the period 1961-2008 from seasonal to interannual scale. Although the linkage between ocean temperature and salinity changes and atmospheric climatic trends exist on decadal to long-term scales, the results obtained for various basins (for example Bering Sea, Baltic and North Sea) suggest that shifts in the climate regime can be responsible for shifts in the marine hydrochemical parameters. Recent investigation in the Adriatic Sea suggest that observed shift in the thermohaline and chemical structure was controlled with northern hemispheric climate variation. While the years 1980-1986 showed an increasing trend, the years 1987-1996 where characterized by an inverse pattern of temperature, salinity and oxygen concentration. Such opposite patterns appeared linked to modifications in thermohaline circulation related to the Eastern Mediterranean Transient (EMT) whose effects prevented warm and saltier water masses intrusions into the Adriatic and reduced local temperature and salinity. Weak ventilation in the Adriatic was therefore evidenced in the lower than normal sea temperature, salinity and oxygen concentrations below the thermocline. These results indicate to connections between shifts in middle Adriatic with Northern Hemisphere climate system via changes in regional atmospheric conditions, and highlight the role of atmospheric variability may play as a triggering factor for marine ecosystem changes.

Thermohaline structure; teleconnections; interannual variability

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