Caesium-137 activity concentrations (137Cs) were measured between 2003 and 2014 in the water column of Lemnos and Cretan deep basins of the Aegean Sea. The purpose was to assess water-mass dynamics and mixing processes by combining typical oceanographic data with the activity concentrations of 137Cs. The radiological data, combined with dissolved oxygen profiles, provided substantially more information than solely temperature and salinity regarding processes such as water-mass identification, formation and mixing. In each basin it was possible to determine stagnant periods, where turbulent mixing was dominant, as well as periods where replenishment of the deep basins had been taken place. At Lemnos basin, the data profile in 2013 proved evidence of water column ventilation down to 800 m and replenishment of the deep basin by less saline water mass. The 137Cs information provided evidence for contribution of water from the Black Sea to the intermediate and deep layers of the South Aegean (Cretan) basin. The profiles of 2013 and 2014 were characterized by the return of 137Cs inventories to pre-Chernobyl levels.
Vertical distribution and temporal trends of 137Cs at Lemnos and Cretan deep basins of the Aegean Sea, Greece
Delfanti R.;
2020-01-01
Abstract
Caesium-137 activity concentrations (137Cs) were measured between 2003 and 2014 in the water column of Lemnos and Cretan deep basins of the Aegean Sea. The purpose was to assess water-mass dynamics and mixing processes by combining typical oceanographic data with the activity concentrations of 137Cs. The radiological data, combined with dissolved oxygen profiles, provided substantially more information than solely temperature and salinity regarding processes such as water-mass identification, formation and mixing. In each basin it was possible to determine stagnant periods, where turbulent mixing was dominant, as well as periods where replenishment of the deep basins had been taken place. At Lemnos basin, the data profile in 2013 proved evidence of water column ventilation down to 800 m and replenishment of the deep basin by less saline water mass. The 137Cs information provided evidence for contribution of water from the Black Sea to the intermediate and deep layers of the South Aegean (Cretan) basin. The profiles of 2013 and 2014 were characterized by the return of 137Cs inventories to pre-Chernobyl levels.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
