| Abstract |
Sapropels, i. e. discrete, black and organic-rich layers sedimented in the Eastern basin in anoxic conditions, constitute record, over the past 500,000 years, of eleven particular interactions between marine circulation and biology during glacial as well as temperate climates. Considering climatic and dynamic aspects, we argue that this formation is preconditioned by the stoppage of dense water formation in the Adriatic Sea, following sea-level and/or freshwater input changes. In this case, oxygenation of eastern deep water depends solely on the dense water formation in the South Aegean Sea, a process modified by episodic freshwater inputs. This scheme explains correlations between sapropel events and the strong African monsoons responsible for Nile river flooding over several thousand years (Rossignol-Strick, 1983). At the time of sapropel formation, Mediterranean general dynamics and planktonic productivity were not drastically changed. The deciphering of Mediterranean climatic records needs to take into account northern ice sheet changes (via sea-level, temperature and salinity in the adjacent Atlantic), as well as tropical climatic oscillations (via increased freshwater inputs and sapropel events). |
