The Mediterranean Sea: a miniature ocean for climatic and environmental studies and a key for the climatic functioning of the North Atlantic
Résumé
The Mediterranean Sea provides a case study not only for dense water formation and climatic functioning at a basin scale, but also as a body of water evolving in response to the effects of environmental changes, Through marine circulation, marine signatures of changes may be used to provide estimates of the evolution of the external driving forces of climate and environment. That is to say, to provide a coupling between marine sciences and climatic and socio-economic studies. Different examples may be given: i) nutrients and trace metal changes in the western Mediterranean permit quantification of external changes at a basin scale; ii) sapropels (organic-rich layers sedimented in anoxic conditions) provide records for the last 2 million years of interactions between marine circulation, climate and biology; iii) temperature and salinity changes that have taken place since the 1960s in response to changes in hear and water budgets across the sea surface. Sapropel studies and ongoing changes in temperature and salinity also require that the Mediterranean functioning be considered in relation to global climate and to the Atlantic Ocean, as well as taking into account the changing role of salty Mediterranean waters in the Atlantic Ocean, These factors highlight a dual role for the Mediterranean Sea, which acts as a miniature ocean for physical, chemical or climatic and environmental studies, and also as a key factor in understanding global ocean circulation in which past changes have taken place, (C) 1999 Elsevier Science Ltd. All rights reserved.