The Mediterranean Sea: a miniature ocean for climatic and environmental studies and a key for the climatic functioning of the North Atlantic

The Mediterranean Sea provides a case study not only for dense water format ion and climatic functioning at a basin scale, but also as a body of water evolving in response to the effects of environmental changes, Through marin e circulation, marine signatures of changes may be used to provide estimate s of the evolution of the external driving forces of climate and environmen t. That is to say, to provide a coupling between marine sciences and climat ic and socio-economic studies. Different examples may be given: i) nutrient s and trace metal changes in the western Mediterranean permit quantificatio n of external changes at a basin scale; ii) sapropels (organic-rich layers sedimented in anoxic conditions) provide records for the last 2 million yea rs of interactions between marine circulation, climate and biology; iii) te mperature and salinity changes that have taken place since the 1960s in res ponse 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 a nd to the Atlantic Ocean, as well as taking into account the changing role of salty Mediterranean waters in the Atlantic Ocean, These factors highligh t a dual role for the Mediterranean Sea, which acts as a miniature ocean fo r physical, chemical or climatic and environmental studies, and also as a k ey factor in understanding global ocean circulation in which past changes h ave taken place, (C) 1999 Elsevier Science Ltd. All rights reserved.