Deep water formation in the Eastern Mediterranean - Cruise No. MSM15/4 - July 07-July 17, 2010 - Marsaxlokk (Malta)-La Valetta (Malta)

Freier Zugriff
in MARIA S. MERIAN-Berichte; MSM15/4; 1-21; MARIA S. MERIAN-Berichte

Dokumentinformationen

  • Format / Umfang:
    21 pages
  • ISSN:
  • DOI:
  • Medientyp:
    Aufsatz (Zeitschrift)
  • Format:
    Elektronische Ressource
  • Sprache:
    Englisch
  • Klassifikation:
    DDC:    550 Earth sciences and geology

Abstract

Since the late 1980s the Eastern Mediterranean Sea (EM) underwent major climate shifts, the first one known as the Eastern Mediterranean Transient (EMT) during which waters of Aegean origin replaced Adriatic Deep Water (AdDW) in the bottom layers of the Ionian Sea. A further major shift occurred between 1999 and 2003 where AdDW came back as a major source of bottom water in the Ionian basin. At the latest since then it is broadly accepted that the relationship between water masses of the Ionian, Aegean and Adriatic Sea is very complex, especially because the density of the abyssal water masses are laying very closely together and the source water masses of the Adriatic and Aegean Sea interact with each other influencing their composition and causing nowadays large variability for water mass formation and stratification in the EM. Several cruises (such as POSEIDON 298, METEOR M71-3, MERIAN MSM13-2) have been accomplished to help understanding the processes involved. MERIAN cruise 15-4 is one of the last in this series. A hydrographic survey with CTD and XBT measurements was carried out in the Adriatic and Ionian Sea to determine water masses and their mixing rates. These investigations were additionally supported by microbiological measurements with the help of which the composition and the activity of microorganisms of different water masses are analysed, in order to ascertain the origin of the Ionian Deep Water (EMDW). Moorings which were deployed during MERIAN cruise 13-2 in October 2009 were recovered on the cruise. They should deliver insight into possible transport routes of AdDW into the Ionian Sea. Furthermore, measurements with a shipborne ADCP allow for additional information about the upper ocean circulation in the EM.


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