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2. MARUM-Workshop:
The meridional circulation of the Atlantic Ocean (MOC) is an important climatic element because it is accompanied by a net northward transport of sensible heat in the ocean. Furthermore, it is intimately coupled to the transport of latent heat in the atmosphere and thus to the hydrological cycle. Finally, it also affects the dynamic sea-level height. The possibility that this overturning circulation can change in the future (IPCC, 2007) is the main motivation to understand how it may have differed in the past. The Last Glacial Maximum (LGM) was a period during which the factors controlling the structure of the Atlantic MOC (e.g., freshwater budgets and atmospheric circulation in the northern and southern high latitudes) appear to have differed from today. In the 1980s, a prominent community effort provided evidence suggesting that this Atlantic overturning circulation may not have existed in its current form during the LGM. The nutrient poor NADW seemed to have been replaced by higher-nutrient waters like those formed in the Southern Ocean today. Both theoretical studies and ocean general circulation model experiments suggested that the MOC may have multiple equilibria and that transitions between the equilibria may be triggered by anomalies in the freshwater fluxes at the sea surface. State-of the-art coupled ocean-atmosphere general circulation models produce widely different Atlantic circulation scenarios when forced with LGM atmospheric CO2 concentration and ice sheet configuration. Some show a stronger overturning cell associated with NADW formation either extending slightly deeper or unchanged in vertical extent; others show a weaker and shallower overturning cell associated with NADW production. Since the 1980s Ph/Th and Nd isotopes have been established as new proxies. Furthermore, quality and quantity of the available data and the associated stratigraphies have been considerably improved. For this reason, we see the chance that a new synthesis of the available data will provide us with new insights on the mode of deep ocean circulation during the last glacial maximum.
This 3-day workshop will bring together leading international scientists in paleoceanography. The main goal of the workshop is to compile a global data base of proxies related to deep water circulation and that have the potential to be simulated in climate models. These include d18O, d13C, Cd/Ca, Mg/Ca and 14C of benthic foraminifera as well as Pa/Th, Nd and sortable silt. Further important questions to be addressed include:
- What is the state of the art distribution of deep water properties during the LGM based on established water mass proxies (d13C, d18O, Cd/Ca)?
- Do kinematic proxies (Pa/Th, Nd, 14C, grain size) support the general view of a shallower and somewhat weaker overturning during the LGM?
- Which models show the best representation of the ice-age circulation state?
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Confirmed participants (updated 16.11.08):
Jean Lynch-Stieglitz (GeorgiaTech), Torsten Bickert (MARUM), Luke Skinner (University of Cambridge), Elisabeth Michel (LSCE, Gif-sur-Yvette), Joel Hirschi (National Oceanography Centre, Southampton), Alex Piotrowski (University of Cambridge), Ed Hathorne (MARUM), Tom Marchitto (University of Colorado), Andreas Mackensen (Alfred-Wegener-Institut für Polar- und Meeresforschung, Bremerhaven), Ben Hickey (Oxford University), Wolfgang Berger (Scripps Institution of Oceanography), Mea Cook (Woods Hole Oceanographic Institution), Cristiano Chiessi (MARUM/INPE, São Paulo), Thomas Arsouze (LSCE, Gif-sur-Yvette), Jörg Lippold (Heidelberg Universtity), Jeanne-Marie Gherardi Scao (Bjerknes Centre, Bergen), Michael Sarnthein (University of Kiel), Ulysses Ninnemann (Bjerknes Center, Bergen), Trond Dokken (Bjerknes Centre, Bergen), Mara Weinelt (University of Kiel), Babette Hoogakker (University of Cambridge), Matthias Prange (University of Bremen), Marcus Gutjahr (University of Bristol), Olivier Marchal (Woods Hole Oceanographic Institution), Kevin Oliver (Open University), Martin Butzin (GEO Bremen), Dierk Hebbeln (MARUM), Ute Merkel (GEO Bremen), Mahyar Mohtadi (GEO Bremen), Gesine Mollenhauer (MARUM), Matthias Prange (MARUM), Janet Rethemeyer (GEO Bremen), Michael Schulz (MARUM), Stephan Steinke (MARUM), Jan-Berend Stuut (MARUM), Katrin Zonneveld (MARUM), Andre Paul (MARUM), Stefan Mulitza (MARUM)
Web site "Glacial Ocean Atlas"
http://www.glacialoceanatlas.org/
Conference Booklet
Templates for individual Proxies:
Benthic_Stable_Isotopes_LGM_Sep_08.xls
Template for benthic d18O/13C
Please feel free to suggest templates for other proxies
Accommodation
We made reservations for all invited participants (for a single room including breakfast from November 4th to 7th) in the Hotel Schaper-Siedenburg in the city center. The tram (tram stop ca 100 m away from the hotel) takes you in about 15 min to either the University or the Airport. The hotel bills will be paid directly by MARUM
Travel Information:
Child Care
Is available here
Contact: 
Last update: September 8, 2008
André Paul
Stefan Mulitza