ID 35 : An international study of the biogeochemical cycles of Trace Elements and Isotopes in the Arctic and Southern Oceans (IPY-GEOTRACES)

Short description of the core IPY project:
GEOTRACES is being set up to greatly expand our understanding of the distribution and circulation of trace elements and their isotopes (TEIs) in the ocean. IPY offers a unique opportunity to include the polar oceans in this global GEOTRACES study, with special focus on synoptic studies of the Arctic and Antarctic Oceans.

Description of a BONUS, a component of GEOTRACES-IPY:
Biogeochemistry of the southern Ocean: interactions between NUtrients, dynamics, and ecosystem Structure (BONUS-GoodHope); Activity ID No: 584.

BONUS will contribute to acquiring key data sets on the present dynamics, circulation and biogeochemistry of the SO (sources, sinks, transport of nutrients and TEI). BONUS will help to understand how polar ecosystems respond to physical and chemical forcing. Integration of BONUS results into biogeochemical-physical coupled models at different scales (1-D to 3-D) will help to improve our projections of future change (Theme 2). Within Theme 3, the focus on subduction and ventilation of SAMW/AAIW is of great importance because of their role in the transportation of nutrients to the global ocean.

Period and timing of the project:
-

Belgian partners:
- Vrije Universiteit Brussel, Analytical and Environmental Chemistry
- Royal Museum for Central Africa, Mineralogy and Geology
- Université de Liège, Océanographie

Description of the Belgian contribution:
The general scientific approach is based on the coupling of i) physical oceanography ; with ii) the biogeochemistry, including nutritive trace metals (Fe, Co, Zn, Cu, Cd, and probably Mn), in water-column, atmosphere and sediments ; iii) the study of selected trace elements and isotopes, that are tracers of lithogenic sources, circulation, ageing and ventilation of water-masses, and which are also needed to quantify the particulate export fluxes to the deep ocean ; and iv) the development of combined circulation and biogeochemical models that integrate the large and regional scales.
The Belgian contribution will focus primarily on the following tracers and proxies: Si natural stable isotope ratios; barium-barite proxy and 234Th carbon export. In addition, the anthropogenic CO2 penetration through subduction and ventilation of SAMW/AAIW will be assessed.

Related campaigns with Belgian contribution:
- IPY BONUS; R/V Marion Dufresne (Jan. – Feb. 2008)
- IPY GEOTRACES SR3; R/V Aurora Australis (Nov. - Dec. 2007)

Other resources:
- www.ldeo.columbia.edu/res/pi/geotraces/
- classic.ipy.org/development/eoi/details.php?id=584
- www.antarctica.ac.uk/Resources/BSD/ICED/documents/BONUS_GOODHOPE.pdf
- classic.ipy.org/development/eoi/details.php?id=426