Research
Non-belspo (2004-2007)
Export of organic carbon from the oceanic surface mixed layer and mineralisation in the twilight zone (VERTIGO)
Project description
The drawdown of carbon dioxide
from the atmosphere by the ocean constitutes the largest sink
for anthropogenic CO2. While this is due to a large extent to
physico-chemical processes (the solubility pump) that redistribute
CO2 in the ocean, biological activity is another important mechanism
for carbon translocation from the surface mixed layer to the
ocean’s interior. This project aims at improving our understanding
of the processes that impact on the export of organic carbon
from the surface mixed layer via the biological pump and which
drive mineralization in the ocean’s interior. This knowledge
is essential for the assessment of the ocean’s sequestration
efficiency of anthropogenic CO2.
Our strategy is to compare oceanic regions which differ significantly
in terms of ecological characteristics such as nutrient uptake
regime; nutrient supply and nutrient limitation; phytoplankton
community composition; grazer community and grazing pressure;
length of growth season and mineralization length scales (Southern
Ocean – North Pacific NE Atlantic). We propose to constrain
the uncertainties on export production and mineralization in
the twilight zone by confronting three different approaches for
export production assessment in functionally contrasting oceanic
regions. These three approaches are: (1) New production via 15N
tracer techniques and modeling; (2) The 234Th-deficit technique
and (3) Seasonal increase of mesopelagic particulate Ba stocks.
Project team
Project Coordinator: Frank Dehairs
Involved research groups
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution
- Antarctic Climate and Ecosystem Cooperative Research Centre
- Lawrence Livermore National Laboratories
- Centre for Chemical and Physical Oceanography, University of Otago
Involved partners:
Partner 1:
Dr. Ken O. Buesseler
Department Chair and Senior Scientist
Department of Marine Chemistry and Geochemistry
Woods Hole Oceanographic Institution
Woods Hole MA, 02543 USA
Phone: 508-289-2309
FAX: 508-457-2193
e-mail: kbuesseler@whoi.edu
cafethorium.whoi.edu
Partner 2:
Prof. Thomas W. Trull
University of Tasmania - CSIRO Marine Research
Antarctic Climate and Ecosystem Cooperative Research Centre
Hobart
Tasmania
Australia
Phone: 61 3 62 262988
Fax: 61 3 62 262973
e-mails: Tom.Trull@utas.edu.au, Tom.Trull@acecrc.org.au,
Tom.Trull@csiro.au
www.acecrc.org.au
www.imas.utas.edu.au/about-imas
www.cmar.csiro.au
Partner 3: Prof. James K.B. Bishop
EO Lawrence Livermore National Laboratory
University of California, Berkeley
M/S 90-1116, One Cyclotron Road
7000 East Avenue
Livermore, CA 94550
USA
Phone (510) 495-2457
Fax (510) 486-5686
e-mail: JKBishop@lbl.gov
Partner 4: Dr. Philip Boyd
Centre for Chemical and Physical Oceanography
Department of Chemistry
University of Otago
PO Box 56, Dunedin, New Zealand
Phone: (64)(03) 479-5249
Fax: (64)(03) 479-7906
e-mail: pboyd@alkali.otago.ac.nz