HR: 1340h
AN: OS43A-0537 [Abstracts]
TI: (More) Biogenic Barium and Organic Carbon Relationships on the Continental Margin: a Study From the
Alboran Sea (Western Mediterranean)
AU: * Sanchez-Vidal, A
EM: asanchez@geo.ub.es
AF: GRC Geociencies Marines, Dept. Estratigrafia, Paleontologia i Geociencies Marines. Universitat de
Barcelona, Barcelona, 08028
Spain
AU: Collier, R
EM: rcollier@coas.oregonstate.edu
AF: College of Oceanic and Atmospheric Sciences, Oregon State University. Ocean Admin. Bldg., Corvallis, OR
97331-5503
United States
AU: Calafat, A
EM: tonim@geo.ub.es
AF: GRC Geociencies Marines, Dept. Estratigrafia, Paleontologia i Geociencies Marines. Universitat de
Barcelona, Barcelona, 08028
Spain
AU: Fabres, J
EM: joan@geo.ub.es
AF: GRC Geociencies Marines, Dept. Estratigrafia, Paleontologia i Geociencies Marines. Universitat de
Barcelona, Barcelona, 08028
Spain
AU: Canals, M
EM: miquel@geo.ub.es
AF: GRC Geociencies Marines, Dept. Estratigrafia, Paleontologia i Geociencies Marines. Universitat de
Barcelona, Barcelona, 08028
Spain
AB:
The observed relationship between biogenic barium (bio-Ba) and organic carbon (Corg), and the relatively refractory nature of
barite in non sulfate reducing sediments have led to the consideration of barite as a proxy for both modern and past
biological processes. Beyond the uncertain phase partitioning between barite within total bio-Ba, recent studies have
revealed that the relationship between bio-Ba and Corg fluxes in margin systems and open ocean systems differs markedly. In
order to improve the knowledge of the behavior and significance of this component we present particulate bio-Ba fluxes
obtained from three instrumented arrays with sediment traps moored in a continental margin area: the Alboran Sea (Western
Mediterranean).
The results obtained provide important insights into the influence of the oceanographic structures (upwelling off the Spanish
coast, Western and Eastern Alboran Gyres), the intermittent fluvial discharge (southern Iberian Peninsula rivers) and the
local bottom topography on the formation and transport of bio-Ba. Increased bio-Ba export efficiency at the end of enhanced
productivity events suggest that the processes limiting bio-Ba formation in the area relate to the settling dynamics of
particles. The ballasting effect of the abundant lithogenic and carbonate particles during massive aggregation processes
during high productivity events may limit the decomposition of organic matter and enhance the transfer of particles rich in
Corg and relatively poor in bio-Ba to the deep sea floor. We have also observed lateral transport of freshly sedimented
material, including bio-Ba, from the continental slope to deeper areas. These results add to the growing caution in using
bio-Ba as a productivity proxy in such highly dynamic environments.
DE: 4805 Biogeochemical cycles (1615)
DE: 4825 Geochemistry
DE: 4875 Trace elements
DE: 4243 Marginal and semienclosed seas
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting