IRON SUPPLIED TO THE SOUTHERN OCEAN THROUGH RECENT VOLCANIC ASH DERIVED FROM THE PATAGONIAN ANDES.

SIMONELLA L.; PALOMEQUE M.; MONTE M. L.; DESIMONI, J.; KUPCZEWSKI, M.; ROSALES A.; GAIERO, D.

Settle

Conferencia; SOLAS-Open Science Conference; 2012

SOLAS

The Southern Ocean represents about 20% of total global ocean and plays a major role in the distribution of carbon dioxide between the atmospheric and oceanic reservoirs. This oceanic region is atypical as it exhibits plenty of major plant nutrients in surface water, but somehow the photosynthetic CO2 fixation and plant biomass is low. Due to its geographic position and the dominance of westerly winds, Patagonia is viewed as a key area for supplying key nutrients (e.g., Fe) through mineral dust but also by periodically exportation of volcanic ash to this HNLC (high-nutrient low-chlorophyll) oceanic region. In this contribution we evaluate the Fe-mobilization behavior of pristine volcanic ash from three modern Patagonian volcanic eruptions (Hudson, 1991, Chaiten, 2008 and Puyehue, 2011) by using leaching and flow-through reactor experiments. We also evaluate fluxes of available Fe to the ocean and the probable effects over the marine biogeochemical iron-cycle.