39
may transport photosynthetically produced organic matter to the seafloor, where
it is rapidly consumed and incorporated into benthic biomass or trapped in sediments (Berkenbusch et al. 2011). The convergence of waters at ocean fronts may
result in relatively intense downwelling compared to typical rates in other regions.
These intense vertical velocities may be significant in determining the exchange
rate of heat, carbon dioxide, and other gases between the atmosphere and the deep
ocean (Ferrari 2011).
The hydrography of the Southern Ocean is characterized by a series of zonal
fronts which generally circle the Antarctic continent. Models and observational
studies suggest that the Southern Ocean is an important site for sequestering
atmospheric CO 2 . Lowest CO 2 values concomitant with maxima of chlorophyll
were detected near fronts in the Southern Ocean (Robertson and Watson 1995;
Daly et al. 2001). In the Argentine Sea, the near-shore waters are a source of CO 2
to the atmosphere while the midshelf region is a CO 2 sink. The transition between
source and sink regions closely matches the location of tidal fronts, suggesting
that phytoplankton blooms near the stratified side of the fronts draw the ocean’s
CO 2 to very low levels thus promoting further uptake. At the shelf break front the
CO 2 flux to the ocean is the largest (Bianchi et al. 2005, 2009; Schloss et al. 2007).
CO 2 sequestration is the result of complex interactions of biological; biogeochemical and oceanographic processes; therefore high phytoplankton standing
stocks do not necessarily imply high CO 2 sequestration; however, it has been
shown that at least some fronts are an important element of the ocean-atmosphere
coupled climate system (Ferrari 2011).
4.3 Climate Change
may transport photosynthetically produced organic matter to the seafloor, where
it is rapidly consumed and incorporated into benthic biomass or trapped in sediments (Berkenbusch et al. 2011). The convergence of waters at ocean fronts may
result in relatively intense downwelling compared to typical rates in other regions.
These intense vertical velocities may be significant in determining the exchange
rate of heat, carbon dioxide, and other gases between the atmosphere and the deep
ocean (Ferrari 2011).
The hydrography of the Southern Ocean is characterized by a series of zonal
fronts which generally circle the Antarctic continent. Models and observational
studies suggest that the Southern Ocean is an important site for sequestering
atmospheric CO 2 . Lowest CO 2 values concomitant with maxima of chlorophyll
were detected near fronts in the Southern Ocean (Robertson and Watson 1995;
Daly et al. 2001). In the Argentine Sea, the near-shore waters are a source of CO 2
to the atmosphere while the midshelf region is a CO 2 sink. The transition between
source and sink regions closely matches the location of tidal fronts, suggesting
that phytoplankton blooms near the stratified side of the fronts draw the ocean’s
CO 2 to very low levels thus promoting further uptake. At the shelf break front the
CO 2 flux to the ocean is the largest (Bianchi et al. 2005, 2009; Schloss et al. 2007).
CO 2 sequestration is the result of complex interactions of biological; biogeochemical and oceanographic processes; therefore high phytoplankton standing
stocks do not necessarily imply high CO 2 sequestration; however, it has been
shown that at least some fronts are an important element of the ocean-atmosphere
coupled climate system (Ferrari 2011).
4.3 Climate Change