Experiments were carried out during a period when SACW could possibly influence the coastal site (experiment 1) (March-April) as well as when no influence of SACW was expected (experiment 2) (June-July).
Although several studies have examined the phytoplankton composition in coastal and oceanic regions of southern Brazil (citations in Soares 1983), none have focused on the phytoplankton composition of subsurface intrusions of SACW.
The current study suggests that growing scallops below the thermocline during the SACW intrusion may not necessarily be beneficial, as other concurrent factors may neutralize the benefits of enhanced food levels.
Such spatial variation in temperature and chlorophyll-a is in agreement with the patterns reported in other studies for the inner continental shelf of southern Brazil when SACW is present (Brandini 1990, Borzone et al.
Penetration of SACW onto the continental shelf has been related to situations in which prevailing winds blow offshore, generating a cross-shelf circulation toward shore in the deeper layers (Castro & Miranda, 1998).
The higher percent PIM near the bottom recorded in experiment 1, but not in experiment 2, is possibly associated with SACW, suggesting that during the process of SACW intrusion into the lower layer across the continental shelf, a frictional shear on the substrate resuspends bottom sediments, resulting in the higher PIM in the SACW.