Variability in the Distribution of Chlorophyll-a and Primary Production in the Argentine Sea using Field and Satellite Estimations

LUTZ, V.; SEGURA, V.; DOGLIOTTI, A.I.; GAGLIARDINI, D.A.; BIANCHI, A.A.; BALLESTRINI, C.F.

Barga, Italia

Conferencia; Ocean Optics XIX; 2008

The Argentine Sea, specially its extended shelf-break, appears as one of the most brightly colored areas in satellite images of chlorophyll-a (chla). This is indeed an area rich in marine resources, such as commercial fish, marine mammals, and seabirds. Scarce field programs have been performed to study in more detail the productivity of this region. A project to study chla distribution, optical properties, and primary production involving three cruises (during spring, summer, and winter) in an extensive area of the Argentine Sea was carried out in the period 2005-2006. We show here the wide spatial and temporal variability found in the chla distribution during these cruises. We focus then in the spatial variability observed during spring 2005 in the chla concentration, the [chla/in vivo-fluorescence] ratio, and the primary production. At this period strong phytoplankton blooms had developed in some areas, with surface chla concentrations and integrated production that ranged from ~ 0.40 to 28.00 mg m-3 and from ~ 275 to 5477 mg C m-2 d-1, respectively. The [chla/in vivo-fluorescence] ratio at the surface showed also a variation of two orders of magnitude. These results indicate the extreme variations in environments and phytoplankton diversity of this region of the South West Atlantic. As a first approach we compare and discuss differences encountered between field and satellite (using a standard algorithm with fixed parameters) estimations of primary production.