Improving the estimation of primary production using remote sensing data in the Argentine continental shelf and shelf-break regions

DOGLIOTTI, A. I.; LUTZ, V.; SEGURA, V.

Liege

Congreso; 45th International Liège Colloquium on Ocean Dynamics: ?Primary Production in the Ocean: from the synoptic to the Global Scale?; 2013

In order to estimate primary production on a synoptic scale using satellite information,four methods were tested to assign photosynthetic parameters that characterize thephotosynthesis?irradiance relationships: (1) the nearest neighbor method (NNM), (2) staticand, (3) dynamic partition into biogeochemical regions, and (4) average values of measuredparameters. The required photosynthetic parameters were obtained during three oceanographic cruises conducted in the Argentine shelf and shelf-break regions during spring 2005, summer and winter 2006 by performing photosynthesis-light incubation experiments. Despite some variations in the performance according to the season, the NNM and the use of dynamic provinces emerged as the preferred methods for parameter assignment. Composite synoptic maps of primary production for each cruise were calculated, showing a high spatial variability within the region. Seasonal variability in the primary production for the whole continental shelf and for selected ecologically relevant regions, such as the shelf-break, were extracted from monthly images of primary production computed over an annual cycle using MODIS-Aqua derived chlorophyll-a concentration. The high mean primary production estimated over the shelf-break showed values comparable to other well-known productive zones of the world oceans, such as the Benguela system. A first estimation of the total amount of carbon fixed in the shelf-break area showed that the annual production of the Argentine shelf and shelf-break regions represent a large percentage of the mean production of the global ocean. Results will be compared to those obtained by previous global estimations for this region.