Primary Production in the Patagonian Continental Shelf and Shelf-break region: Improved Estimation using Satellite-based Models

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

Conferencia; Ocean Optics XX; 2010

The Patagonian Continental Shelf (PCS) and shelf-break regions comprise a large and rich biological area of the ocean; therefore, the interest in improving the estimation of primary production using a satellite approach. Field studies performed during spring 2005 showed a high spatial variability in the (chlorophyll) biomass-normalized photosynthetic parameters ( and BmPBα). The overall variability in both parameters was similar (coefficient of variation, CV~70%); however, the variability in chlorophyll concentration (Chl-a) was higher (CV=148%), evidencing the patchy characteristic of the spring blooms in the PCS. Using field measurements, different and relatively simple (non-spectral and vertically homogeneous biomass) models were tested. The Platt and Sathyendranath (Science, 241:1613–1620, 1988) model showed the best results, and was selected as the ‘local algorithm’. To estimate the photosynthetic parameters required by the local algorithm to compute primary production on a larger (regional) scale, correlations between the measured parameters and remotely-sensed properties, such us temperature and chlorophyll, were tested, but no significant relationships were found. Therefore, a partition of the PCS into biogeochemical regions approach was performed based on remotely-sensed sea-surface temperature, chlorophyll concentration, normalized water-leaving radiance at 551 nm, photosynthetically active radiation (PAR) and bathymetry. The estimation of primary production using averaged field parameters within each biogeochemical region was improved with respect to that estimated using fixed parameters for the whole PCS (relative and absolute percent difference, RPD ~ 8 % and APD ~ 47 %).