Elements of support to estimate total and new primary production in the Gulf of California based on satellite data

Abstract

High rates of primary production support the great animal biodiversity of the Gulf of California. One of the main limitations to estimate total (PT) and new (PNEW) primary production by 14C and 15N bottle incubations, respectively, is the small number of point samples generated for a particular area, and with very poor time coverage. Satellite ocean color sensors offer an alternative to estimate phytoplankton production rates in the oceans with an ample spatial-temporal variability that is not possible to cover with research vessels. With ocean color sensors in orbit, scientific expectations remain to improve ocean primary production models. Parameters used by these algorithms fall into three categories: environmental, ecological, and physiological. A review is given on studies that have generated information on these parameters for Gulf of California waters, and opportunities for new research are highlighted. Satellite surface pigment (Chls) and irradiance data (PARsat) need to be associated to vertical profiles (Chlz and PARz) generated with a Gaussian distribution function and Lambert-Beers law, respectively. A detailed description is given of the parameters that characterize this Gaussian function and a vertical attenuation coefficient of PAR variable with z, for different seasons and regions within the Gulf of California. The weakest part of modeling primary production are the photosynthesis-irradiance (P-E) curve parameters: the initial slope, assimilation number, and quantum efficiency, and these give us an opportunity for new research. Summer data to characterize all the set of parameters needed for modeling primary production based on satellite data are the scarcest.