Ecological Zonation of Phytoplankton and Biomass Based on Bio-Optical Parameters off Baja California during Three Summer Seasons

An ecological zonation of phytoplankton was determined from its normalized spectral absorption shape (aphn) during the summers of 2001-02-03 off the west coast of Baja California. In the first two seasons, the highest abundances of the main taxonomic groups of phytoplankton were detected towards the coastal stations, but for 2003, diatoms showed higher abundances towards the oceanic region. The ecological provinces (Pv) were the footprint of the zonation in the structure of the phytoplankton community; likewise, it was observed that the spectral shape was independent of the chlorophyll-a (mg·m-3). The effect of coastal upwelling south of Vizcaino Bay favored the increase of phytoplankton cells. However, the composition of the community decreased in cells abundance and diversity due to the influence of the phenomenon called El Nino “debil” reported to the south of the California Current for the years 2002-03.