Resumen de Cyanobacteria distribution across the Western Mediterranean divergence: a proof of pigment adaptation in different light conditions
The vertical distribution of C-phycoerythrin (CPR) and the photosynthetic prokariotic picoplankters Synechococcus spp. across the Western Mediterranean divergence was studied twice during the year 1986 (June and November). The maximum concentration of CPR in the water column occurred at the same depth as the DCM (deep chlorophyll maximum). However the maximum concentration of Synechococcus spp. were located at different depths. No correlation was detected between their vertical distribution, the nutricline and the light gradient, contrary to the nanoplanktonic fraction of the phytoplankton. The contribution of the cyanobacteria picoplankters to deep pigment maxima consists in a physiological process of pigment adaptation. The increase in CPR per cell with depth and with decreasing irradiance in the late autumn samples suggests the existence of ontogenetic pigment adaptation to light intensity with the available environmental nutrients.
