On the Photosynthetic Potential in the Open Oceans

Abstract

The photosynthetic potential of the main primary producers in open oceans (phytoplankton) is quantitatively assessed using Jerlov’s optical classification for ocean waters. To consider more accurately the inhibitory effect of ultraviolet radiation on photosynthesis, two biological weighting functions were used, one for equatorial and tropical phytoplankton, and the other for the subarctic one. Results show similar photosynthetic potentials in equatorial and tropical regions, and smaller photosynthesis rates for the subarctic zones. On the other hand, for the same latitude, there were considerable differences in the
photosynthetic potential between the clearest open ocean waters (optical type I) and the darkest (optical type III), being around five times greater in the clearest open ocean waters.