Figure 2 shows the hydrographical sections off the Peninsula of Guajira, off Riohacha and off the Rosario Island. The profile off Guajira shows evidence of a light upwelling, whereas the isolines of the Riohacha section show no sign of vertical movementes of the water masses. In the Rosario section the hydrographical situation is characterized by an upper layer of light water inshore with low salinity and high temperature, probably effected by the discharge from the Magdalena river.
