Figure 2 shows the distribution of surface temperature observed by thermograph at 4 m of depth. When analyzed together with the hydrographic profiles it seems that the lower temperatures inshore off Suriname results from mixing with cool upwelled water. A similar picture, but with somewhat lower surface temperatures was found in February. Off Gyuana the cool water does not seem to reach the surface, but there are again some signs of cooler inshore surface water off Venezuela, Orinoco.
Figure 3 shows the distribution of temperature, salinity and oxygen in the hydrographical profiles. For that off the Maroni River the isolines for the three types of observations rise over the shelf edge and lifts further shorewards demonstrating upwelling and transport shorewards of intermediate water, a situation demonstrated in all four surveys. The distribution of salinities shows no evidence of the offshore low-salinity water of Amazon origin in the surface which was present in the three previous coverages.
The upwelling is less convincingly demonstrated in the profile off Guyana, but is again evident in that off the Orinoco.
There is low salinity water inshore in this section demonstrating discharge of the Orinoco as in the first survey.
