seasons were processed to obtain the typical conditions of the
Gulf with respect to the rest of the Pacific coast of Costa Rica
(Fig. 2). During the rainy season, the inner gulf is warmer than
adjacent oceanic and coastal areas (Fig. 2(a)), whereas during
the dry season it tends to be cooler than the southwest coast of
Costa Rica (Fig. 2(b)). Waters inside the estuary have a difference
of ∼1.5 °C between seasons. Chl a concentration in the Gulf of
Nicoya was about five times higher than in any adjacent coastal
and oceanic areas at all times despite evident differences in SST
between seasons (Fig. 2(c), (d)). Mean chl a values in the rainy
season reached 18 mg m−3. These images confirm the high and
constant productivity of this tropical estuary compared with the
rest of the Costa Rican coast.