The two images below show variations in primary productivity based on
satellite measurements of chlorophyll pigment. Red colors indicate high
values and purple colors indicate low values (see colorbar scale below).
Black areas are parts of the ocean where no data were collected. Two factors
affect the amount of primary productivity in the ocean: light and nutrients.
Light changes seasonally, particularly at high latitudes. High nutrient
levels are often associated with areas of upwelling currents and low levels
are often associated with downwelling currents. In the displayed images,
notice how the productivity values relate to the oceanic currents we studied
in another exercise. (NOTE: To obtain larger-sized images (each are about
330K in size), double-click on the displayed images.)
a.) Describe the locations in the ocean that have high productivity
values (i.e., high pigment concentrations) and explain why values are high
at these locations.
b.) Describe the locations in the ocean that have low productivity values and explain why values are low at these locations.
c.) Compare the winter and summer images in terms of high and low productivity regions.