(a.) The diagram below illustrates coastal upwelling along the west coast of South America (Southern Hemisphere ). Strong southeasterly winds (red arrows) prevail along the coast of southern Ecuador and Peru. These winds drag the surface water northwestward (left of the wind's motion) and cold, nutrient-rich water (dark blue) wells up along the shore of the eastern Pacific.
Make a simple sketch of the California coastline (Northern Hemisphere ; a map view of the coast is all that's needed). Draw arrows (and label them) to illustrate (1) the direction of the wind and (2) the direction of the surface water that would create upwelling currents off the coast of California.
Phytoplankton are microscopic plants (for example, diatoms) that are the base of the food chain in most of the ocean. Pigments (primarily chlorophyll) are used by plants to do photosynthesis. Pigment concentrations reflect the amount of plants in the water and are a measure of biological productivity in the ocean. Primary productivity is the growth of plants and secondary productivity is the growth of animals, which make up the higher levels of the food chain, and which depend on the primary production of plants.
Chlorophyll pigment, and also water temperature, can be measured by satellites orbiting the earth. False color is added to highlight different concentration values and different ocean temperatures.
Chlorophyll pigment image on left: red indicates high values; blue-magenta indicates low values (also see color bar).
Temperature diagram on right: red indicates warm temperatures, blue-magenta indicates cool temperatures.
Explain the distribution of pigment concentrations and temperatures along the California coast, in light of what you have learned about upwelling currents.