The answers to the questions on the previous page are:

• Free swimming oceanic forms are called pelagic.
• Most life in the open ocean is limited to the photic zone.
• Phytoplankton are the main producers in the open ocean.

The interactions between the atmosphere and ocean are very complex. The force of easterly trade winds on the ocean surface causes westerly equatorial currents north and south of the equator. When these encounter the east coasts of Asia and the New World they are deflected north and south. The currents then turn eastward at high latitudes, strike the west coasts of the Americas, Europe, and Africa, and then return to the equator. The effects of these currents are such that there are vast clockwise circulations in the north Pacific and Atlantic Oceans and counter clockwise circulations in the oceans in the southern hemisphere. Temperature and light is the paramount factor in determining the distribution of organisms in the ocean. It varies with locations, with seasons, and depth. The ocean is categorized into zones based on penetration of light (photic and aphotic), distance from shore (intertidal, neritic, and oceanic), and open water or bottom (pelagic and benthic). The abyssal zone is the aphotic region of the benthic zone. Draw a figure in your notes showing these various zones and explain what type of organisms would be present in each of these zones.

Activity: Write a paragraph describing which environmental factors are responsible for the characteristic adaptations demonstrated by the plants and animals in the ocean and give examples of the flora and fauna which may be found in this ecosystem’s trophic levels.

a. C B A D E

b. B A C D E

c. C B A D E

d. C A E B D

e. A D B C E