The Oceans

Basics

Unit 2
Nutrients in the oceans 

On land it's easy to see that different areas have very different amounts of plant growth. The tropical rain forests have the most biological growth and the deserts have the least. Although it's not so easy to see, it's similar in the oceans. Oceanographers call the desert areas of the oceans the OLIGOTROPHIC regions. Oligo is the Greek word for small and troph is derived from the Greek for "to feed" so the name oligotrophic simply means an area with little food. Low levels of the major plant nutrients, nitrogen and phosphorous, in these areas means that little grows.  In this unit we will look at where these nutrients come from and how phytoplankton grow in the oceans.

Large inputs of nitrogen and phosphorous from land make coastal waters the most biologically active region of the ocean. Most of these nutrients come from human activities. Areas with excess nutrients are known as EUTROPHIC regions (based on the Greek for "to nourish"). Large amounts of phytoplankton growth in these areas can cause eutrophication problems and we will discuss these in this Unit.