Student glossary of key terms that includes definitions, pictures, examples, and audio clips of proper pronunciation.

Diffusion: Movement of molecules from areas of high concentration to areas of low concentration across a membrane.


Example: If there is 75% Oxygen on one side, and 25% Oxygen on the other, the molecules from the side with higher concentration move to the side that has less concentration, until they reach equalization.

Eutrophication (audio)- an increase in chemical nutrients (typically nitrogen and phosphorous) in an ecosystem; leads to excessive plant and algae growth which reduces oxygen availability for other organisms in the ecosystem.

external image eutrophication.jpg

Eutrophication can be a natural process in some ecosystems such as estuaries where nutrient runoff is high. However, it is most often the result of pollution from fertilizers and sewage.