EXTENDING YOUR KNOWLEDGE

These questions are more general than the Interactive computer corrected questions. In fact, many of the questions may not have one correct answer. The purpose of these questions is to provide the users of the RAK with an opportunity to evaluate and apply their understanding of the physical and chemical characteristics of rivers.

In order to answer these questions you can return to the material in the main text to review information on each topic, you can get some ideas about the answer by discussing the issues they raise with some of your colleagues, or you can utilize the RAK web site and Bulletin Board to get help from other RAK users or from one of the content experts that participated in the development of the RAK.

1. Identify and describe the most important physical and chemical components of river ecosystems.

2. Explain the critical role of oxygen for maintaining the health of river ecosystems and describe the role temperature plays in making oxygen and other chemical compounds available to aquatic organisms.

3. Describe what is meant by the classification of river waters into blackwater, whitewater and Clearwater and explain the relationship between these classifications and the availability of organic and inorganic materials in different parts of a river.

4. Discuss the impacts of the following factors on the plants and animals of river ecosystems:

· Temperature
· Alkalinity and acidity
· Light and shade
· Substratum
· Flow hydraulics
· Precipitation

5. Discuss some of the most important ways in which pollution and other impacts from human activity have a negative influence on the physical and chemical characteristics of rivers.