Chapter Summary and Essay Questions
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Chapter 26 Environmental Microbiology
Chapter Summary and Essay Questions This chapter discusses water microbiology and elemental recycling in the environment. Chapter 26 opens with discussions on the microbial floras of unpolluted, polluted, and marine environments. It then outlines the infectious diseases that water transmits and continues with descriptions of water purification and sewage treatment. Biofilms, which carry out much microbial activity, are described and as is their role in bioremediation and disease causation. Bacteriological tests used to determine microbe number are also described. The chapter closes with descriptions of the roles of microorganisms in the carbon, sulfur, and nitrogen cycles. On completing the chapter, you should be able to answer the following questions: a. Compare ground and surface waters with reference to their origin and microbial content. b. Write short essays on unpolluted, polluted, and marine environments, comparing the types of microorganisms found in each environment. c. Discuss the origin of physical, chemical, and biological pollution of waters. d. Explain the meaning of BOD, and outline the test by which it is determined. e. List a number of bacterial, viral, and protozoan diseases that can be transmitted by contaminated waters. f. Describe the three major steps involved in the purification of waters by major municipalities. g. Compare the basis for sewage disposal in the cesspool and the septic tank. h. Outline the process involved in the treatment of commercial sewage during the primary, secondary, and tertiary stages. i. Assess the importance of biofilms in a watery environment. j. List the major steps involved in the performance of the standard plate count technique and the most probable number test as they are used in water bacteriology. k. Assess the role of microorganisms in the earth’s carbon cycle. l. Briefly describe the sulfur cycle as it occurs in the soil. m. Assess the importance of soil microorganisms to the nitrogen cycle, indicating where microorganisms are important and highlighting their role in the process of nitrogen fixation.