Environmental Micro

Question 1

list some functions of microbes in the environment

Answer 1

• produce oxygen
• decompose organic matter
• modify substances for use by others
• produce food (photo- and chemoautotrophs) for chemoheterotrophs

Question 2

role of photolithoautotrophs

Answer 2

• essential producers of organic material
• convert light to chemical energy
• this chemical energy can be used (eaten) by chemoorganoheterotrophs

Question 3

role of chemolithoautotrophs

Answer 3

• chemical transformation of elements
• contribute to carbon and nitrogen cycles

Question 4

role of chemoorganoheterotrophs

Answer 4

• contribute to carbon and nitrogen cycles
• used in industry to make foods and beverages (cheese, yogurt, etc.), used in medical products (antibiotics)
• these are also pathogens!

Question 5

describe the carbon cycle

Answer 5

• chemolithotrophic and photosynthetic organisms (plants) for CO2 into organic molecules like sugar
• chemoorganoheterotroph eats plants
• chemoorganoheterotroph dies –> chemoorganoheterotroph (microbe) facilitates the decaying process using aerobic respiration, fermentation, or anaerobic respiration –> oxidize organics, produce CO2 as byproduct

Question 6

briefly summarize relationship between autotrophs and heterotrophs

Answer 6

• autotrophs use CO2 to create organics (sugars, fats, proteins)
• heterotrophs use organics to release CO2

Question 7

eutrophication

Answer 7

• in fresh water
• addition of nutrients which are in normally rate-limiting quantities in water (so, this is pollution)
• this depletes water of oxygen, kills fish

Question 8

sewage treatment: nutrient removal from water

Answer 8

• removes biological oxygen demand
• BOD measures the amount of oxygen needed for microbes to degrade the organic material in water
• the more organic material, the more BOD

Question 9

primary sewage treatment

Answer 9

allows large material to settle out, forming sludge, removes 20-30% of BOD

Question 10

secondary sewage treatment

Answer 10

• biological (microbial) removal of organic material and most pathogens
• aerobic and anaerobic degradation of the organic materials in the water by the microbes

Question 11

tertiary sewage treatment

Answer 11

• removal or inorganic nutrients, viruses, chemicals, and toxins
• this is in a municipality with resources