Question

• Question 1

  	The rate-limiting, or slowest, step in the methanogenic biodegradation of solid substrates, such as organic wastes and animal manures is:
  	Answers: a. Methanogenesis b. Fermentation c. Respiration d. Hydrolysis e. Photosynthesis

• Question 2

  	Methanotrophic bacteria:
  	Answers: a. oxidise methane to produce carbon dioxide b. produce methane by photosynthesis c. are found mainly in aquatic environments d. are strictly anaerobic bacteria e. produce methane by oxidation of organic compounds

• Question 3

  	Decomposition is mainly driven by:
  	Answers: a. Algae b. Facultative anaerobes c. Chemolithotrophs d. Heterotrophs e. Photosynthesisers

• Question 4

  	In aquatic environments, which of the following statements is true for primary production:
  	Answers: a. is mainly palnt-based b. is almost exclusively bacterial and algal c. occurs mainly in sediments d. requires organic substrates e. occurs mainly in freshwater

• Question 5

  	Which of the following statements is true in relation to biogeochemical cycles:
  	Answers: a. Animals can fix carbon and nitrogen from the bioavailable reservoirs b. Carbon and nitrogen present in rock are normally bioavailable c. Organic carbon and organic nitrogen are the largest bioavailable reservoirs on earth d. The bioavailable reservoirs of carbon and nitrogen are atmospheric gases e. The bioavailable reservoir is always the largest reservoir of nutrient elements on earth

• Question 6

  	Microbial Ecology is the study of:
  	Answers: a. The interactions between microorganisms and their environment b. Biogeochemical cycles c. Microbial biodiversity d. The effect of the environment on microbial growth e. The life cycle of microorganisms

• Question 7

  	The recently described process of "Comammox" refers to:
  	Answers: a. The complete conversion of ammonia to nitrate by a single organism b. The partial denitrification of nitrate to produce nitrous oxide c. The oxidation of ammonia to nitrite d. The process of nitrogen fixation under anaerobic conditions e. The oxidation of nitrite to nitrate

• Question 8

  	Which of the following statements about the carbon cycle is true?
  	Answers: a. The largest bioavailable reservoir is atmospheric methane b. The reactions of the carbon cycle are not affected by temperature c. The reactions of the carbon cycle are not affected by oxygen availability d. It involves the uptake and evolution of carbon dioxide and methane e. it requires aerobic conditions to proceed

• Question 9

  	Which of the following statements is true about anaerobic digestion?
  	Answers: a. it involves aerobic respiration b. it cannot be used to produce biofuels c. it requires oxygen to proceed d. it can be carried out using aerobic bioreactor systems e. it involves the microbiological process of methanogenesis

Answer 1

Answer 1: a. Methanogenesis

The production of methane via microbes (methanogens) by utilizing carbon (as electron acceptor) is known as methanogenesis. For example Biogas.

Answer 2: a. oxidise methane to produce carbon dioxide

A microbial process to generate energy and assimilize the carbon from methane is defined as methane oxidation. Oxidation of methane is carried out by methanotrophs. Oxidation of methane results in the production of carbon dioxide.

Answer 3: b. Facultative anaerobes

Answer 3: b. is almost exclusively bacterial and algal