Environmental Microbiology 2023 with verified questions and answers

Environmental microbiology focuses on: *microbial activities that help maintain, sustain, or control life on earth *the natural role of microorganisms in the environment *the contribution to ecologic balance of... -water -soil -mineral (mineral cycles) Two agencies are EPA-environmental protection agency Department of agriculture Environmental (or ecological) microbiology: is the study of microorganisms in their natural habitat the environment has two components Biotic (living or dead) components Abiotic (nonliving) components Ecosystem: is the collection of organisms with their surrounding physical and chemical factors Ecosystem organization *biosphere: is the habitable areas of the earth *it includes: -Atmosphere (air) -Hydrosphere (water) -lithosphere (soil) Niche: describes the biological role of an organism within its community Mutualism: beneficial relationship Commensalism: nonharmful, one-sided relationship Synergism: two organisms cooperate to metabolize a substrate Parasitism: the parasitic organism harms the host organism Competition: one organism inhibits the other Predation: one organism ingests the other alive The Carbon cycle *Carbon exists in the mineral state and in the organic state in the bodies of organisms *Carbon also exists in much smaller amounts in the gaseous state as CO2, CO, and CH4 *Photosynthesis allows removal of CO2 from the atmosphere -CO2- Carbon dioxide -CO- Carbon monoxide -CH4- Methane The Carbon cycle continues... *During photosynthesis, phototrophs use energy from the sun to fix CO2 into organic compounds such as glucose Photosynthesis reaction: CO2 + H2O ---- C6H12O6 + O2 ^ Balanced: 6CO2 + 6H2O ------- C6H12O6 + 6O2 ^ The Carbon cycle continues.. *In the past 25 to 40 years, the production of CO2 in the atmosphere has steadily increased, leading to what is known as global warming/ climatic change -this could be caused by the increased usage of fossil fuels such as oil, coal, natural gas -resulting in the disruption of the delicate temperature balance of the biosphere Methane gas (CH4) plays a secondary role in the carbon cycle *however, the effects of CH4 combined with the other greenhouse gaqses may have a great contributing factor as CO2 What are "methanogens"? are bacteria that produce methane by breaking down substances What are examples of animal species where methanogens play an important role? Ruminants: 1. Cow 2. Goat 3. Sheep The following gases are believed to play a major role in the global warming or climatic change process *CO2 *CH4 *NO *CO *SO2 -all these gases are believed to trap certain amounts of heat in the atmosphere... Nitrogen cycle *the nitrogen cycle involves 4 processes and several types of microbes 1. Nitrogen fixation -N2 is converted to NO2, NO3, or NH4+ salts -Microbial fixation is achieved by symbiotic bacteria -formation of nodules on legume's roots 2. Ammonification -it is the bacterial breakdown of nitrogenous organic compounds to NH4+ 3.Nitrification -it's the conversion of NH4+ to NO2 and NO3 4. Nitrification -it is a multi-step microbial conversion of NH4+ back to N2 -several bacteria are involved in this process *Nitrogen is not toxic but ammonia is *NO2- Nitrite *NO3- Nitrate *NH4+- Ammonium Iron *NH3- Ammonia CAF-O Concentration Animal Feeding Operation Nitrogen (N2) gas is the most abundant gas in the atmosphere Soil Microbiology *the soil is a dynamic ecosystem that harbors a variety of microbes, plants, and animals *Acid-producing bacteria and lichens break down rocks and release minerals in the environment *The population of aerobic bacteria decreases and that of the anaerobic bacteria increases with the depth of the soil... Lichens: are symbiotic associations between fungi and algae Humus: is the layer of soil containing animal and plant tissues being broken down by microorganisms Rhizosphere: is the soil around plant roots, which supports the growth of microorganisms Mycorrhizae: are special symbiotic zones formed between certain fungi and some plant roots Microbes in water supplies *Importance of management of water supply in the prevention of disease ~most drinking water comes from rivers, aquifers, and springs ~potable water must be free of: -excess turbidity, color, odor, or taste -pathogens -dissolved toxins Importance of water management in preventing disease the microbial content of drinking water must be continuously monitored to ensure that water is free of infectious agents The most prominent water-borne pathogens include: *protozoans *bacteria *hepatitis A virus Enteric bacteria content of water is used to assess the level of fecal contamination *Coliforms are: -gram negative -enteric -lactose-fermenting -gas-producing bacteria *Enteric streptococci Water analysis *for testing level of bacteria in water *the number of colonies formed is used to estimate and differentiate the number of coliforms Coliform enumeration *it is used to determine the quality of coliforms in water by doing... -fecal coliform count (FCC) -fecal streptococcal count (FSC) *it can be done by the membrane filter method Water quality analysis *Using the membrane filter method -widely used rapid method that can be used in the field or in the lab to test larger quantities of water -after filtration, the membrane filter is placed in a Petri dish containing a selective medium -after incubation, coliform colonies can be counted and often presumptively identified by their distinctive characteristics on these media