4: Environmental Microbiology Flashcards
We can think of soil as a “_______”
biological fire
a gaseous product of microbes that gives soil its musty odor
geosmin
microbial pathogen in soil, which can cause botulism, tetanus, and gas gangrene
clostridium
gram positive bacillus or “box cars” found in soil that forms endospores and hates oxygen. causes gas gangrene (amputation is only treatment)
clostridium perfringens
microbes are essential for the recycling of certain chemical elements so that they can be reused
biogeochemcial cycle
What “fixes” CO2 into organic compounds?
green plants, algae, and bacteria
Why is nitrogen needed by all organisms?
for the synthesis of proteins, nucleic acids, and other nitrogen-containing compounds
Free nitrogen gas makes up _____ of the atmosphere
80%
What do microbes fix atmospheric nitrogen and nitrogen in organic matter into?
ammonia (NH3) gas
Ammonia is further processed by microbes into _____ which are directly used by plants for _____.
nitrates (NO3-), protein synthesis
formed a symbiotic relationship with roots of leguminous plants. the bacteria causes roots for form nodules where the bacteria thrive. What does the bacteria do in return for the plant?
Rhizobium fixates nitrogen into ammonia, to be converted to nitrates for use by the plant
The fixation of nitrogen gas by microbes is accomplished by what microbial enzyme?
nitrogenase
combination of fungus and an alga, or a cyanobacterium in a mutualistic relationship
lichens
most dangerous form of water pollution
fecal contamination
responsible for over 2 million deaths (globally) each year, mostly among children under 5 yrs.
waterborne diseases
most important criterion is that it is consistently in human feces in substantial numbers so that its detection is a good indication that human wastes are entering the water
indicator organism
usual indicator organisms for water purity tests
coliform bacteria
predominant fecal coliform
escherichia coli
direct method of determining the presence and numbers of coliforms and is probably the most widely used method in North America and Europe (water purity test)
membrane filtration method
5 Steps of Water Treatment
standing in reservoir, flocculation, surface absorption, chlorination, and storage reservoirs
During water treatment, what is the purpose of water standing for a period of time in a reservoir?
allows large particulate matter to settle out