Lecture 27 - Environmental Microbiology Flashcards
What is the imporance of “crusts”?
crusts can help hold soil in place which prevents erosion + stabilizes soil enough for water to get in and allow some plants to grow
How many bacteria can be found in 1 g of soil?
100 million - 1 billion
The center of a compost pile is ____.
Hot
(up to 60 C)
Streptomyces is an important source of _______.
antibiotics
How can camels find water from so far away?
They can smell the chemicals produced by streptomyces.
gangrene
soft tissue death
ischemia
inadquate blood supply
Clostridium perfringens can cause _____.
Gangrene
Biogeochemcial Cycles
how elements are cycled between living and non-living parts of the biosphere
How is CO2 in the air used?
used by plants, algae and cyanobacteria for photosynthesis to make sugar and water
Fixation of CO2
CO2 is fixated into sugars in the tissues of plants, algae and cyanobacteria
Plants and Animals both release CO2 back into the air through what process?
Cellular Respiration
Decomposition of dead plants and animals release ____ into the air.
CO2
Is CO2 dissolved in water for use by aquatic life?
yes
Burning wood and fossil fuesl releases ____ into the air.
CO2
What is the most abundant molecule in the air?
Nitrogen (N2)
Fixation of Nitrogen
N2 is fixated to NH3
N2
free nitrogen gas
NH3
ammonia
Nitrification
NH3 is converted into NO2- then NO3-
NO2-
Nitrite
NO3-
Nitrate
Denitrification
Nitrate (NO3-) is converted back into free nitrogen gas (N2)
Legumes and Rhizobium are important for ______.
Nitrogen Fixation
Non-Symbiotic Fixating Microbes
microbes which can fixate nitrogen, but live freely in the soil
Symbiotic Fixating Microbes
microbes which can fixate nitrogen and live inside of plant roots (i.e. Rhizobium & Bradyrhizobium live in the roots of legumes)
Xenobiotics
synthetic chemicals not readily degraded by microbes
bioremediation
the breakdown and elimination of environmental contaminants by living organisms
3 Variables Influencing Bioremediation
- Temperature
- Amount of O2 available
- Concentration of Potentially Limiting Nutrients
Biostimulation
the addition of nutrients to a contaminated site to stimulate the microbes doing the bioremediation
Bioaugmentation
the use of pollutant-acclimated microbes or GMOs for bioremediation
GMO
genetically modified organisms
aeration
mixing air into water
coagulation and flocculation
removes large numbers of viruses and bacteria in water by adding aluminum sulfide which will coagulate and cause clumps which will then settle to the bottom of the tank and leave cleaner water at the top
List the Step of Treating Water
Water from a reservoir is aerated then moved into a mixing chamber.
Aluminum Sulfide is added to the the water for coagulation and flocculation where the larger, coagulated particles will settle to the bottom of a settling tank, leaving clearer water on top. The water on top is then filtered.
Membrane Filtration of Water can Effiectively Eliminate
Giardia and Cryptosporidium
3 Methods to Disinfect Water
- Chlorine
- UV Light
- Ozone Treatment
BOD
Biochemical Oxygen Demand
Biochemical Oxygen Demand Test
measures the amount of organic waste in water by measuring the amount of oxygen that has been used over the course of 5 days
Eutrophication
water pollution from fertilizers/sewage may encourage algal blooms at the expense of animal life
How is sewar water treated?
- Large contaminants (sludge) are removed from sedimentation tanks
- Primary effulent undergoes oxidation and then is cycled through a settling tank a couple of times
- Water is filtered to form secondary effluent
- Water is disinfected then released
Trickling Filter
sewage water is sprayed over zoogleal biofilm-covered rocks which oxidize the organic material in the water
Rotating Biological Contactor
Massive Disks Covered in Zoogleal Biofilm rotate through water to oxidze the organic material
How is Sludge Digested?
Anaerobic microorganisms are added to break down the slude. Methane is released in the process.
Explain How Septic Tank Systems Work
Water goes from the house to the septic tank. Solids settle out. Effluent flows out of the septic thank into a leeching field where microbes in the soil can degrade organic material in the effluent.
Puprose of Tertiary Water Treatment
follows disinfection to remove remaining BOD, N, and P.
What happens to a retired landfill?
It is converted into a bioreactor to speed up the rate of decomposition of materials by about 30%.
