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Microbiology - LSCI 230 > 11 - Water Microbiology > Flashcards

11 - Water Microbiology Flashcards

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Biology 101 flashcards
1
Q

Aquatic primary producers

A

Photoautotrophs, phytoplankton

  • Algae
  • Cyanobacteria
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2
Q

What do the biological activities of an aquatic ecosystem depend on?

A

The activities of primary producers for :

- food for other otganisms

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3
Q

What eats primary producers

A

Chemoautotrophs:

  • bacteria
  • protozoa
  • zooplankton
  • fish
  • other aquatic animals
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4
Q

Activities of phytoplankton depend on :

A
  • Temperature
  • Light received
  • Nutrient availability : nitrogen, phosphorus
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5
Q

Photic zone

A

zone of water that receives sunlight:

deepest 300m in clear water

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6
Q

Accessory pigments

A

help microorganism harvest light at great water depths

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7
Q

Halotolerants

A

organism that can survive high salinity environments ( 3%)

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8
Q

Pelagic zone

A 
Open ocean:
little nutrients : N, P 
little primary production 
- Oligotrophic 
- 75% of the ocean
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9
Q

Primary production in pelagic zone

A

Primary production is low : Lack of inorganic nutrients ( nitrogen, phosphorus, iron)
-> Oligotrophic
Winds and currents can cause nutrient upwelling promoting burst of productivity

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10
Q

Primary PRODUCERS in open ocean

A

Mostly prochlorophytes

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11
Q

Procholococcus

A

a prochlorophyte:

  • tiny phototrophs
  • phylogenetically related to cyanobacteria
  • bulk of primary production in open ocean
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12
Q

Microorganic adaptation in pelagic zones:

A
  • reduced size -> high surface area/volume ratio

- high affinity transport systems

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13
Q

Trichodesmium

A
  • filamentous cyanobacteria
  • contains phycobilins
  • nitrogen fixer
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14
Q

Coastal waters

A

High primary production: influx of nutrients from rivers and polluted water sources (nitrogen, phosphorus)
Eutrophic

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15
Q

Red tides

A

Algal bloom : dinoflagellates, neurotoxins

Limited by nitrogen

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16
Q

Costal waters primary producers

A

Algae
Cyanobacteria
Supports higher concentration of zooplankton and aquatic animals

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17
Q

Deep sea 300-1000m

A

Chemoheterotrophs degrade organic material that falls from photic zones

  • 2-3C
  • Psychrophiles (cold water)
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18
Q

Deep sea bellow 1000m

A

Organic carbon is very scarce

  • No light
  • Oligotrophic
  • very few microorganisms : psychrophilic& barophilic or barotolerant (high pressure)
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19
Q

Hydrothermal vents

A 
Source of : 
- Heat 
- Nutrients 
- Eletron donors &acceptors 
creates communoty of microorganisms and animals
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20
Q

Tube worms

A

Symbiosis with sulfur oxidizing chemoautotrophs

Tube worms trap and transport nutrients to bacteria

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21
Q

Freshwater Environment

A

Highly variable

Microbial activity depending on nutrient availability

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22
Q

fresh water microorganism activity depends on :

A

Nutrient, oxigen and light availability

Limited by : nitrogen and phosphorus

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23
Q

Lakes (general)

A

Poor mixing/aeration

can be eutrophic or oligotrophic

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24
Q

Rivers

A

Good mixing/aeration
-> ensures (within limits) degradation of organic matter
- no fermentation
- no H2S production
Excess organic matter -> anaerobiosis (no fish or other aerobic organisms)

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25
Q

Oligotrophic Lakes

A

Nitrogen and phosphorus are limiting
Oxygen supply is high -> lake remains aerobic even at higher depths
organic mater is degraded completely.
clear water -> deep light penetration
Primary production is low, availability of organic matter is low

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26
Q

Eutrophic Lake

A

Primary production is high -> availability of organic matter is high
Rapid growth of chemoheterotrophs -> rapid depletion of oxygen -> anaerobic zones created
Poor light penetration

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27
Q

Health risks of eutrophic lakes

A

Pathogens

Cyanobacterial/algae blooms (secrete toxins)

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28
Q

Eutrophic lakes : Bottom sediments

A

Anaerobic and contain organic matter :
Supports the growth of denitrifiers methanogens and sulfate reducers
Anaerobic photosynthesis: uses H2S as electron donor and produces sulfate-> used by sulfate reducers

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29
Q

Eutrophic Lakes: H2S and organic acids

A

Excessive H2S production from anaerobic photosynthesis and organic acids from fermentation :

  • gives water bad odour
  • with lack of oxygen -> kills fish and other aerobic organisms
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30
Q

Summer stratification

A

Separation of the lake into zones determined by temperature
- may develop anaerobic zones -> lake becomes thermally stratified
Water mixing, in the spring and fall only, bring nutrients from the bottom to the top

31
Q

Epilimnion

A

lake stratification : top layer

  • warmer
  • less dense
  • aerobic
32
Q

Thermocline

A

lake stratification : middle layer

Zone of rapid temperature change

33
Q

Hypolimnion

A

Lake stratification : bottom layer

  • more dense
  • colder
  • anaerobic
34
Q

Pollution of fresh waters

A
  • deliberate discharge of effluents into a waterway

- mostly sewage

35
Q

Sewage pollution of water

A
  • sewage is rich in organic materials and contains many microorganism
  • high chance of containing pathogens
  • BOD is high
36
Q

Biochemical Oxygen Demand

A

[BOD]

- used as a measure of the extent of organic matter pollution

37
Q

High BOD

A

Water tends to be anaerobic

Microbial metabolisms : fermentation, sulfate reduction, nitrate reduction …

38
Q

Biofilms

A 
microbial cells (mixed species) embedded inside an extracellular matrix. 
Extracellular matrix: proteins, polysaccharides, DNA 
Cells inside biofilms are more resistant to stresses
39
Q

Water-borne pathogens

A

Most from intestinal tracks -> contamination comes from fecal matter
Sources of infection :
- contaminated drinking water
- recreational water

40
Q

Salmonella typhi

A 
Water-borne pathogen
Causes:
- Typhoid fever in humans 
- systemic infection
Healthy carriers
41
Q

Vibrio cholerae

A

Water-borne pathogen
Causes:
- Cholera
- severe diarrhea (enterotoxin: affecting the digestive tract)

42
Q

Shigella spp.

A

Water-borne pathogen
Causes:
- shigellosis
- bacterial dysentery (bloody diarrhea, inflamation of the intestinal mucosa)

43
Q

Salmonella spp.

A

Water-borne pathogen other than typhi
Causes:
- salmonellosis
- gastroenteritis

44
Q

gastroenteritis

A
  • inflammation of the stomach and intestines causing diarrhea and vomiting
45
Q

Campylobacteria spp.

A

Water-borne pathogen
Causes:
- gastroenteritis (most common cause in canada)

46
Q

Enterovirus

A

Water-borne virus

  • poliovirus
  • norovirus
  • rotavirus (children)
47
Q

Hepatitis A

A

water-borne virus

48
Q

Entamoeba histolytica

A

Water-borne pathogenic protozoa

- amoebic dysentery (intestinal infection)

49
Q

Gardia lamblia

A

Water-borne pathogenic protozoa
Causes:
- giardiasis (backpacker’s disease/beaver fever)
- chronic diarrhea
Often associated with drinking water in the wilderness often carried by local animal life

50
Q

Cryptosporidium parvum

A 
Water-borne pathogenic protozoa 
Causes: 
- chronic and acute diarrhea
Self limiting in healthy individuals-> major problems in immunocompromised individuals.
No reliable treatment
51
Q

Transmission of C. parvum and G. lamblia

A

Both form cysts which are resistant to most disinfectants: including chlorine
C. parvum cysts are not effectively removed by water filtration: present in 28% of drinking water samples

52
Q

Water quality control

A

Impossible to test for all organism-> test for common fecal microorganisms
Most water-borne pathogens are associated with fecal material

53
Q

Water quality indicators:

A

Coliforms
Fecal coliforms
Presences of these (E.coli especially) indicated fecal contamination
Absence does not ensure purity (cysts)

54
Q

Coliforms

A
  • facultative aerobic
  • gram negative
  • non spore forming
  • rod shaped
  • can ferment lactose -> with gas formation
    Includes a variety of bacteria not with fecal origins
55
Q

Fecal coliforms

A

coliforms derived from the intestines of warm blooded animals
- thermotolerant (44.5C)

56
Q

Most Probable Number

A

MPN
Presumptive test for coliforms:
- sample is added to lactose broth -> gas production indicates positive test

57
Q

Membrane filtration

A

Tests for coliforms and fecal coliforms

  • test large volume of water
  • faster and easier than MPN
58
Q

Water treatment aims:

A
  • removes pathogens
  • improves clarity of water
  • removes compounds that cause bad smell & taste
    Extent of treatment depends on water origins
59
Q

Steps in water treatment

A 
1- Sedimentation 
2- Coagulation 
3- Filtration 
4- Disinfection  
5- Storage & distribution
60
Q

Sedimentation

A

Water is left to stand in a reservoir/sedimentation basin

- allows large particles(sands) to settle

61
Q

Coagulation/ Flocculation

A

Chemical coagulation treatment
- a flocculating chemical (coagulant) is added
- water is transferred to a flocculation basin and allowed to settle
- as the flocs form, they trap fine particles (clay, bacteria, protists&some organic chemicals)
Removes +- 80% of bacteria, colour and particulates

62
Q

Filtration

A
  • water is filtered throuhg sand -> removes remaining particles and G. lamblia cysts
    After this 98-99.5% of bacteria have been removed
    Filter is backflushed regularly-> prevents clogging
63
Q

Disinsection

A 
Using chlorine (chlorination) or ozone 
Ozone: is more effective than chlorine but much shorter half-life 
Water is now safe for human consumption
64
Q

Chlorination

A
  • chlorine is very active in water -> forms a strong oxidizing agent
  • kills remaining microorganisms (some are resistant)
  • neutralizes chemicals causing bad taste & odor
65
Q

Residual chlorine

A

amount of chlorine that remains in the water that has left the treatment plant .
needed to protect the distribution system

66
Q

Wastewater treatment: aims and steps

A 
(sewage treatment)
Aims: 
- reduce BOD 
- destroy pathogens 
Steps :
- Primary treatment 
- Secondary treatment 
- Tertiary treatment
67
Q

Primary treatment

A

Sedimentation tanks: 40-70% of suspended solids settle. Flocculating chemicals can be added.
Produces: primary sludge
Reduction :
BOD: 25-40%
Bacteria:25-75%
–> discharged to waterways or secondary treatment

68
Q

Secondary treatment

A

uses microorganisms to reduce BOD and bacterial concentrations further

  • Trickling filter
  • Activated sludge
69
Q

Trickling filter

A

Liquid from primary treatment is sprayed over either a bed of rocks or plastic honeycomb.->microorganism form a biofilm coating rocks/honeycomb -> oxidizes organic matter
Reduction:
BOD:80-95%
Bacteria:90-95%

70
Q

Activated sludge

A

air is blown through liquid from primary treatment.
Slime-forming bacteria grow and clump -> form flocs (activated sludge) -> oxidizes organic matter
Next material passes through a settling tank, sludge is removed for disposal or secondary treatment
Reduction:
BOD:85-95%
Bacteria:90-98%

71
Q

Secondary treatment : Sludge

A

Primary and secondary sludge contains:
- Cellulose
- other organic compounds
is subject to microbial digestion under anaerobic conditions -> produces:
- CH4 which can be used as an energy source for the treatment plant
- remaining material is incinerated or buried
Reduction:
BOD: 90%

72
Q

Tertiary treatment

A 
Further reduces BOD, bacteria, nitrogen and phosphorus concentrations 
May involve any combination of: 
- biological treatment (ponds: algae) 
- Flocculation
- Filtration
- Chlorination/Ozonation
Produces : Final liquid affluent
73
Q

Final liquid affluent

A

waste water that has gone through primary, secondary, and tertiary treatment
Maybe suitable for human consumption if coliform and fecal coliform levels are bellow limits

74
Q

Septic tank

A

Minimal waste water treatment
Settling of the material and minimal sludge digestion-> effluent flows to a leaching field: soil acts as a filter organisms decompose organic matter
possibility of groundwater and nearby water way contamination
Tank require regular emptying

Microbiology - LSCI 230 (4 decks)

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