11 - Water Microbiology Flashcards
(74 cards)
1
Q
Aquatic primary producers
A
Photoautotrophs, phytoplankton
- Algae
- Cyanobacteria
2
Q
What do the biological activities of an aquatic ecosystem depend on?
A
The activities of primary producers for :
- food for other otganisms
3
Q
What eats primary producers
A
Chemoautotrophs:
- bacteria
- protozoa
- zooplankton
- fish
- other aquatic animals
4
Q
Activities of phytoplankton depend on :
A
- Temperature
- Light received
- Nutrient availability : nitrogen, phosphorus
5
Q
Photic zone
A
zone of water that receives sunlight:
deepest 300m in clear water
6
Q
Accessory pigments
A
help microorganism harvest light at great water depths
7
Q
Halotolerants
A
organism that can survive high salinity environments ( 3%)
8
Q
Pelagic zone
A
Open ocean: little nutrients : N, P little primary production - Oligotrophic - 75% of the ocean
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
10
Q
Primary PRODUCERS in open ocean
A
Mostly prochlorophytes
11
Q
Procholococcus
A
a prochlorophyte:
- tiny phototrophs
- phylogenetically related to cyanobacteria
- bulk of primary production in open ocean
12
Q
Microorganic adaptation in pelagic zones:
A
- reduced size -> high surface area/volume ratio
- high affinity transport systems
13
Q
Trichodesmium
A
- filamentous cyanobacteria
- contains phycobilins
- nitrogen fixer
14
Q
Coastal waters
A
High primary production: influx of nutrients from rivers and polluted water sources (nitrogen, phosphorus)
Eutrophic
15
Q
Red tides
A
Algal bloom : dinoflagellates, neurotoxins
Limited by nitrogen
16
Q
Costal waters primary producers
A
Algae
Cyanobacteria
Supports higher concentration of zooplankton and aquatic animals
17
Q
Deep sea 300-1000m
A
Chemoheterotrophs degrade organic material that falls from photic zones
- 2-3C
- Psychrophiles (cold water)
18
Q
Deep sea bellow 1000m
A
Organic carbon is very scarce
- No light
- Oligotrophic
- very few microorganisms : psychrophilic& barophilic or barotolerant (high pressure)
19
Q
Hydrothermal vents
A
Source of : - Heat - Nutrients - Eletron donors &acceptors creates communoty of microorganisms and animals
20
Q
Tube worms
A
Symbiosis with sulfur oxidizing chemoautotrophs
Tube worms trap and transport nutrients to bacteria
21
Q
Freshwater Environment
A
Highly variable
Microbial activity depending on nutrient availability
22
Q
fresh water microorganism activity depends on :
A
Nutrient, oxigen and light availability
Limited by : nitrogen and phosphorus
23
Q
Lakes (general)
A
Poor mixing/aeration
can be eutrophic or oligotrophic
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)
25
Oligotrophic Lakes
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
26
Eutrophic Lake
Primary production is high -> availability of organic matter is high
Rapid growth of chemoheterotrophs -> rapid depletion of oxygen -> anaerobic zones created
Poor light penetration
27
Health risks of eutrophic lakes
Pathogens
| Cyanobacterial/algae blooms (secrete toxins)
28
Eutrophic lakes : Bottom sediments
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
29
Eutrophic Lakes: H2S and organic acids
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
30
Summer stratification
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
Epilimnion
lake stratification : top layer
- warmer
- less dense
- aerobic
32
Thermocline
lake stratification : middle layer
| Zone of rapid temperature change
33
Hypolimnion
Lake stratification : bottom layer
- more dense
- colder
- anaerobic
34
Pollution of fresh waters
- deliberate discharge of effluents into a waterway
| - mostly sewage
35
Sewage pollution of water
- sewage is rich in organic materials and contains many microorganism
- high chance of containing pathogens
- BOD is high
36
Biochemical Oxygen Demand
[BOD]
| - used as a measure of the extent of organic matter pollution
37
High BOD
Water tends to be anaerobic
| Microbial metabolisms : fermentation, sulfate reduction, nitrate reduction ...
38
Biofilms
```
microbial cells (mixed species) embedded inside an extracellular matrix.
Extracellular matrix: proteins, polysaccharides, DNA
Cells inside biofilms are more resistant to stresses
```
39
Water-borne pathogens
Most from intestinal tracks -> contamination comes from fecal matter
Sources of infection :
- contaminated drinking water
- recreational water
40
Salmonella typhi
```
Water-borne pathogen
Causes:
- Typhoid fever in humans
- systemic infection
Healthy carriers
```
41
Vibrio cholerae
Water-borne pathogen
Causes:
- Cholera
- severe diarrhea (enterotoxin: affecting the digestive tract)
42
Shigella spp.
Water-borne pathogen
Causes:
- shigellosis
- bacterial dysentery (bloody diarrhea, inflamation of the intestinal mucosa)
43
Salmonella spp.
Water-borne pathogen other than typhi
Causes:
- salmonellosis
- gastroenteritis
44
gastroenteritis
- inflammation of the stomach and intestines causing diarrhea and vomiting
45
Campylobacteria spp.
Water-borne pathogen
Causes:
- gastroenteritis (most common cause in canada)
46
Enterovirus
Water-borne virus
- poliovirus
- norovirus
- rotavirus (children)
47
Hepatitis A
water-borne virus
48
Entamoeba histolytica
Water-borne pathogenic protozoa
| - amoebic dysentery (intestinal infection)
49
Gardia lamblia
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
Cryptosporidium parvum
```
Water-borne pathogenic protozoa
Causes:
- chronic and acute diarrhea
Self limiting in healthy individuals-> major problems in immunocompromised individuals.
No reliable treatment
```
51
Transmission of C. parvum and G. lamblia
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
Water quality control
Impossible to test for all organism-> test for common fecal microorganisms
Most water-borne pathogens are associated with fecal material
53
Water quality indicators:
Coliforms
Fecal coliforms
Presences of these (E.coli especially) indicated fecal contamination
Absence does not ensure purity (cysts)
54
Coliforms
- 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
Fecal coliforms
coliforms derived from the intestines of warm blooded animals
- thermotolerant (44.5C)
56
Most Probable Number
MPN
Presumptive test for coliforms:
- sample is added to lactose broth -> gas production indicates positive test
57
Membrane filtration
Tests for coliforms and fecal coliforms
- test large volume of water
- faster and easier than MPN
58
Water treatment aims:
- removes pathogens
- improves clarity of water
- removes compounds that cause bad smell & taste
Extent of treatment depends on water origins
59
Steps in water treatment
```
1- Sedimentation
2- Coagulation
3- Filtration
4- Disinfection
5- Storage & distribution
```
60
Sedimentation
Water is left to stand in a reservoir/sedimentation basin
| - allows large particles(sands) to settle
61
Coagulation/ Flocculation
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
Filtration
- 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
Disinsection
```
Using chlorine (chlorination) or ozone
Ozone: is more effective than chlorine but much shorter half-life
Water is now safe for human consumption
```
64
Chlorination
- chlorine is very active in water -> forms a strong oxidizing agent
- kills remaining microorganisms (some are resistant)
- neutralizes chemicals causing bad taste & odor
65
Residual chlorine
amount of chlorine that remains in the water that has left the treatment plant .
needed to protect the distribution system
66
Wastewater treatment: aims and steps
```
(sewage treatment)
Aims:
- reduce BOD
- destroy pathogens
Steps :
- Primary treatment
- Secondary treatment
- Tertiary treatment
```
67
Primary treatment
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
Secondary treatment
uses microorganisms to reduce BOD and bacterial concentrations further
- Trickling filter
- Activated sludge
69
Trickling filter
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
Activated sludge
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
Secondary treatment : Sludge
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
Tertiary treatment
```
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
Final liquid affluent
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
Septic tank
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
