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Introductory Microbiology > Water > Flashcards

Water Flashcards

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Biology 101 flashcards
1
Q

The biological activity of an aquatic ecosystem ultimately depends on

A

The activities of the primary producers (phytoplankton)

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2
Q

What are primary producers in the ocean

A

Algae

Cyanobacteria

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3
Q

Phytoplankton serve as ___ for chemeheterotrophs

A

A food source

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4
Q

The activities and net number of phytoplankton and net numbers of phytoplankton depend on

A
  • Temperature
  • Light received
  • Availability of specific limiting nutrients such as nitrogen and phosphorus
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5
Q

What is photic zone

A

In clear water, light will penetrate to a maximum of 300 m

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6
Q

How deep the light penetrates in coastal waters

A

50 m

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7
Q

Why in open ocean there is more light penetration than in the coastal region

A

Near the coat there is more particles dissolved

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8
Q

What organisms live in the ocean and why ( salt)

A

High salinity (3%)-> halotolerant or hylophylic

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9
Q

What is pelagic zone

A

the water column of the open ocean, and can be further divided into regions by depth. . It goes from the surface almost to the bottom

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10
Q

75 % of the ocean is deeper than

A

1000 m

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11
Q

What is the pressure at the deepest place in the ocean

A

1100 atm

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12
Q

What is the correlation between the depth and the pressure

A

every 10 m increasing by 1 atm

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13
Q

Below 100 m the temperature of the ocean is constant

A

2-3C

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14
Q

The open ocean is ___ (low nutrients)

A

oligotrophic

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15
Q

What is the outcome of the fact that the open ocean is oligotrophic

A

primary productivity is very low due to the lack of inorganic nutrients ( nitrogen, phosphorus, iron) that are required byp hytoplankton

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16
Q

Temperature of the water is ___ closer tot he shore

A

Warmer

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17
Q

What happens in some regions due to wind and ocean currents

A

Upwelling of water from the ocean floor bringing nutrients to the surface and promoting productivity

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18
Q

What is an indicator of the primary productivity

A

Chlorophyll

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19
Q

Chlorophyll concentration depends on

A

The season

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20
Q

bulk of primary productivity comes from

A

prochlorophytes

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21
Q

What are procholorophytes and there latin name

A

Tiny phototrophs phylogenetically related to the cyanobacteria.

Prochlorococcus

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22
Q

General adaptations seen in pelagic (open ocean) microorganisms

A
  • Reduced size (high surface//volume ration)

- High affinity transport system

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23
Q

Who are trichodesmium and there characteristics

A
  • Filamentous cyanobacteria
  • Contains phycobilins ( help to capture light)
  • Nitrogen fixation
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24
Q

As the primary productivity is higher in coastal water, how it can be called

A

Eutrophic

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25
Q

Where the influx of nutrients coming from to costal waters

A

Influx of nutrients from rivers and other polluted water sources (agricultural runoff= excess nitrogen, phosphorus)

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26
Q

There can be red tides near the coastal region caused by

A

Ceratium (dinoflagellate)

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27
Q

What is the limiting nutrient in red tides

A

Nitrogen

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28
Q

A higher level of primary productivity supports a higher concentration of ___

A

Zooplankton and aquatic animals

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29
Q

What is marine snow

A

As plants and animals near the surface of the ocean die and decay, they fall toward the seafloor, just like leaves and decaying material fall onto a forest floor. In addition to dead animals and plants, marine snow also includes fecal matter, sand, soot, and other inorganic dust.

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30
Q

explain marine carbon pump

A

The carbonate pump starts with marine organisms at the ocean’s surface producing calcium carbonate This CaCO3 is what forms hard body parts like shells.The formation of these shells increases atmospheric CO2

Particulate organic carbon, created through biological production, can be exported from the upper ocean in a flux commonly termed the biological pump

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31
Q

What happens in the ocean between 300 and 1000 m

A

Chemoheterotrophs degrade organic matter that falls from the photic zone

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32
Q

What are the conditions and who live in the area 300 to 1000 m

A

2-3C

Psychrophiles

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33
Q

What happens below 1000 m and who live there

A

Organic matter is scarce, oligotrophic, no light. Very few microorganisms ( psychrophylic and barophylic or barotolerant)

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34
Q

What organisms was found at 5000 m deep

A

Xenophyophore- large protist

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35
Q

Hydrothermal vent is a source of

A

Heat, nutrients, electron donors, electron acceptors

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36
Q

What are tube worms

A

Symbiosis with sulfur oxidizing chemoautotrophs. Tube worms trap and transport nutrients to the bacterial symbionts

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37
Q

Lake is more ___ compared to the ocean

A

Highly variable

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38
Q

Microbial populations in the lake depend on

A

The availability of nutrients, and the availability of light and oxygen. Limited by the availability of nitrogen and phosphorus

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39
Q

Mixing and aeration in lakes and rivers

A

Lakes (poor mixing/ aeration)

Rivers (good mixing/ aeration)

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40
Q

What are oligotrophic lakes

A

N and P are limiting

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41
Q

What are conditions in oligotrophic lakes

A

Growth of aerobic chemoheterotrophs is limited by nutrient supply; oxygen concentration remains high: Rate of oxygen dissolution is higher than the consumption rate

Oxygen saturated

Lake remains aerobic even at depth and organic matter is degraded completely

Clear water (deep penetration of light)

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42
Q

Example of an oligotrophic lake

A

Lake in the mountains

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43
Q

Eutrophic lake is

A

nutrient rich

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44
Q

Describe eutrophic lake

A

Primary production is high (algal bloom), availability of organic matter is high

Rapid growth of chemoheterotrophs, rapid depletion of dissolved oxygen

Low oxygen

Anaerobic zones are created

Poor light penetration

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45
Q

What are health risks in eutrophic lakes

A

Pathogens, bloom of cyanobacteria/algae (secrete toxins)

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46
Q

Example of eytrophic lake

A

a pound, blooming lake

47
Q

What happens at the bottom sediments in eutrophic lake

A

They are anaerobic and contain organic matter (dead primary producers) which support growth of denitrifiers, methanogens and sulfate reducers (H2S)

48
Q

What eutrophic anaerobic organism use for photosynthesis

A

Uses H2S as electron do not and produces sulfate, which is used by sulfate reducers

49
Q

What gives a bad odor to the lake

A

Excessive production of organic acids from fermentation

50
Q

What is bad in eutrophic lake for animals

A

The lack of oxygen and/or presence of H2S may kill fish and other aerobic organisms

51
Q

What can happen as a result of summer stratification

A

Anaerobic zones get created

52
Q

What is epilimnion and how it get formed

A

As the air temperature increases, the surface water is warmed resulting in the formation of a warm upper layer-epiliminion- less dense, aerobic

53
Q

What is hypolimnion

A

The colder, bottom layer, denser anaerobic - is seperated from the epilimnion by a zone of rapid temperature change

54
Q

What is the name of the zone of rapid temperature change between epilimnion and hypolimnion

A

thermocline

55
Q

In what seasons the lake has thermocline

A

Summer and winter

56
Q

What happens in spring and fall with the water in lake

A

It does have zones , it is circulating
In spring-> 4 C
In fall-> 10C

The mixing brings the nutrient back up the water column

57
Q

What is the result of good mixing. aeration in rivers

A

Ensures that organic matter, within limits, is degraded effectively ( no fermentation, no H2S production)

58
Q

Excess organic matter in rivers can result in

A

Anaerobic areas with consequences similar to those in eutrophic lakes

59
Q

What is pollution of freshwater

A

Deliberate discharge of effluents into a waterway-> major source is sewage

60
Q

Characterize sewage water

A

It is rich in organic matter and contains a large number of organisms (some may be pathogens)

61
Q

What is BOD

A

Biochemical oxygen demand-- it is used ti measure the extent of pollution by organic matter.

62
Q

In polluted water is there a lot of oxygen

A

Water tends to become anaerobic, microbial metabolism: fermentation, sulfate reduction, nitrate reduction

63
Q

What is the biofilm

A

Microbial cells embedded inside an extracellular matrix. usually produced by a mixed population of species

64
Q

Explain the structure of biofilm

A

Extracellular matrix composed of proteins , polysaccharides, DNA

65
Q

What is the advantage of the biofilm than an individual cell

A

Cells inside the biofilm are more resistant to stresses that planktonic (free-living cells)

66
Q

Where biofilms are found

A

In water systems( natural and man-made), on wet surfaces, growing on medical devices, etc.

67
Q

Water borne pathogens are coming from

A

They grow in the intestinal tract and transmission is mediated by fecal contamination of water supplies

68
Q

Sources of water infection

A
  • Potable water (drinking and food preparation)

- Recreational water (swimming)

69
Q

7 water-borne bacterial pathogens and viruses

A
  • Salmonella typhi
  • Vibrio cholerae
  • Shigella spp
  • Salmonella spp
  • Campylobacter spp
  • Enterovirus:norovirus, rotavirus
  • Hepatitis A virus
70
Q

Salmonella typhi causes

A

Typhoid fever in humans, systematic infection, healthy carriers

71
Q

Vibrio cholerae causes

A

cholera, severe diarrhea (enterotoxin)

72
Q

Shigella spp causes

A

Shigellosis; bacterial dysentery (bloody diarrhea, inflammation of the intestinal mucosa)

73
Q

Salmonella spp ( other than typhi) causes

A

Salmonellosis

Gastroenteritis

74
Q

Campylobacter spp causes

A

Gastroenteritis, most common cause of gastroenteritis in Canada

75
Q

The name of the organisms that cause amoebic dysentery

A

Entamoeba histolytica

76
Q

What does Giardia lamblia cause

A

Giardiasis (backpacker’s disease/beaver fever), chronic diarrhea,

77
Q

How can you get Giardia lamblia

A

often associated with drinking water in wilderness areas ( beavers and muskrats are frequent carriers- source of contamination of streams)

78
Q

What does Crystosporidium parvum cause

A

Chronic and acute diarrhea. Is not a problem for healthy individuals, but a major problem for immunosuppressed individuals

79
Q

Crystosporidium parvum the presence in sewage and river waters

A 
In sewage (90%)
75% in rover water
80
Q

What are the problems with cysts of Crystosporidium parvum and Giardia lamblia

A

resistant to a number of disonfectants, including chlorine

C.parvum cysts are not effectively removed by filtratin process in water-plants, because they are too small

81
Q

Most water-borne pathogens are associated with

A

Fecal material

82
Q

How the water quality is assessed

A

Test for organisms that are present in large amounts in feces. If these organisms are there, there is a chance that the water may also contain pathogens

83
Q

Two indicators of water quality

A
  • Coliforms

- Fecal coliforms

84
Q

What are coliforms

A

Includes a variety of bacteria not all of intestinal origin. Facultative aerobic, Gram-negative, non spore-forming, rod shaped that can ferment lactose with gas formation within 48 hours at 35 C.

85
Q

What are fecal coliforms

A

Coliforms derived from the intestines of warm-blooded animals (can grow at 44.5C, thermotolerant)

86
Q

What is the organism that serves as an indicator of fecal contamination

A

The presence of fecal coliforms, especially E.coli

87
Q

Why the absence of fecal coliforms does not ensure goof water quality

A

Cysts are more resistant than fecal coliforms

88
Q

What is MPN

A

Most probable number

Test for coliforms: samples are added to lactose broth, If gas production is detected, test is positive

Then the tables are used to estimate the MPN of coliforms in the original sample

89
Q

Describe membrane filtration test

A

Test for coliforms and fecal coliforms
Can test large volume of water (100 ml)
Faster and easier than MPN

90
Q

Eosin-methylene blue medium is selective and deferential for

A

Lactose-fermenting bacteria

91
Q

What are the aims for water treatment

A
  • Remove pathogens
  • Improve clarity of water
  • Remove compounds that give bad smell or taste
  • Soften the water
92
Q

Steps in water treatment

A

1) Sedimentation
2) Flocculation treatment
3) Filtration
4) Disinfection

93
Q

Describe what happens during sedimentation step

A
  • Water is left to stand in a reservoir

- Allow large particle (sand) to settle

94
Q

Describe what happens during flocculation treatment step

A
  • Coagulant is added
  • Water is transferred to a flocculation basin and allowed to settle for 6 hours
  • As the flocs(flaky participates) form, they trap fine particles (clay, bacteria, viruses, protists)
  • Some organic chemicals are also absorbed by the flocs
95
Q

How much bacteria are removed during flocculation treatment

A

around 80% of bacteria , color and particles

96
Q

What is happening in filtration step

A

The water is filtered through sand to remove remaining particles, even more bacteria and any remaining G. lamblia cysts

97
Q

How many bacteria is removed after filtration

A

98-99.5%

98
Q

What is done with filtration to avoid clogging

A

Backflushed

99
Q

What is done during disinfection step

A

CHLORINATION->Chlorine is very reactive in water, it forms strong oxidizing agents. It kills remaining microorganisms, neutralizes most of the chemicals that give water a bad smell/taste

100
Q

What is residual chlorine

A

Amount of chlorine that remains in the water leaving the treatment plant. Desired/ required to protect the distribution system

101
Q

Ozone is more effective that chlorine ( kills G.lamblia and C.parvum cysts). Why it is not so widespread?

A

Very short half-life

102
Q

What is the threshold for safe water for humans

A

Less than 10 coliforms /100 ml

less than 1 fecal coliform/ 100 ml

103
Q

What are the ais for wastewater( sewage) treatment

A
  • Reduce BOD(remove/ destroy organic matter)

- Destroy pathogens

104
Q

What happens during primary treatment of sewage water

A

Sedimentation tanks: 40-70% of suspended solids settle. Produces primary sludge (Dried and incinerated or secondary treatment).

105
Q

Primary treatment reduces the BOD to__ and bacteria by ___

A

BOD to 25-40%

Bacteria by 25-75%

106
Q

What happens after primary treatment

A

Wastewaters can be discharged to waterways or go though secondary treatment: use microorganisms to reduce the BOD and the concentration of bacteria further

107
Q

What is trickling filter, how it reduces BOD and bacteria

A

Liquid from primary treatment that is sprayed over a bed of rock or plastic honeycomb. Microorganisms form biofilms, coating the surface and oxidize the organic matter present in the sewage. BOD reduced by 80-95%, bacteria by 90-95%

108
Q

What is activated sludge, how it reduces BOD and bacteria

A

Air is blown through the liquid from primary treatment. Slime -forming bacteria grow and clump together to form flocs (activated sludge) that oxidize the organic matter. Then , the material passes to a settling tank, sludge is removed for disposal or secondary treatment. BOD reduced by 85-95%, bacteria by 90-98%

109
Q

What happens after the sludge is created

A

The primary and secondary sludge, containing cellulose and other organic compounds, is subjected to microbial digestion under anaerobic conditions. CH4 produced can be used to power the treatment plant. BOD reduced by 90%. Material that remains is incinerated or buried.

110
Q

What is tertiary treatment

A

May involve

  • Biological treatment( ponds: algae)
  • Flocculation
  • Filtration
  • Chlorination or ozonation
111
Q

How can the final liquid effluent be used

A

It comes after all 3 treatments and may be suitable for drinking (coliforms and fecal coliforms below limits)

112
Q

What is septic tank

A

-minimal treatment of sewage
-Within the tank: settling of the material and minimal sludge digestion- requires periodic emptying
BOD reduced by 60%

113
Q

What does the leaching to the fields do with the water from the sepric tank

A

The water still have a lot of coliforms. It reduces amount of water in the tank. Soils act as a filter and organisms decompose organic matter. BUT careful not to contaminate groundwater and nearby waterways

Introductory Microbiology (21 decks)

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