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Environmental Microbiology University of Regina > Water Environments > Flashcards

Water Environments Flashcards

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1
Q

How much of the earth is water? Fresh water?

A
  1. 8%

0. 4%

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2
Q

How much of the primary production on earth is aquatic?

A

50%

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3
Q

Where is the nutrient rich part of the ocean?

A

Costal

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4
Q

Why are there salty lakes in prairies?

A
  • Net water deficit in summer

- H2O comes in and carries salts in- evaporates and leaves salts behind

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5
Q

Why are there water stressors in Canada?

A

Lakes not good location, decreased rain, increased population

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6
Q

What are 3 zones of lakes?

A
  1. Littoral Zone-Photic; near shore; primary production high at sediments
  2. Pelagic Zone- photic; open water
  3. Profundal Zone- Aphotic; Water and sediment below oxygen = consumed
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7
Q

What’s the pelagic zones 3 regions?

A
  1. Epilimnion
  2. Thermocline
  3. Hypolimnion
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8
Q

What are oxygen concentrations in aquatic systems are dependent on?

A

The amount of organic matter present and the physical mixing of the system

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9
Q

Whats stratification in summer? What happens in the fall?

A
  • Based on heat exchange
  • Temp barrier preventing cold deep water from mixing with top hot water
  • In the fall cooling of the top where it’s the same temp as bottom uses mixing of lake= no stratification
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10
Q

Why is water at 4 degrees most dense?

A

It floats

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11
Q

What happens to the lakes temperature in the winter?

A
  • Ice forms- can’t diffuse O2
  • Traps O2 under ice
  • Temp decreases which slows aerobic respiration which decreases O2 usage
  • Will become anoxic
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12
Q

What are the different light zones of a lake?

A

Photo zone: 0-200 m allows light penetration and photosynthesis
Aphotic zone: No light, ∴ heterotrophic activity
Turbid waters:
Light penetration < 1m

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13
Q

What does ability of light penetrating O2 depend on?

A

Depth and particles

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14
Q

Why are there only the colour blue in deep ocean water?

A

Because only blue wavelengths can penetrate that deep

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15
Q

Coastal and Ocean Waters, compared to most freshwater environments, the open ocean environment is?

A

• Saline
• Low in nutrients, especially with respect to nitrogen,
phosphorus, and iron
• Cooler

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16
Q

What are major factors in earths C balance?

A

Microbial activities in oceans

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17
Q

Where is there more microbes in the ocean?

A

Shore because of higher nutrients

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18
Q

What are the 5 zones of an ocean?

A
  1. Photic zone
  2. Benthic zone
  3. Pelagic Zone
  4. Aphotic zone
  5. Nertic zone
  6. Intertidal zone
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19
Q

3 areas of the pelagic zone in the ocean

A
  1. Mesopelagic
  2. Bathypelagic
  3. Abyssopelagic
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20
Q

What tropies are lakes, wetlands and oceans?

A

lakes are oligotrophic (nutrient poor), wetlands eutrophic (well nourished), oceans both depending on location

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21
Q

What are upwelling zones?

A
  • Bring cold, nutrient rich water up from depth

- Mixing of oceans

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22
Q

What does red represent in the picture on page 15 lecture 5?

A

Chlorophyll levels

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23
Q

What is phytoplankton? Bacterioplankton?

A
  • Phytoplankton-eukaryotic (algae) and prokaryotic (cyanobacteria)- harmful toxins
  • Bacterioplankton- bacteria that don’t have to be attached to anything
24
Q

What are 4 plankton habitats?

A
  • phytoplankton
  • bacterioplankton
  • viruses
  • zooplankton (incl. protozoan)
25
Q

Why is sampling the pelagic zone easier than soils?

A
  • more homogeneous
  • less site-to-site variation
  • can use pumps and lines
  • known volumes and depths can be sampled
  • less destructive
26
Q

Why is sampling bacteria in water hard?

A
  • processing difficult due to low numbers of MOs

* generally use filtration- hard to catch on filter

27
Q

What does primary production depend on? How much is done in oceans? Where does it happen?

A
  • Nutrients
  • 50%
  • nutrients (N and P), Temp, turbidity (light), Fe
  • happens mainly in areas of upwelling, and coastal areas
28
Q

What is most of the primary productivity in the open oceans is due to? How much O2 is it responsible for? Describe the organism

A
  • photosynthesis by prochlorophytes
  • 20-50% O2
  • Non motile
  • Most plentiful org on earth
29
Q

What biomass does Protochlorocuccus account for? How much net primary production?

A
  • > 40% biomass of marine phototrophs

- 50%

30
Q

What do harmful algal blooms occur from? Result?

A
  • Phytoplankton toxins
  • often occur in upwelling and high nutrient areas
  • kill marine life and are harmful to us
31
Q

How much of the C fixed by primary producers is released back into water? Used by what?

A
  • More than half

- Bacterioplankton

32
Q

Whats the microbial loop? Slide 38 Lecture 5

A
  • Phytoplankton releases C to DOM (excrete and lysis) and zooplankton graze on them
  • Bacterioplankton uptake DOM and are lysed DOM; also release (mineralization) CO2 which phytoplankton uptake
  • Zooplankton excrete DOM and grase on bactivorous zooplankton and phytoplankton
  • Bacteria production (utilization of DOM) available to the secondary production
33
Q

Whats POM and DOM?

A
  • POM – particulate organic matter – large macromolecules that make up structural components of cells
  • DOM – dissolved organic matter – smaller soluble material that passes through a 0.7um filter
34
Q

How much small planktonic heterotrophic prokaryotes are in pelagic marine waters?

A

abundant (10^5–10^6 cells/ml)

35
Q

How much microbes in surf water vs deep?

A

Surface waters contain ~106 cells/ml; cell numbers drop to 10^3–10^5/ml below 1,000 m in depth

36
Q

Whats the most abundant marine bacteria? Why?

A
  • Pelagibacter ubique
  • Streamlined genome reduces the amount of energy required for cell replication
  • Saves energy by using the A and T (≈70.3% of all base pairs) because they contain less N
37
Q

What are the most abundant microbes in the ocean with the most genetic diversity? How much? What does it influence?

A
  • Viruses
  • 10^30 viruses in the ocean
  • influence the composition of marine communities and are a major force behind biogeochemical cycles
  • Selection
  • Major source of mortality and disease in marine orgs
38
Q

What takes up the most biomass or abundance in an ocean?

A

Biomass- Prokaryotes

Abundance- Virueses

39
Q

Whats a viral shunt? Benefit?

A

-Moves material from heterotrophs and photoautotrophs into POM and DOM
-chemical composition of the POM and DOM are not the same as the orgs the
material came from
-Makes POM and DOM accessible to orgs

40
Q

What are benthic habitats? Characteristics?

A

• transition zone between water and mineral subsurface • diffuse and noncompacted mixtures of OrganicMatter, mineral
material, and water
• nutrient rich – MO activity and diversity is v. high
-Similar to soil except water on top

41
Q

How much slower does O2 diffuse in water than air? Why is it easily depleted by heterotrophs?

A

10^4

By anaerobic organisms

42
Q

How to sample benthic zone?

A

Cores- Keep samples intact

  • Can study over time
  • Good way
43
Q

What does that amount of mercury depend on?

A

amount of gram negative sulfate-reducing bacteria (SRB)

44
Q

Whats Desulfovibrio

A
  • gram negative sulfate-reducing bacteria (SRB)
  • commonly found in aquatic environments with high levels of OM
  • growth may be limited in aerobic environs, they can survive in presence of O2 (aerotolerant)
45
Q

How is inorganic Hg methylated to MeHg? What does the amount of MeHg depend on? What is MeHg?

A
  • By Sulphate reducing bacteria
  • Depends in part on the activity of the SRB, as well as Hg available
  • MeHg is a neurotoxin that gets into fish
  • SRB mediated MeHg production is NB b/c this is the main source of MeHg in aquatic systems
46
Q

What are biofilms? What do they do?

A

• Surface association of MOs attached by an extracellular polymer matrix

•Assemblages of bacterial cells adhered to a surface and
enclosed in an adhesive matrix excreted by the cells
•The matrix is typically a mixture of polysaccharides

•Biofilms trap nutrients for microbial growth and help prevent detachment of cells in flowing systems

47
Q

Why are surfaces important microbial habitats?

A
  • Nutrients adsorb to surfaces

* Microbial cells can attach to surfaces

48
Q

Why do bacteria form biofilms?

A
  • Self-defense
  • Biofilms resist physical forces that sweep away unattached cells, phagocytosis by immune system cells, and penetration of toxins (e.g., antibiotics)
  • Allows cells to remain in a favorable niche
  • Allows bacterial cells to live in close association with one another
49
Q

How much antimicrobial does it take to get rid of biofilms?

A

~1000 times more antibiotic dose to eliminate bacteria attached to a surface in a biofilm compared to normal free-living bacteria

50
Q

How to sample biofilms?

A
  • difficult to sample b/c associations btwn MOs and substrate can be strong
  • can scrape, very invasive
  • artificial substrates are useful
  • microelectrodes are often used
51
Q

What type of bacteria are abundant in biofilms?

A

Extremophiles

52
Q

Whats a microbial mat? Built by what bacteria?

A
  • interfacial aquatic habitat – multi-layered sheet of micro- organisms, mainly bacteria and archaea.
    -Very thick biofilms
  • phototrophic at some point
  • can exist on land
  • usually held together by
    slimy substances secreted by MOs
    -phototrophic and/or chemolithotrophic bacteria
53
Q

How long have cyanobacteria mats been in ecosystems?

A

3.5 billion years

54
Q

What are stromatolites?

A
  • built up of layers of lime-secreting cyanobacteria and trapped sediment
  • Very old
  • 6-10 cm thick
  • Slow growing
  • Oldest fossils
55
Q

Whats at West Chaplin Lake

A

A microbial mat

Environmental Microbiology University of Regina (10 decks)

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