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BIO239 Microbiology And The Cycles Of Life > L10 Microbial Ecology and Elemental Cycling > Flashcards

L10 Microbial Ecology and Elemental Cycling Flashcards

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Biology 101 flashcards
1
Q

What are the 4 main cycles

A

Carbon
Nitrogen
Sulfur
Phosphorous

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2
Q

What drives the elemental cycles

A

Microbes

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3
Q

What are abiotic components contributing to elelmental cycles

A

Volcanic activity and fires
Weathering of rocks, sedimentation and run off
Gas absorption by oceans

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4
Q

What are biotic components contributing to elemental cycles

A

Photosynthesis and respiration
Elemental fixation for biomass
Environemtal mediation

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5
Q

What is environmental mediation

A

Altering the environment either as a consequence of microbial activity e.g. acidification in mine wastes or to alter the local conditions to better suit growth e.g. acidification by fungi, cabinate precipitation by biofilms

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6
Q

How can global warming impact microbial systems

A

accelerates methane release by methanogens

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7
Q

What was the role of microbes in early earth

A

Microbes created the atmosphere, built organic molecules of life and started the cycles

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8
Q

What is assimilation
Example

A

Process of acquiring an element and building biomass
Carbon fixation, absorption of glucose

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9
Q

What is dissimilation
Example

A

Breakdown of organic molecules into inorganic molecules
Respiration to carbon dioxide

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10
Q

What does metagenomics show us about a community

A

What species of microbes are oresent and how are they structured

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11
Q

What is the issue with metagenomics

A

Just because DNA is there it doesnt mean all the species there are active e.g. Spores

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12
Q

What does functional diversity tell us about a microbe community

A

Determine active processes
easure expressed genes for their function
Measure the products of metabolism

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13
Q

What is a limiting nutrient and what effect do they have on habitat colonisation

A

Habitat colonisation is regulated by limiting nutrients
The proportion of an available element that is low enough to control the growth - there is enough of all the elements to continue growth except for the limiting nutrient
Often not carbon

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14
Q

What is usually the limiting nutriwnt in aquatic systems

A

Nitrogen

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15
Q

What effect can addition of nitrogen have to aquatic systems
Give a location where this occurs

A

Algal blooms
Gulf of Mexico dead zone - run off from farming causes blooms which use up all the resources, heterotrophic bacter use up all the oxygen (hypoxia) so other species cannot survive

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16
Q

Abiotic environmental sources of nutrition (geomicrobiolgy)

A

Interaction with atmosphere, water and minerals
Autotrophy and lithotrophy

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17
Q

Biotic environmental sources of nurition (biogeochemistry)

A

Saprotrophy and symbiosis (mutualism, parasitism, pathogens, commenalism)
Heterotrophic and organotrophs

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18
Q

Give an example of when an elemnt may have high abundance but low availability

A

In forest systems where nitrogen is locked up in fungal cells
Marine systems with low soluble iron availability, most is stored in rocks

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19
Q

What parameters can affect microbial activity

A

Redox potential (dissolved salts)
Water availability and osmotic pressure
PH
Light
Limiting nutrients
Temperature
Oxygen
Toxic compounds
Interactions with other organisms

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20
Q

What is a source

A

Part of the biosphere that stores significant quantity of a particular element

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21
Q

What is a sink

A

Part of the biosphere that can recieve a particular element

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22
Q

What is a reservoir

A

Major parts of biosphere containing significant amount of a particular element (can be sources and sinks)

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23
Q

Examples of global carbon reservoirs

A

Atmosphere
Ocean (biomass, organic molecules, inorganic molecules)
Land (biomass, soil, crust, fossil fuel)

24
Q

What are 2 common pinciples of all priamry producers

A

Absorb energy from outside the ecosystem
Minerals assimilated into biomass

25
Q

What are the primary producers in terrestrial systems

A

Plants (and lichens in some habitats)

26
Q

What are the primary producers in aquatic environments

A

Cyanobacteria and algae (other photosynthetic eukaryotes e.g. Diatoms)

27
Q

What is edaphon

A

Living soil bacteria

28
Q

What is humus

A

Organic colloid, where organic compounds have reached a point of stability - also known as humic acid, water absorbant and good for plant rooting

29
Q

How much carbon dioxide is in the soil atmosphere compared to then the atmosphere

A

10 times more carbon dioxide

30
Q

What else can be found in the soil atmosphere

A

Transient gases (hydrogen, carbon monixide, methane, hydrogen sulfate) and volatile substances

31
Q

How much of the originally fixed carbon dioxide makes it to decomposers (fungi, bacteria) from consumers (protists, fungi)

A

10%

32
Q

How many species of fungi use nematodes to supplement their nutrition

A

160

33
Q

How do fungi trap nematode and recieve nutrition

A

Circular traps or glue traps (sticky fragments of mycelia)
Fungus penetrates and grows through nematode absorbing nutrition

34
Q

How can seasonal fluctuations affect wetland soil

A

Alter oxygen availability
Anaerobic / fermentation when flooded (hydric soil)
Aerobic when not

35
Q

Where is the littoral zone

A

Edge of water body

36
Q

What is the neuston

A

Air-water interface where a large number of microbes exist

37
Q

Where is the euphotic (photic) zone

A

Upper part of water column where light can penetrate for photoautotrophs

38
Q

Where is the aphotic zone

A

Fromt he end of the photic zone to the sediment

39
Q

How do algae and protists stay in the neuston

A

Use surface tension to ‘hang’ from surface

40
Q

What metabolic modes exist in the aphotic zone

A

Heterotrophs and lithotrophs

41
Q

What is the thermocline

A

Depth where temperature decreases steeply causing water density to increase

42
Q

What happens as water density increases
What metabolism peaks
How much organic matter is transferred to benthos

A

Organic matter settles into a stable unmixed region in the water column
Heterotroph populations peak
Low organic transfer to benthos

43
Q

What does oligotrophic mean when describing the open ocean

A

Extremely loe nutrient (iron and nitrogen) and organism concentration

44
Q

Do coastal waters have higher or lower nutrient content than open ocean

A

Higher

45
Q

What is BOD

A

Biological oxygen demand
How much oxygen is used in a given time period

46
Q

What happens if pollutants enter pelagic open water

A

Disruption of whole system, burst of heterotrophic activity

47
Q

How low does oxygen reach in open oceans

A

Can reach benthos for lithoautotrophs to use

48
Q

What is the oxygen minimum zone

A

Influx of nutrients - coastal currents lifting from below or input from pollution
Where organic molecules reach oxygen creating rapid heterotrophic proliferation
Region depleted of oxygen

49
Q

What can prolonged pollution cause

A

Dead zones

50
Q

What is the main difference between marine and freshwater environments

A

Salt content

51
Q

What are the layers of a freshwater lake

A

Neuston
Epilimnion
Thermocline
Hypolimmnion
Benthos / sediment

52
Q

What is the epilimnion

A

Warm, well-mixed oxygenated
Photo and heterotrophy

53
Q

What are the condition sin the hypolimnion and what survives here

A

Generally anoxic
Sulphur bacteria

54
Q

What are the conditions in the benthos of lakes and what microbes are present

A

Oxygen levels fall rapidly
Anaerobiv respirers

55
Q

What is the main pollutant of lakes

A

Nitrogen and phosphorous fertilisers

56
Q

What effect do fertilisers have on lakes (life cycle of bloom)

A

Remove limiting nutrients from algae causing a bloom
Blooms die, decomposed by heterotrophs which use up all the oxygen and release carbon dioxide
Creating anoxic environment

57
Q

How many more microbes are suppored in anoxic eutrophic lakes
What is the drawback

A

10 times more microbes - anaerobiv phototrophs, fermenters
Cannot suport much animal life

BIO239 Microbiology And The Cycles Of Life (12 decks)

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