chapter 20 - microbial ecosystems

Question 1

Ecosystem

Answer 1

sum of all organisms and abiotic properties

Question 2

Habitat

Answer 2

where community could reside in ecosystem

Question 3

Population

Answer 3

group of microorganisms of the same species

Question 4

Community

Answer 4

consists of populations living with other populations

Question 5

Microbial diversity

Answer 5

richness vs. abundance

Question 6

Species richness

Answer 6

total number of different species

Question 7

Species abundance

Answer 7

proportion of each species in an ecosystem

Question 8

Resources

Answer 8

carbon, nitrogen, oxygen

Question 9

Conditions

Answer 9

temperature, pH, O2 levels, light

Question 10

Guilds

Answer 10

metabolically related microbial populations

Question 11

Niche

Answer 11

habitat shared by a guild

Question 12

Biogeochemistry

Answer 12

study of biologically mediated chemical transformations

Question 13

Biochemical cycle

Answer 13

defines transformation of key element by biological/chemical agents

Question 14

Fundamental niche

Answer 14

full range of environmental conditions where organism can exist

Question 15

Prime/realized niche

Answer 15

each organism has at least one, where it is most successful

Question 16

Microenvironment

Answer 16

immediate environment surrounding of microbial cell
is always changing, hence wide range of conditions

Question 17

When can metabolic cooperation be seen?

Answer 17

when organisms carry out complementary metabolisms (syntrophy)

Question 18

Why are surfaces important for microbial habitats?

Answer 18

• offer great access to nutrients
• protection from predators
• offers cell to stay in favourable habitat, not get washed away

Question 19

Biofilms

Answer 19

• assemblage of bacterial cells on surface, in adhesive matrix
• helps trap nutrients for microbial growth

Question 20

What is the matrix made up of in biofilms?

Answer 20

mixture of polysaccharides

Question 21

What are the implications of biofilms?

Answer 21

1. self defense: resists antibodies
2. medical/dental conditions: kidney stones, strep, plaques on teeth
3. slow flow of liquids

Question 22

Microbial Mats

Answer 22

simply thick biofilms built by phototropic bacteria, containing filamentous cyanobacterias.

Question 23

Mineral soil

Answer 23

rock weathering and inorganic material

Question 24

Organic soil

Answer 24

sedimentation in bogs/marshes

Question 25

O Horizon

Answer 25

undecomposed plant material

Question 26

A Horizon

Answer 26

most microbial growth, rich organic mat with lots of nutrients

Question 27

B Horizon

Answer 27

little microbial activity, subsoil with a tad of nutrients from A horizon

Question 28

C Horizon

Answer 28

directly above bedrock

Question 29

What is the soil mainly composed of in microenvironment?

Answer 29

water and air: 50% inorganic matter: 40% organic matter: 5% micro/macroorganisms: 5%

Question 30

How is soil formed?

Answer 30

- CO2 formed by respiring organisms - freezing + thawing breaks apart rocks, allowing roots to penetrate

Question 31

Rhizosphere

Answer 31

area around plant roots where secrete sugars

Question 32

Arid soils

Answer 32

dry, limited plant growth in extreme temepratures, of low water and variable temperatures will slowly form

Question 33

Biological soil crust

Answer 33

made up of cyanobacteria use 16s rRNA gene sequencing to see phylogenetic samplings

Question 34

Terrestrial subsurfaces

Answer 34

lower than cell surface, grows in extremely nutrient-limited environments microbial diversity is seen in shallow subsurface areas

Question 35

Freshwater

Answer 35

highly variable in resources and conditions since photosynthesis and respiration work together to control O2 and CO2

Question 36

What are the oxygenic phototrophs in freshwater and what do they produce?

Answer 36

algae and cyanobacteria produce: oxygen and organic material

Question 37

Planktonic

Answer 37

free floating

Question 38

Benthic

Answer 38

attached to bottom or sides

Question 39

What depends on activity of primary producers?

Answer 39

heterotrophic microbes in aquatic systems

Question 40

Does water have limited solubility in water?

Answer 40

yes

Question 41

What are the three stratification of water columns in lake, what temperature do they have as well as oxygen and sulfur levels?

Answer 41

1. Epilimnion: warm, not dense, 24-20ºC, O2: 12-10mg/l, H2S: 0mg/l 2. Hypolimnion: cooler, dense, 8-4ºC, O2: 4-0mg/l, H2S: 6-5 mg/l 3. Thermocline: zone separating both, 20-8ºC, O2: 10-4mg/l, H2S: 0mg/l

Question 42

Biochemical oxygen demand

Answer 42

microbial oxygen consuming capacity (when NO3 goes up, cyanobacteria go up, they bring NO3 levels down)

Question 43

Phylogenetic sampling

Answer 43

16s rRNA gene sequencing

Question 44

What are the differences between marine and freshwater environments?

Answer 44

1. saline 2. low in nutrients 3. cooler 4. lower in microbial activity

Question 45

Oxygen minimum zone

Answer 45

regions where oxygen-depleted waters at intermediate depth

Question 46

Marine dead zone

Answer 46

a reduced level of oxygen in the water

Question 47

What is seen on top layer of ocean but not bottom?

Answer 47

Phototrophs and nutrients

Question 48

What is the major marine phototroph and what does it account for?

Answer 48

Prochlorococcus, accounts for >40% of biomass and 50% of net primary production.

Question 49

What happens to pelagic bacteria?

Answer 49

The deeper you go, bacteria levels will decrease, and archaea levels will rise, resulting in equal amounts of bacteria and archaea.

Question 50

Pelagibacter

Answer 50

Most abundant marine heterotroph

Question 51

Proteorhodopsin

Answer 51

captures light energy to drive ATP synthesis

Question 52

What is most abundant in pelagic marine

Answer 52

viruses, bacteriophages

Question 53

How must viruses/bacterias be in deep sea?

Answer 53

must be chemotrophic since there is low temp, and nutrient levels, and high pressure and no light

Question 54

How are deep sea sediments harvested?

Answer 54

by drilling ocean floor

Question 55

What are the two types of hydrothermal vents?

Answer 55

warm vents: cold water under, smoke less hot hot vents: extremely hot, black smoke

Question 56

What dominates in vents?

Answer 56

Chemolithotrophic bacteria as they use inorganic materials from vents (thermophiles and hyperthermophiles also present) more diversity in bacteria than archaea.