Terrestrial environment

Question 1

soil

Answer 1

Loose outer material of earth’s surace

Question 2

Soil layers

Answer 2

O horizon
A horizon
B horizon
C horizon

Question 3

O horizon

Answer 3

At the surface, composed of undecomposed plant material

Question 4

A horizon

Answer 4

Most M growth, rich in organic material and nutrients
Plant roots release nutrients in exchange for ecosystem function

Question 5

B horizon

Answer 5

subsoil where organic material leached from A gather, little M activity

Question 6

C horizon

Answer 6

base that is directly above bedrock and forms from bedrock
No O2 and all microbes strictly chemolithotrophs

Question 7

Soil groups

Answer 7

Mineral soil
organic soil

Question 8

Mineral soil

Answer 8

Derived from rock weatherig and other inorganic material

Question 9

Organic soil

Answer 9

Derived from sedimentation in bogs and marshes

Question 10

soil composition

Answer 10

40% inorganic mineral
5% organic matter
50% air and water
5% M and macro organisms

Question 11

Soil formation

Answer 11

Formed by interdependant physical, chemical and biological processes
-CO2 is formed by respiring organisms that form Carbonic acid that breaks down rock
-Physical processes such as freezing and thawing break apart rocks, allowing plant roots to penetrate and form an expanded rhizosphere

Question 12

Rhizosphere

Answer 12

Area around plant roots where plants secrete sugars and other compounds, is rich in organic matter and microbial life

Question 13

water availibility

Answer 13

It is variable and dependant on rainfall, plant coverage, drainage and soil composition

Question 14

Soil solution

Answer 14

Soil water has many dissolved materials

Question 15

soil and water

Answer 15

Well-drained soils have O2 availibility while waterlogged soils are typically anoxic, with O2 being consumed by soil M

Question 16

Arid soils

Answer 16

They are dry, have limited plant growth and are home to M communities specialised for extreme conditions
-Arid soils lose more moisture from evapotranspiration than gained from precipitation
-Make 35% of land mass and are extreme environments with low water availibility and varied temp ( below -24 and above 60)

Question 17

BSC

Answer 17

Biological soil crusts are made of photosynthetic cyanobacteria and filamentous fungi that stabilise soil

Question 18

BSC and arid

Answer 18

Arid soils are very slow to form and are subject to desertification, where BSC is damaged and soil fertility is decreased

Question 19

Phylogenetic sampling

Answer 19

Molecular sampling indicates thousands of different M species

Question 20

Phylotype

Answer 20

A species defined by a 16S rRNA sequence that differs from all other sequences by 3%
M diversity varies with soil type and geological location

Question 21

Red well

Answer 21

Due to M that convert Fe3+ in soil to Fe2+ that goes into water

Question 22

Most limiting nutrients

Answer 22

Nitrogen
Phosphorous

Question 23

Polluted soil

Answer 23

-Undisturbed, unpolluted soils support very high Pro diversity
-soil perturbations trigger measurable shifts in community composition toward species that are more competitive
-Polluted soils reduce richness and increase species abundance

Question 24

Climate and disturbance effects on soil M

Answer 24

Microbial diversity in any environment is a dynamic entity and will change-sometimes dramatically- in response to environmental changes in conditions and resources

Question 24

Soil subsurface

Answer 24

-extend for sevral hundred meters below soil surface
-Archae and B exist here in variable concentrations depending on nutrient availibility
-Usually grows in extremely nutrient limited environment
-small cells common

Question 25

Deep subsurface

Answer 25

Home to a group of organisms that may be Archae and are related to Eu, the lokiarcheota
-Generation time can be days, years or centuries depending on nutrients

Question 26

Determine microbe diversity

Answer 26

-Suspend soil in sterile liquid and then shake and let settle
-Use DNA extraction kit
-Use 16S ALAnine primers to amplify and then sequence DNA
-Use sequence to determine phylotype of soil M
-If % similarity is lower than 97% of reference genome, it may belong to a new species
-If species can’t be determined than full genome sequencing must be done to discover new species