soil food web

Question 1

what can be contained in a handful of healthy soil

Answer 1

billions of individual bacteria, several km of fungal hyphae, up to 100,000 protists, up to 500 beneficial nematodes, micro-arthropods(mites and springtails)

Question 2

what are soil organisms

Answer 2

a multitude of different species found in the soil that range in size, where they live in the soil (habitat), and what they do in the soil (their function)

they are related through the soil food web

Question 3

what is the definition of the soil food web

Answer 3

a complex community of organisms living all or part of their lives within the soil, which interact through the transfer of energy, nutrients, and carbon between species within the ecosystem

the soil food web describes how these different organisms interact, specifically how nutrients, energy, and carbon are exchanged

Question 4

what is a trophic level

Answer 4

a group of organisms within an ecosystem that occupy the same level in the food web

Question 5

what is in the first trophic level

Answer 5

photosynthesizers

Question 6

what do photosynthesizers do

Answer 6

they capture carbon from the atmosphere and energy from the sun

Question 7

what is in the second trophic level

Answer 7

decomposers, mutualists, pathogens, parasites, root feeders

Question 8

whats in the third trophic level

Answer 8

shredders, predators, grazers

Question 9

whats in the fourth trophic level

Answer 9

higher-level predators

Question 10

whats in the fifth and higher trophic levels

Answer 10

higher-level predators

Question 11

what fuels the food web and what captures the energy

Answer 11

photosynthesis and primary producers (such as plants, algae, moss) use the suns energy to fix CO2 from the atmosphere

Question 12

where do organisms higher on the trophic levels get their energy and carbon from

Answer 12

by consuming the organic compounds found in primary producers, waste by-products, and other organisms in the food web

Question 13

what happens as different organisms comprising the soil food web consume other organisms

Answer 13

energy is exchanged between trophic levels and nutrients are exchanged between organisms or released into the inorganic environment (soil solution or the atmosphere)

Question 14

what depends on the activity of the soil food web

Answer 14

nutrient cycling and thus plant growth

Question 15

within the food web, organisms can be categorized on the basis of…

Answer 15

Where they get there source of carbon (heterotrophs or autotrophs)

Where they get there source of energy (phototrophs or chemotrophic)

Question 16

what are autotrophs

Answer 16

organisms that obtain their cellular carbon from CO2

Question 17

what are heterotrophs

Answer 17

organisms that obtain their carbon from pre-formed organic compounds and are incapable of using inorganic compounds as sole sources of energy

Question 18

what are phototrophs

Answer 18

organisms that obtain their energy from the sun

Question 19

what are chemotrophs

Answer 19

organisms that get their energy from biochemical oxidation of inorganic elements such as N, S, and from organic energy sources such as carbohydrates, lipids, and proteins

Question 20

what is an example of a chemoheterotrophs

Answer 20

all animals, fungi, actinobacteria, and most bacterial

Question 21

what is an example of photoheterotrophs

Answer 21

a few algae

Question 22

what is an example of chemoautotrophs

Answer 22

ammonia oxidizers, sulfur oxidizers

Question 23

what is bacteria

Answer 23

single-cell organisms, prokaryotic, can be both auto and heterotrophic, most abundant group of soil microorganisms

Question 24

what role do bacteria play on the soil

Answer 24

important for: nutrient cycling, soil organic matter formation, remediation of contaminated soils, and a variety of symbiotic interactions with plants and other soil microbes

Question 25

what is fungi

Answer 25

heterotrophic organisms, ranging from microscopic single-cell yeast to multicellular filamentous organisms

Question 26

what is the function of fungi

Answer 26

primarily responsible for decomposition of complex macromolecules (ex. lignin) comprising organic matter

fungi are generally more abundant than bacteria in forest soils (due to lignin)

Question 27

what are the benefits of fungi

Answer 27

help to cycle nutrients and carbon, and form soil organic matter

form filamentous hyphae, which is good for foraging for food and is important for stabilizing soil aggregates

can also have a symbiotic relationship with plants ex. myerrhizal

Question 28

how can fungi be bad

Answer 28

can be pathogenic and cause diseases in planta, animals, and humans

produces spores prolifically, therefore, can be easily dispersed in the environment (many are airborne)

soil type, pH, water content, and temperature affect the presence of soil-borne plant pathogenic fungi

Question 29

what are protists

Answer 29

single-cell eukaryotes, many are predatiors-consume other microorganisms, some cause plant disease,

Question 30

what is clubroot and how can we reduce the spread

Answer 30

it is a soil-born disease caused by a protist pathogen affection canola in Canada

to reduce we can make sure to clean equipment when moving field and have a diverse crop rotation

Question 31

what are algae and cyanobacteria

Answer 31

photosynthetic organisms that can fix C via photosynthesis, therefore, they must be at or near the soil surface.

some cyanobacteria can also fix atmospheric N2

together they are important colonizers in early soil formation and they can add both organic C and N to parent materials (ie. primary producers)