Lecture 21

Question 1

Eutrophication

Answer 1

”is the process by which an entire body of water or parts of it, becomes progressively enriched with nutrients”

Question 2

The paradox of enrichment

Answer 2

Increasing the availability of resources (usually food) can lead to the decline or instability of a consumer’s population

Question 3

Components of paradox enrichment (4)

Answer 3

1. Increase resources
2. Consumer response
3. Overexploitation
4. Boom and bust
   Instability and/or extinction

Question 4

Green food web

Answer 4

• how producers obtain energy from primary production and
• how this energy moves up the food web when producers are consumed

Question 5

Brown food web

Answer 5

• how scavengers, detritivores, and decomposers obtain energy from dead organic matter
• how this energy moves up the food web when they are consumed

Question 6

Habitat coupling

Answer 6

“the linking of discrete habitats are connected through the movement and foraging of mobile consumers”

Question 7

Biogeochemical cycle

Answer 7

“the movement and transformation of chemical elements and compounds between living organisms and gaseous/solid/liquid forms in the atmosphere, and rocks, soils, and sediment”

Question 8

Pools

Answer 8

=> represent “the total amount of a particular substance or element within a specific compartment or reservoir in an ecosystem”
* Can include living organisms (plants, animals, and microorganisms) as well as non-living components (soil, water, and the atmosphere)
* Can vary greatly insize
* Can be relatively stable or dynmic
* Measurement units: mass (e.g., in kg)

Question 9

Examples of major pools

Answer 9

• Living biomass
• Detritus/organic matter/soil
  (soil organic matter, dissolved organic matter)
• Sediment
• Atmosphere
• Rocks

Question 10

Residence time

Answer 10

average amount of time energy or biomass remains within a specific compartment or trophic level
* Before it is either transferred to another pool or removed from the system altogether

Question 11

Equation of biomass residence time(years)

Answer 11

= total biomass in a pool (kg/m^3) / net biomass flux (kg/m^3/year)

Question 12

Evaporation

Answer 12

involves the conservation of liquid on the Earth’s surface into water vapor through the input of solar energy
- Primarily from the ocean surface but also from other water bodies

Question 13

Transpiration

Answer 13

release of water vapor from plants through small openings called stomata on their leaves
- Essentially the plant equivalent of evaporation
- Important component of the water cycle, particularly in terrestrial ecosystems

Question 14

Precipitation

Answer 14

Refers to the release of water from the atmosphere in the form of rain, snow, sleet, and hail

Question 15

Runoff

Answer 15

the movement of water over the land surface and into bodies of water such as rivers, lakes, and oceans.
- Occurs when precipitation exceeds the infiltration capacity of the soil or when the soil is saturated with water
- Transports water, sediment, and dissolved substances from one location to another

Question 16

Percolation/infiltration

Answer 16

the process by which water seeps into the soil downward through pores and fractures
- Replenishes soil moisture, recharges groundwater aquifers, and contributes to the storage of water in the subsurface

Question 17

Uptake

Answer 17

nutrients are taken up by organisms from the environment

Question 18

Decomposition

Answer 18

Dead organisms are broken down by decomposers

Question 19

Mineralization

Answer 19

the conversion of organic nutrients into inorganic forms that can e taken up by plants and other organisms

Question 20

Leaching

Answer 20

nutrients can be lost from ecosystems through leaching, where water carries dissolved nutrients downward through the soil layers

Question 21

Runoff

Answer 21

nutrients can be washed away from the lands surface into bodies of water

Question 22

Volatilization

Answer 22

nutrients are released into the atmosphere

Question 23

Weather

Answer 23

Physical/chemical breakdown of rocks

Question 24

Sedimentation

Answer 24

Movement of elements back into sediments

Question 25

Nitrogen fixation

Answer 25

the process by which atmospheric nitrogen gas (N2) is converted into ammonia (NH3) or other nitrogen-containing compounds
- Conversion of atmospheric nitrogen into a biologically usable form
- Nitrogen-fixing organisms (certain bacteria, archaea, and cyanobacteria) that possess the enzyme nitrogenase

Question 26

Nitrification

Answer 26

the biological oxidation of ammonia (NH3) to nitrite (NO2-) and then to nitrate (NO3-) by specialized bacteria called nitrifying bacteria
- Occurs primarily in aerobic (oxygen-rich) environments
- Nitrifying bacteria

Question 27

Ammonification

Answer 27

the microbial decomposition of organic nitrogen compounds (e.g., proteins, nucleic acids) into ammonia (NH3) and ammonium ions (NH4+).
- Releases nitrogen in the form of ammonium, making it available for uptake by plants and other organisms
- Carried out by various decomposer organisms, such as bacteria and fungi, during decomposition

Question 28

Denitrification

Answer 28

the reduction of nitrate (NO3-) and nitrite (NO2-) to nitrogen gas (N2) to nitrous oxide (N2O)
- Returns nitrogen gas to the atmosphere
- Denitrifying bacteria under the anaerobic (oxygen-deprived) conditions

Question 29

Weathering

Answer 29

the process by which phosphorus-containing minerals, such as apatite, are broken down by physical and chemical weathering processes, releasing phosphorus into the soil and water

Question 30

Stoichiometry

Answer 30

study of balance of elements and compounds in biological systems and their role in regulating ecological processes.
i.e. the elemental composition of organisms and ecosystems