Energy and Matter Fluxes

Question 1

differences between energy and matter supply to organisms

Answer 1

“energy is dissipated as heat and replaced by solar radiation - needs this ‘outside’ energy supply

matter is not lost, but is recyclable. However, it cannot be used by more than one organism at a time - needs decomposition to make matter available as nutrients”

Question 2

life-based energy fluxes

Answer 2

photosynthesis, albedo (from lack of vegetation)

Question 3

life-based matter fluxes

Answer 3

“hydrological cycle
carbon cycle
N, P, S cycling (global biogeochemical cycles)”

Question 4

what is GPP

Answer 4

gross primary productivity = total amount of glucose produced by photosynthesis in a given area

Question 5

what is NPP

Answer 5

“net primary productivity = GPP - glucose lost by respiration

the carbon that gets assimilated into the plant”

Question 6

basic explanation of carbon cycle

Answer 6

“photosynthesis, carbon intake as co2
carbon used to produce woody material in trees
carbon lost to soil
tree decomposes and releases co2 as it decomposes”

Question 7

traditional top down method of estimating GPP

Answer 7

eddy covariance/micrometeorological estimates - set up equipment above forest, measuring volume of co2 passing the sensor every second, take records over long time, average it for GPP

Question 8

biases of eddy covariance

Answer 8

co2 released by photosynthesis, which doesn’t happen at night, but respiration still does. Doesn’t measure this.

Question 9

traditional bottom up method of estimating GPP

Answer 9

take growth inventories to measure NPP and use chambers to measure co2 leaving (respiration) and add them together

Question 10

how are satellites now used to estimate GPP

Answer 10

“photosynthesis energy absorbance causes a small fluorescence that satellites can measure on large scales

or measure greenness of plants - amount of chlorophyll to estimate production”

Question 11

how is NPP estimated

Answer 11

inventory, empirical model simulation, biogeochemical model simulation, dynamic global vegetation model simulation remote sensing estimation

Question 12

how is inventory used to estimate global NPP

Answer 12

combine observation data from each biome

Question 13

how do empirical models simulate estimates of global NPP

Answer 13

correlate field NPP data with environmental parameters such as rainfall or temperature

Question 14

how do biogeochemical models simulate estimates of global NPP

Answer 14

create ecosystem-scale carbon cycle models

Question 15

how do dynamic global vegetation models simulate estimates of global NPP

Answer 15

ecosystem scale vegetation structure change and carbon cycle models

Question 16

how does remote sensing estimate global NPP

Answer 16

senses absorbed solar radiation, and uses it to solve for NPP

Question 17

why is NPP increasing globally

Answer 17

“we use more fertilizer, so more nitrogen

more co2 in the air

longer growing seasons bc climate change”

Question 18

how much global NPP is appropriated by humans

Answer 18

25%

Question 19

what are the most productive ecosystems

Answer 19

tropical rainforests, estuaries, swamps and marshes

Question 20

why is there more matter in a forest than its productivity

Answer 20

some NPP is fixed as wood, which stays there for as long as the tree s alive

Question 21

where is soil carbon highest globally

Answer 21

temperate areas, where colder temperatures slow the decomposition processes, slowing its release as co2, sometimes storing it as peat

Question 22

what is a detritivore

Answer 22

organism that breaks detritus into smaller pieces e.g. worm

Question 23

what is a decomposer

Answer 23

organism that uses enzymes to break detritus into simple inorganic substances e.g. certain bacteria or fungi

Question 24

3 factors effecting amount of energy transferred from one trophic level to the next

Answer 24

consumption efficiency, assimilation efficiency, production efficiency

Question 25

what is consumption efficiency

Answer 25

% of NPP of one trophic level consumed by the next trophic level, e.g. herbivores eat 5% of a forests NPP, while carnivores eat 50-100% of vertebrate prey NPP

Question 26

what is assimilation efficiency

Answer 26

% of energy from consumed food that is available to the organism

Question 27

what is the assimilation efficiency of different trophic levels

Answer 27

20-50% for herbivores, 80% for carnivores, 100% for bacterial decomposers

Question 28

what is production efficiency

Answer 28

% of assimilated energy that is converted into new biomass

Question 29

3 ways to compare the trophic levels in an environment

Answer 29

“energy that passes through them

biomass of the biological material

number of organisms”

Question 30

anthropogenic perturbation of nitrogen cycle

Answer 30

nitrogen fixed in soil by farming of leguminous plants, and humans fixing N from air into fertilizer, combustion

Question 31

anthropogenic perturbation of phosphorus cycle

Answer 31

mining phosphate rocks for industrial purposes, fertilizer, animal feed etc

Question 32

anthropogenic perturbation of sulphur cycle

Answer 32

fossil fuel burning, ore smelting, acid rain, dry deposition from atmosphere

Question 33

factors considered in atmospheric co2 projections

Answer 33

“fossil fuel emissions
land-use co2 emissions
response of oceans and terrestrial biosphere”