Chapter 21: Energy Flow Through Ecosystems Flashcards
(71 cards)
1
Q
Whats an ecosystem?
A
- inseparable link between biotic environment (community) and abiotic environment
2
Q
Ecosystem ecology focuses on what?
A
- the exchange of energy and mater within ecosystem and inputs and outputs to and from environment
3
Q
What are some beneficial ecosystem services?
A
- purification of air and water
- mitigation of droughts and floods
- generation and preservation of soils and soil fertility
- detoxification and decomposition of wastes
- pollination of crops and vegetation; seed dispersal
- nutrient cycling
- control of agricultural pests by nature enemies
- maintenance of biodiversity
- protection of coastal shores from erosion
- protection from ultraviolet rays
- partial stabilization of climate
- moderation of weather extremes
4
Q
Why are ecosystem services undervalued in society?
A
- no dollar sign attached to make you halla honey booboo
5
Q
Examples of the undervaluing of ecosystem services?
A
- NYC water supply from catskill mountains degraded by sewage, fertilizer and pesticides
- invested 1-1.5 billion dollars to buy land around catchment area to restrict use and subsidized construction of better sewage treatment plants
- cheaper than 6-8 billion dollars to build and operate a water filtration plant
6
Q
What is the ultimate source of energy in almost all ecosystems ?
A
- sunlight
- used in photosynthesis
7
Q
Sunlight energy is stored in?
A
- chemical bonds of carbohydrates and other carbon compounds after PS
- source of energy of other organisms
8
Q
Energy is the capacity to?
A
DO WERK
9
Q
What are the two laws of thermodynamics we covered ?
A
fuck if I know.
- Conservation of energy: energy may be transferred from one form to another but it is neither created nor destroyed
- When energy is transferred or transformed, part of the energy assumes a form that can do no further work
10
Q
Example of the first law of thermodynamics?
A
- wood is burned, potential energy lost = kinetic energy released as heat
11
Q
Example of the second law of thermodynamics?
A
- part of energy transferred to another organism is stored in living tissue, but large part dissipated as heat
12
Q
Potential energy?
A
- stored energy. Capable of and available for performing work
13
Q
Kinetic energy?
A
- energy in motion
14
Q
What is primary production?
A
- rate of conversion of radiant energy (sunlight0 to organic compounds by photosynthesis
15
Q
What is gross primary production (GPP)?
A
- total photosynthesis
16
Q
Some of the energy produced by plants is used for?
A
- respiration (R), reproduction and growth
17
Q
What is net primary reproduction (NPP)?
A
- rate of energy storage as organic matter
18
Q
What is the formula for net primary reproduction?
A
- GPP-R=NPP
19
Q
Explain the example for estimating NPP in aquatic systems?
A
- two bottles of phytoplankton
- one is exposed to light
- one is not
- the bottle exposed to light will allow us to see how much O2 is produced by PS and how much is consumed in respiration (NPP)
- dark bottle allows us to just see O2 consumed n respiration (R)
- if you subtract the two = O2 produced by photosynthesis (GPP)
20
Q
Rates of productivity are expressed as?
A
- given time period (year) and per unit area (kilocalories/m^2/year)
21
Q
Net primary production accumulates over time as?
A
-plant biomass
22
Q
Standing crop biomass is expressed as?
A
- grams of organic matter m^-2 or kcal m^-2
23
Q
Specifically define biomass! (wiki version)
A
Biomass, in ecology, is the mass of living biological organisms in a given area or ecosystem at a given time
24
Q
In terrestrial ecosystems productivity is affected by?
A
- climate
- increases with painful and temperature!
25
With respect to global map of terrestrial productivity what is the pattern seen?
- productivity is highest in coastline, tropical and moist areas.
- no productivity in areas that there is a lack of water (dessert and arctic) and lack of light (arctic)
26
Does the availability of nutrients also affect NPP?
- yep
| - as nitrogen mineralization (kg/ha/yr)for example, increases so does ANPP(Mg/ha/yr)
27
What are limiting factors of NPP?
- light, water(moisture, temperature, nutrients, nitrogen cycling
* * they will stop/lower productivity if lacking
28
Rank the continental (terrestrial) ecosystems in order of greatest NPP to lowest!
- tropical rain forest
- tropical seasonal forest
- temperate evergreen forest
- temperate deciduous forest
- boreal forest
- savanna
- cultivated land
- woodland and shrubland
- temperate grassland
- tundra and alpine meadow
- desert shrub
- rock, ice and sand
- swamp and marsh
- lake and stream
29
Rank the marine (aquatic) ecosystems in order of greatest NPP to lowest!
- algal beds and reefs
- estuaries
- upwelling zones
- continental shelf
- open ocean
30
Why is there such an interest in studying tropical rainforests?
- they have high NPP
31
Comparisons of ecosystems:
| - there are how many orders of magnitude variation in primary productivity?
- 3
| * * 200, 20, 2000
32
Comparisons of ecosystems:
| - What is the area coverage of Deserts and tundra in the world and their productivity?
- 17%
- 2.2%
* *huge areas but contribute very little
33
Comparisons of ecosystems:
| - What is the area coverage of tropical rainforests in the world and their productivity?
- 16.4%
| - 42.3%
34
Comparisons of ecosystems:
| - What is the area coverage of open ocean in the marine area and their productivity?
- 92% of marine area
- 76% production
* *most of the ocean is not very productive but its sheer size is what contributes to it
35
Comparisons of ecosystems:
| - What is the area coverage of algal beds, reefs and estuaries in the world and their productivity?
- ~ 0.55%
| - ~6.3 of marine production
36
Are high productivity areas generally threatened?
- YEP
| - this is why they are of interest and have many roles vs just productivity
37
Comparisons of ecosystems:
| -maximum productivity vs average agriculture?
- maximum productivity in some natural communities, e.g. coral reefs (2,000) BUT average agriculture (=644) far below maximum
38
Explain the situation with aquatic ecosystems and the zone of primary productivity
- dependent on light which varies due to the depth aka how much light can penetrate
- all production occurs at a very thin layer at the top of the ocean (50m)...this is why productivity is so low
- once you get below a certain depth there is no primary production (compensation depth - 100m) aka the depth at which where the cost outweighs the benefit
-
39
Photo inhibition?
- too much light can be counted productive and cause damage at no depth for example wrt aquatic ecosystems
40
What nutrients are limiting in oceans and freshwater?
- ocean: N and Fe
- Freshwater: P
- slow down PS
41
Describe the global map of primary productivity patterns in the ocean!
- big open spaces are low in productivity
- vast majority of the ocean is low
- way out in the middle of nowhere = low nutrients...far away from mainland
- closer to coastline = good...shallow war = light can reach the bottom
- if it is shallow the nutrients do not settle out of the system and can be brought back up via mixing
42
How does upwelling affect nutrient supply?(2 types) Also explain the coriolis effect!
- well the earth is obviously spinning
- Equatorial upwelling: N/S running water has to come up and replace it --> two currents running in the opposite direction. Pushes surface water away and brings up the depth water
- Coastal upwelling: earth is spinning, wind comes down and blows the surface area offshore causing the depth water to come up
- otherwise nutrients would stay at the bottom and we would have a difficult time circulating it
- coriolis effect: earth is spinning once around every 24 hours and its not straight up and down..thats why we have different seasons
43
Energy allocation and life form with respect to plants???Generalizations?
- when precipitation reduced, plants allocated more energy to roots than leaves. Results in a reduced photosynthetic activity
- Also reduced biomass in dry habitats; correlated with decreased NPP per unit area
- as conditions change allocations of energy for the organism will change
- differences between terrestrial and aquatic f: what factors are limiting, productivity differences, plants and animal s etc .
* *not much storage of nutrients in terrestrial ecosystems...in aquatic they are dispersed quickly, grazed on then turned over and stored to be recycled later.
44
Does primary production vary with time?
- yep
- seasonal variations in temperature and light cause variations
- year to year variations in productivity due to climate, herbivore abundance or files etc
- Age of plant stands. Older larger plants more production needed to maintain large plant structure
* *new plants add in to standing crop biomass
45
Example of the close relationship between environmental conditions and crops growing?
- as temperature increases so does productivity but after a certain point it goes down
- periods of to, dry weather give rise to low primary productivity of grasses
46
Explain seasonal variation in ocean production (Tropics, Temperate and Polar)!
- Tropics: no primary productivity is going on, thats why the water is so clear. No nutrient s (limited)
- Polar: peak in productivity during summer time because they are limited by lack of light
- Temperate: combination of both. Light is limiting in the winter so no primary productivity is seen
L> Spring boom is a take off in productivity, water becomes super hard to see through. Nutrients get stripped down so much that the become limiting in the ocean. Summer is a quiet time in the water, nutrients are limiting. Fall bloom occurs and there is a slight increase productivity and then it drops off afterwards when light is limiting again.
**temp is not a limiting factor since they are adapted to them
47
Net primary production energy is available to?
- heterotrophic component
| - consumed by herbivores or decomposers locally or after report to another ecosystem
48
Secondary production?
- consumers use energy from primary production for respiration, maintenance and secondary production (growth of new tissue or production of offspring (herbivores, carnivores and omnivores )
49
What is the relationship between primary and secondary production?
- direct relationship
- impossible to have more primary than secondary
- cannot produce more than what was made in the previous
_ herbivore consumption and net primary productivity with herbivore biomass follow nearly the same trend as does herbivore secondary production
50
Efficiency of production:
| - Assimilation?
-portion of food assimilated across gut wall (A) --> how much they have available before respiration
51
Efficiency of production:
| - Assimilation efficiency calc?
Assimilation/Ingestion (A/I)
52
Efficiency of production:
| - Production efficiency calc?
- Production/assimilation (P/A)
53
Efficiency of production:
| - Assimilation efficiencies which types of organisms are the most efficient?
- endotherms and carnivores
54
Efficiency of production:
| - production efficiencies are higher in what types of organisms?
- higher for invertebrates and lowest for endotherms
| * * easier for an ectotherm to produce things vs endotherm (costs a low to maintain temp vs going with the flow yo)
55
What are the two major food chains?
- Grazing and Detrital
56
Explain a grazing food chain!
- source of energy for first level of consumers is living plant biomass or NPP
* *Plant -->herbivore-->carnivore **super simple
57
Explain a detrital food chain!
- source of energy, detritus (dead organic matter from plants and animals )
- this food chain is a major pathway of energy flow in ecosystems with little grazing by herbivores
Ex: grassland ecosystem. 2/3-3/4 of energy not grazed; returned to soil as dead plant material
58
Grazing vs Detrital food chain?
- Grazing: primary producers --> herbivores --> carnivores (heat los/respiration occurs at each )
- Detrital: detritus --> decomposer herbivores --> carnivores (R lost at each)
* * primary producers, herbivores and carnivores all go to detritus with then goes to decomposer herbivores and carnivores. Carnivores prey on herbivores and carnivores
59
To quantify energy flow through trophic levels we need to know what?
- consumption
- ingestion
- assimilation
- respiration
- production
60
Explain example of invertebrate herbivore energy flow!
- 1000 energy is available to go from primary production to the next trophic level
- 800 of it is not consumed
- only 200 goes through - of which 130 is lost via waste. 70 is assimilated (useful work) and absorbed for energy...then 56 is used up for respiration (good chunk is gone to maintain the different mechanisms require for the organism to function)...14 is all that is left to be passed on to the next trophic level
61
Explain consumption efficiency !
- formula : In/Pn-1 ***Pn-1 = energy available from the previous trophic level
- amount of available energy consumed
- production of one trophic level is input to next
- consumption efficiencies determine pathway of energy flow e.g. detrital vs grazing food chain importance
- grazing
* *whatever one group can produce is potentially utilized by the next trophic level BUT it doesn't mean they will use it all! not most important chain in most terrestrial, some aquatic ecosystems
62
Explain the percent of net primary production consumed by herbivores example!
- how many times 100% is consumed
- aquatic macrophytes - a very small portion is ingested completely
- terrestrial: vast majority of it is not grazed very much - not completely by any species...it accumulates and is stored
- differences in life span can attribute to this - phytoplankton it takes a matter of a ay to go through one cycle where as trees it takes years on years
- aquatic algae consume 100% a lot
63
Does energy decrease or increase with each trophic level?
- decrease
- ex: 300 trout are needed to support one man for year. The trout, in turn must consume 90,000 frogs that must consume 27 million grasshoppers that live off of 1,000 tons of grass
64
Explain the trophic level vs energy graph!
- With respect to energy:
- Trophic level 1> Trophic level 2 > Trophic level 3> Trophic level 4 (least)
* * small amount of energy loss within trophic level via respiration, a larger energy loss is found in the transfer between trophic levels
65
Explain transfer between trophic levels!
- even in very productive vegetation only 1-3% of annual incident addition is overrated to food energy
- about only 10% of energy stored in biomass in a given trophic level is concerted to biomass at next level
**Generally biomass of produces > herbivores > carnivores
aka most of the light energy is lost, reflected back, lost in the ground - roughly 90% loss as you go through a level
66
When can the biomass pyramid be inverted ?
- when the primary producers have short life psyches
ex: phytoplankton are smaller : not showing the rate so it is not actually represtend of energy level - would be better
- zooplankton can have a higher biomass because they are continually grazing on phytoplankton
67
Quantifying energy flow:
| - gross production calc?
- net + resp
68
Quantifying energy flow:
| - capture efficiency calc?
- gross production/ total unit s produced
69
Quantifying energy flow:
| - NP=?
- GP- respiration
70
What are the units of energy?
- calories = cal (the amount of heat required to raise the temperature of 1g of water 1C...ex: 15 to 16 C
* *kilocalorie = 1000 calories
* *kilocalorie = 4186 joules
71
Energy flows in what direction?
- one direction, no longer valuable to previous trophic level
- progressively decreases in energy available at each level (increasing cost of respiration)
- efficiency of conversion may increase up the chain
* *approx 90% lost int ransomer from one level to next
