quiz 6 ch 18 Flashcards
trophic dynamic view of energy flow
energy transfer w/in ecosystem
concept of energy transfer
group organism w/in ecosystem
Raymond Lindeman trophic dynamic
ecosystem =fundamental to study energy transfer.
as energy is transferred from one trophic level to another energy is degraded
energy degradation due to
limited assimilation
consumer respiration
heat production
energy distribution is appears like
a pyramid
10 % rule
only 10 % energy in trophic level is passed to next level
James Gosz: solar energy flow in temperate deciduous forest
15 % reflected 41% converted to heat 42% absorbed by evapotranspiration 2.2% fixed by plant as gross primary production 1.2% plant respiration 1% primary production
too much energy loss can lead to
insufficient energy to support next trophic level
primary production
energy fixation by autotrophs in ecosystem
rate of primary production
amount of fixed energy over period of time
gross primary production
total amount of energy fixed by autotrophs
net primary production
amount of leftover energy after autotrophs met their metabolic needs
annual actual evapotranspiration
amount of water that evaporates and transpires off landscape annually
Annual actual evapotranspiration of cold dry ecosystems
low
net primary production and annual actual evapotranspiration
positive
differences in soil fertility explains
variation in terrestrial primary production
shaver and Chapin
arctic net primary production was 2x as high on fertilized plots than unfertilized plots
Bowman
N = main nutrient limiting net primary production in dry tundra meadow.
N and P limit production in wet meadow
nutrient availability controls
rate of primary production in freshwater ecosystem
high rates of primary production by marine phytoplankton are concentrated in
areas with higher levels of nutrient availability like continental margins
nutrient availability of open oceans
poo dur to vertical mixing of main nutrient source
graneli
rate of primary production in Baltic Sea is nutrient limited
increased nutrients = increases chlorophyll concentrations
N = limited nutrient
residual variation
proportion of variation not explained by independent variable
dillon and Rigler
environmental factors other than nutrient availability influence phytoplankton biomass
bottom up controls
influence physical and chemical factors of ecosystem
top - down control
influence consumers
carpenter
piscivores and planktivorous fish can cause deviation in primary productivity
carpenter and kitchell
trophic cascade hypothesis.
reduced planktovirous fish populations led to reduced rates of primary production.
absent planktivorous minnows predaceous invertebrates become more numerous.
large herbivorous zooplankton, phytoplankton biomass and rate of primary production declined
trophic cascade hypothesis
consumers on lake primary productivity propagate through food webs
Mc Naughton
Serengeti grazers consume 66% annual primary production.
positively correlates with rainfall quantity.
grazers can increase primary production.
light grazing = insufficient to produce compensatory growth.
heavy grazing reduce plant capacity to recover
compensatory growth
lower respiration rate due to lower biomass
reduce self- shading
improve water balance due to reduced leaf area
ecological efficiency
percentage of energy transferred from one trophic level to the one above
