ecosytem ecology Flashcards
heart of ecosystem ecology
fluxes of energy and matter
major energy source
photons of the sun absorbed by photosynthetic organisms
first law of thermodynamics
conservation of energy:
energy changes “states” (wood burns and transforms chemical to heat energy)
energy can move
rate at which autotrophs convert co2 in carbonic compounds
primary productivity
types of autotroph
chemo- : energy from chemical compounds
(oxydation of molecules)
photo- : energy from the sun
organism that only consumes anorganic matter
autroph
organism that only consumes organic matter
heterotroph
secondary production
allocation of biomass in heterotrophs
total rate of photosyn. by autotrophs
FACHBEGRIFF
Gross primary productivity (GPP)
rate of energy storage as organic molecules
FACHBEGRIFF
Net primary productivity (NPP)
NPP=GPP-R
R… cellular respiration
NPP as function of biomass
NPP= deltaB + D + C
deltaB = B(t2) - B(t1)
D = death of plants
C = consumption of plants
light bottle vs dark bottle method
bottles filled from lake oä.
light bottle estimates NPP (photosyn. + respi)
dark bottle estimate R (only respi)
GPP can be measured!
effects on NPP
NPP increases with precipitation and with temperature (solar radiation)
higher temperature -> longer growing season
more percipitation -> more water can be transpired by stomatal activity
warm and cold on NPP
warm and dry -> low NPP
warm and wet -> high NPP (tropics)
cold and anything -> low NPP
combined value of evapo and transpiration
AET = actual evapotranspiration
terrestial: impact of nutrients to NPP
generally increases NPP when nutrients in soil
marine: NPP distribution
shallow and coastal water have highest productivity
upwelling supplies nutrientsfrom bottom sediments
coastal areas receive nutrients from terrestial ecosystems
effects of nutrients in marine
nitrogen stimulates phystoplankton
iron stimulating growth
phosphorus only limiting in coastal and open ocean) -> where not much impact by human
compensation depth
where GPP = R and NPP = 0
NPP in stream ecosystems (limiting?)
when best?
limited by light and nutrients
light is limiting in summer -> tree canopies
nutrients limiting during fall and spring when canopy open and light increases
greatest biomass allocation when light and nutrients enhanced
organic carbon produced in ecosystem
FACHBEGRIFF
AUTOCHORUS CARBON
by plants algea ect
organic carbon “imported” in ecosystem
FACHBEGRIFF
ALLOCHTHONOUS CARBON
dead organic matter transported by river oä
freshwater ecosystem (carbon)
allochthonous carbon dominates (from sorrounding trees ect) dead plant material…
marine ecosystem (carbon)
autochorus input dominates (phytoplankton)
small vs big lake ecosystem (carbon)
small: allochthonous carbon (50%)
big: autochorus carbon (varies seasonaly -> inflow in the lake)
effect of carbon allocation plant
when in leaves -> positive feedback -> more photosynth. -> more carbon ect.
precipitation effect on NPP
less water less carbon alocation to leaves but to roots
ratio roos and shoots
Root-to-shoot (R:S): 0.2 in rainforests, 4.5 in deserts
biomass gain per unit of plants mass (FACHBEGRIFF) examples temperate forest "" grassland open ocean
RNPP = relative net primary production
= grams / gram plants mass / unit time
TF: NPP = 1200 ; RNPP = 0.04
TG: NPP = 550 ; RNPP = 0.031
OO: RNPP = 42
RNPP terrestial vs marine
in terestial much energy has to be used for biomass allocation for stability ect
in marine everything can be dedicated to photosynthesis and reproduction
primary to secondary production
herbivores produce waste (feces), much is used for metabolism for maintenance and acquiring food and performing work
remaining for growth of tissues and reproduction
prim to second in terestial
primary constrains secondary -> bottom up control
primary increase -> secondary increase
prim to second in aquatic
phytopl. productivty is coupled to zoopl. activity
bottom up control
what happens with primary produced shit?
schema…
efficiencies
I = A + W
I… the food ingested
A… assimilated in gut
W… waste
A = R + P
R… respiration
P… production
assimlilation efficiency = A/I
efficiency of extracting energy from food
production efficiency = P/A
efficiency of incorporating food into secondary production
comparing efficiencies of animals
endo vs ecto
herbi vs carni
inverte vs verte
endo more than ecto
carni more than herbi (herbis mus eat non stop to sustain metabolism)
inverte more tha vert
two major food chains
FACHBEGRIFF
grazing (GREEN) food chain:
primary prod. -> herbivores -> carnivores
detrital (BROWN) food chain:
detrius (compost) -> decomposer herbivores -> carnivores
BUT THESE CHAINS ARE VERY INTERCONNECTED!!!
waste of primary -> detrius ect…
carnivores feed on both foodchains
energy diagram trophic levels
available: production of next lower trophic level
losses: respiration and waste
rest is given to next trophic level
efficiencies aquatic vs terestial
what used by second?
much much higher efficiency in water as energy is not used for rooting and defense ect…. BOUYANCY!!!
in marine secondary can eat everything -> in terestial wood is not eaten ect. …
algea 70% consumed
macrophytes 30%
terestial only 17%
measure of transfer of energy between trophic levels
trend?
FACHBEGRIFF
TE = trophic efficiency
TE = P(n)/P(n-1)
production of level n-1 used for production of level n
every trophic level looses much muich energy
biomass of trophic levels
normally gets smaller with each level
but plankton inversed:
because zooplankton live much longer than phytoplankton -> therefore more biomass
