ecosystem ecology (BB10205) Flashcards
ecosystem ecology
organism complex and whole complex of physical factors
Physical/chemical: wind ,currents, heat and geochemistry
Biological: communities, producers, consumers
ecosystem components
producers consumers decomposers abiotic components: - water - atmosphere - soil minerals - climatic variables
emphasis on function not species
pool of energy/matter for each component- how things flow between
Gw predicts
on av temp increase - shift temp distribution and incr occurrence of extreme events
Larger number of extreme hot days, more drought
Less rain on the days rain is light but heavier when it does rain- storms
Heavy precipitation extremes
Why care about ecosystem ecology?
goods and service
understanding of function of ecosystems to improve management because human activities are changing them
ecosystem research core areas
transformations and interactions of energy and matter within an ecosystem
Energy budgets and factors that control energy transfer
monitoring changes
sustainability: carrying capacity (management and harvest), restoration
How human activities affect these processes
productivity
rate of energy capture and conversion to chemical bonds
Primary producers efficiency
99% of solar energy is reflected/not absorbed
Loses some by respiration and rest converted into biomass
GPP
rate at which energy is captured and assimilated by producers. Includes the use of captured energy by the producers for their own metabolism via respiration
NPP
Rate of energy assimilated and converted to biomass by producers in an area
NPP=
GPP-R
GPP %
1% of solar energy captured by PS is GPP
HOw is GPP distributed
60% of GPP respired
40% of GPP converted to biomass/NPP
ways of measuring changes
measuring changes in producer biomass
changes in CO2 uptake and release
O2 uptake and release
Remote sensing
Measuring changes in producer biomass
measure mass of producers at the beginning and end of growing season
Tells you how much biomass has been accumulated
Useful for comparing agric processes
estimates NPP
Variable across years
Changes is CO2 uptake and release
Measure CO2 in a container in the light and dark. Decr in CO2 in the light is NPP, difference between light and dark is GPP (GPP = NPP + resp)
Measuring changes in O2 uptake and release
CO2 disperses too fast in aquatic environments
Measure dissolved O2 instead- similar but reversed relative to productivity
Incr O2 measured in light, Consumption of O2 measured in dark
GPP = NPP (change in O2 in light) +R ( change in O2 in dark)
Remote sensing
can measure from a great distance (planes/satellites)
Using absorbance and reflectance of chlorophyll to map global changes in producer biomass
Reflectance of light of different wavelengths
NPP distribution across earth
Terrestrial systems show highest productivity in the tropics
Tropical rainforests most productive ecosystems
PS works best at high temps and more light- at the equator
Patterns of NPP in aquatic systems
marine systems lower in productivity per unit area
Temp still important, but being near coast more important
Aquatic systems along coasts highly productive per unit area with estuaries and coral reefs most productive
Movement of water affects climate/temp eg gulf stream
Temp and rainfall
positive correlation with productivity
Nutrients
N and P can be limiting to productivity
Most biomasses limited by nutrients- by adding them you incr productivity
What effects PP i aquatic ecosystems
Temp
Light: depth of light penetration alters productivity in the photic zone
Nutrients (N,P,Fe)
secondary production
From producer to 1st consumer
secondary productivity positively correlated to
NPP
suggests more available energy from producers results in more consumer growth and reproduction
