Production Flashcards
All the organisms and the physical environment of a given place, including energy flow and nutrient cycling
Ecosystem
Two principal ecosystem processes
Energy flow and chemical cycling
Explain energy flow
Energy flows through an ecosystem (sunlight) which is converted into chemical energy by autotrophs which are then consumed by heterotrophs and is converted into heat
True or false: Chemical elements are continually recycled
True; Chemical elements (such as C and N) are cycled among biotic and abiotic components of ecosystem
These two transform energy and matter in ecosystems
Photosynthesis and feeding relationships
Generation of chemical energy by autotrophs
Primary production
Total amount of carbon fixation by autotrophs in energy rich molecules
Gross primary production
Describes organisms that use photosynthesis
Photoautotrophic
Describes organisms that use chemosynthesis
Chemoautotrophic
Leaf area of plants per unit of ground area
Leaf area index
Amount of energy captured by autotrophs that contributes to biomass
Net primary production (NPP)
Net primary production is equal to?
Gross primary production - Autotrophic respiration
Is equal to: GPP-AR-HR
GPP - Gross Primary Production
AR - Autotrophic respiration
HR - heterotrophic respiration
Net Ecosystem Production or net ecosystem exchange
If NEE>0, it is a ______
Carbon sink, it absorbs more carbon than it releases
If NEE<0, it is a _______
Carbon source, releases more carbon than it absorbs
Above ground NPP varies as a function of?
Leaf Area Index
Key variables controlling global variation in terrestrial NPP
Water and Temperature
T/F NPP increases with decreasing precipitation
False, NPP increases with increasing precipitation
Total amount of water transpired plus evaporated (a function of water availability and solar energy)
Annual Actual Evapotranspiration (AET)
T/F Terrestrial Primary production increases w/ AET
True
T/F Primary production in grasslands decreases with greater annual precipitation?
F, increases
States that Nutrient limitation to plant growth could be traced to a single limiting nutrient
Liebig’s Law of the Minimum
Controls rates of primary production in freshwater ecosystems
Nutrient availability
Highest rates of marine primary production take place where?
along continental margins and in shallow seas
How are continental margin nutrients renewed?
By land runoff and bottom sediment disruption
Middle of oceans have low NPP, why?
Vertical mixing is blocked by a permanent thermocline (no nutrient upwelling) and surface water of tropical oceans are nutrient limited
Limitation based on physio-chemical factors
Bottom-up controls
Limitation based on consumers
Top-down controls
Calculated from satellite measurements of reflectance in red and infrared wavelengths
Global pattern of Terrestrial Chlorophyll
Terrestrial NPP is concentrated where?
Concentrated at the equator
Marine NPP is concentrated where?
Concentrated along the coast
Describe the Global Pattern of NPP
NPP patterns coincide with patterns of climate and upwelling
Amount of chemical energy in consumers’ food converted to consumer biomass
Secondary Production
Is equal to Ingestion - Respiration - Egestion
Net Secondary Production (NSP)
Egestion: Losses via urine and feces
What does NSP become?
Heterotrophic biomass
Most NSP in most ecosystems occur where
In detritivores
