Primary production Flashcards
What is meant by primary production?
The amount of energy that autotrophs convert into usable chemical energy (organic compounds)
Global energy budget determines the amount of energy available for consumption by:
- herbivores
- detrivores
- carnivores
Primary production is driven by?
Solar energy
What happens to 1% of visible light that strikes photosynthetic organisms?
converted into chemical energy
what are photosynthetic accessory pigments?
chlorophyll/carotenoids/phycobilins
What is gross primary production?
GPP - the rate of conversation of light energy to chemical energy (e.g biomass) by photosynthesis
What is net primary production?
NPP - the rate of chemical energy (e.g biomass) production after respiration has been subtracted
Npp = ?
GPP minus respiration
Forest standing stock is typically greater than grassland standing stock however…
NPP of forests is typically smaller than NPP of grasslands
Rainforests =
High NPP
Oceans =
Low NPP
Coral reefs =
high NPP
Deserts =
Low NPP
Contributions to global NPP
Rainforests and oceans = large
Deserts and coral reefs = small
What is primary production in aquatic ecosystems limited by?
Light and nutrients
Light availability limits what?
Production to surface waters in freshwater and marine ecosystems
Geographic variation in primary production is largely shaped by nutrients:
- iron availability in central ocean gyres
- Nitrogen limitation in marine costal waters
- Phosphate limitation in freshwater
Large scales, primary production is driven mostly nay what?
Climate - highest productivity in areas that are warm and wet (higher NPP)
On regional and local scales, production constrained by what?
Nutrient availability
