Primary production (Ecosystems) Flashcards
Primary production
The amount of energy that autotrophs convert into useable chemical energy (organic compounds)
Determines amount of energy available for consumption by Herbivores, Carnivores, Detritivores
What is primary production driven by
Driven by availability of solar energy. Not all solar radiation is available for photosynthesis: absorbed, scattered, reflected by clouds/dust, lands on non-photosynthetic surfaces.
Photosynthetic rates are dependant on photosynthetic accessory pigments (chlorophyll, carotenoids, phycobilins)
What is GPP
Gross primary production (GPP): The rate of conversion of light energy to chemical energy (ie biomass) by photosynthesis
What is NPP
Net primary production (NPP): The rate of chemical energy (ie biomass) production after respiration has been subtracted (NPP=GPP-Respiration)
Amount of energy available to consumers
Production is a rate
Generation of new plant material over time (energy or biomass per area per time)
What is NEP
Net ecosystem production (NEP): gross primary production(GPP) - total respiration of all organisms (community respiration)
In rainforests, oceans, coral reefs and deserts, what is the NPP and contribution to global NPP
Rainforests high NPP and large contribution to global NPP
Oceans low NPP large contribution to global NPP
Coral reefs high NPP small contribution to global NPP
Deserts low NPP small contribution to global NPP
Primary production in aquatic systems
Primary prod in aquatic systems is limited by light and nutrients. Light availability limits production to surface waters in freshwater and marine ecosystems
What nutrients is geographic variation in primary production shaped by?
- Iron availability in the central ocean gyres
- Nitrogen limitation in marine coastal waters
- Phosphate limitation in freshwater
Many of these patterns are changing as a result of human activity
Eutrophication from domestic, industrial, and agricultural activity
What is Eutrophication
An overabundance of nutrients in water starts a process called eutrophication. Algae feed on them and bloom. Algae blooms can smell bad, block sunlight, and even release toxins in some cases.
Primary production in terrestrial ecosystems
On large scales, primary production is driven predominantly by climate: Highest production in areas that are warm and wet.
Net primary production correlates with actual evapotranspiration.
On regional and local scales, production constrained by nutrient availability.
Consequently, plants have extensive adaptations to sequester nutrients
Eutrophication and terrestrial ecosystems
Eutrophication impacts terrestrial ecosystems too
In alpine meadows, many plants mutualistic with microbes to survive low nutrient availability
Nutrient addition - switches plant-microbe interactions towards parasitism, and reductions production in some plant species
