Primary and Secondary Production Flashcards
physical, chemical and biological are inseparable…
forests, oceans, streams etc. absorb, transform and store energy
ecosystem
a biological community plus all the abiotic factors influencing it
primary production
production of new biomass by autotrophs (measured in biomass, CO2 uptake or O2 output)
- gross is all production
- net is production - respiration
secondary production
production of biomass by heterotrophic consumer organisms feeding on plants, animals, fungi and detritus
what limits primary production?
temperature, moisture, nutrients
highest production occurs in what environments?
warm and moist
annual actual evapotranspiration (AET)
total amount of water that evaporates and transpires off a landscape in a year
- positively correlated with net primary production
- soil fertility accounts for significant variation in production
patterns of aquatic primary production
generally limited by nutrient availability
- depth, sunlight contributes
- upwelling of nutrients near coasts
- phosphorous limits freshwater
- nitrogen limites matine
- runoff from land
diversity effect on production
high diversity of primary production and plant functional group composition = higher productivity
how do consumers affect primary production?
through trophic cascades
trophic cascade?
effects of predators on prey (top-down) that alter abundance, biomass and productivity of a population, community or trophic level (top levels have consequences for lower trophic levels)
- intense grazing can increase grass production (top-down)
secondary production. top down and bottom up
ecosystems with greater primary production generally support more secondary production
- energy is lost through trophic levels (pyramid-shaped)
- top-down (consumers, predators, invasive species)
- bottom up (physical and chemical factors
