Ecological Energetics Flashcards
What’s the bulk of life on earth made up of
Green plants
99.9% by weight
What is compensation point
At metabolic equilibrium energy gained through photosynthesis = energy lost through respiration
What’s gross primary production
Energy (or carbon) fixed via photosynthesis per unit time
Net primary production is
Energy (or carbon) fixed via photosynthesis - energy (or carbon) lost via respiration per unit time
What are 2 possible direct measurement approaches to measure primary production
Measure gas exchange
Measure increase in plant biomass
How does the gas exchange method work in measuring primary production
Measure changes in the concentrations of O2 or CO2 in the surrounding air.
In daylight CO2 uptake ~ net primary production
In night CO2 release ~ respiration
Aquatic system light/dark bottle method
How does harvest method work in measuring primary production
Measure the biomass of plant material produced in a unit of time.
Account for loss due to death or consumption by herbivore
How much do oceans contribute to net primary production
Due to their size 48.5%
What controls the rate of primary production
Limite of light penetration restrict photosynthetic primary producers to surface waters
What is the key limiting factor of primary production in marine area
Nitrates.
Main sources of iron in the ocean
Upwelling of deep waters
Terrestrial export
Aeolian (wind blown) dust
How does primary production in ocean capture carbon from atmosphere
Phytoplankton in surface waters convert atmospheric CO2 to OM which fuels marine food webs.
15% of the OM sinks to deep sea, 0.1% of it gets trapped in sediments
How do autotrophs derive energy
From the sun and materials from non living sources
How do heterotrophs derive energy
Pick up energy and materials by eating living matter
How do they measure secondary production in lab
O2 consumption, CO2 output and heat production from confined animal measured directly
