Energy and production in ecosystems Flashcards
Primary producer
organism that can create its own food and energy
How does Photosynthesis makes higher trophic levels possible?
Provide initial source of energy from the sun and fixes its own carbon to fuel the entire food chain
Heterotrophic
rely on other organisms to consume for energy
Detritus
any dead organism
Detritivores
eat detritus (dead material)
Plants undergo both ____ and _______
photosynthesis and autotrophic respiration
Photosynthesis
Harnesses sun’s energy (electromagnetic energy) to make glucose
6CO2 + 6H20 → C6H12O6 + 6O2
What are sugars made by photosynthesis are used for?
Aerobic respiration and anaerobic respiration
Autotrophic Respiration
where plants use oxygen to break down sugars produced during photosynthesis, releasing energy for growth and other life functions, while also releasing carbon dioxide as a byproduct
glucose + oxygen –> energy released + CO2 + H20
Heterotrophic respiration
glucose + 6O2 –> 6H20 + 6CO2 + 38 ATP
Flux
movement/ transfer of substance between different pools (unit has time)
(gC/m2/year, kCal/m2/year)
Pool
places where substance is stored within ecosystem
Ex. atmosphere, plant biomass, sun’s electromagnetic energy, chemical bonds in plants
(gC/m2, kCal/m2)
Food Chain
series of steps or links created by consumption
GPP: Gross Primary Productivity
total photosynthesis per unit area per unit time
How is primary productivity lost from plants and each trophic levels?
50% of energy at one trophic level used for its metabolism
10% gets eaten while the organisms are alive
40% goes to detritus and will be eaten layer
NPP: Net Primary Productivity
accounts how much overall photosynthesis was done subtracted by carbon and energy lost from plant respiration
GPP - AR
Energy available to herbiviroes and detritivores
NEE: Net ecosystem exchange
the contribution of an ecosystem to the global carbon cycle
net carbon balance of an ecosystem
GPP - (AR + HR)
At equilibrium, NEE should be
0
NPP is driven by
temperature and precipitation
at some point too high temp and precipitation does not help
How are NPP influence by nutrients?
More nutrients including nitrogen, phosphorus, potassium, iron help plants grow for more NPP
How are oceans NPP influenced at nutrients?
Nutrients are key!
NPP high along coasts due to upwelling
Deep ocean currents are nutrient rich and get forced up to surface with sunlight for high NPP
How is NPP effected by human disturbance?
Reduce NPP due to urbanization, pollution, soil erosion
Increase NPP due to fertilizations of crops
Importance of cross ecosystem iron transfer in oceans
Increase in iron helps productivity
Why does iron transfer not help climate change?
Short term effect
Only helps NPP not NEE
Cause dead zone with increase use in oxygen in water
How to Measure NPP
Isolate plant biomass and measure accumulation
Measuring NPP in Grasslands
Plot is burned or mowed yearly
Plant life span is 1 year
Percent lost to herbivores is small
Estimate NPP by measuring standing biomass
Combine above ground NPP with predermined area biomass and below ground NPP with core soil and roots
Measuring NPP in forest
Sum of leaf, woody, and fine root biomass
Measuring NPP in aquatic systems
Difficult as dominant autotrophs (phytoplankton, algae, and cyanobacteria) have short lifespans
Standing biomass not good measure of NPP
Get sample of water, incubate, and measure decrease in CO2 as NPP represents net carbon uptake
