Chapter 55: Ecosystem Ecology Flashcards
Ecosystem
- Sum of all organisms and abiotic factors of which interact within a designated boundary
Defining spatial boundaries of an ecosystem
?
Ecosystem ecology (def.)
Study of energy flow and the cycling of chemicals among biotic and abiotic components in an ecosystem
How does an ecosystem differ from a community?
- Ecosystem is abiotic and biotic factors
- Community is interaction between species
Ecosystem ecologists study?
Transformation of energy and matter within the ecosystem
Law of Conservation of E
- Energy can’t be created or destroyed (only transferred or transformed)
Law of Conservation of Mass
- mass or matter = amount of an element (used for development, maintenance, or reproduction)
- Matter cannot be created or destroyed
Laws and relation to ecosystem ecology?
- Energy is transformed and matter/nutrients are reused over and over (in a cycle)
- Follow where all of the energy or matter goes in an ecosystem
- Ask which organisms in the ecosystems are most important in determining where the energy and matter go
Primary differences between mass and energy?
- energy is expended
- mass is recycled; cannot be created or destroyed
Detritivores
Organisms that derive energy from detritus (non-living organic matter)
Primary production
- Amount of light energy that is converted to chemical energy by autotrophs in given time period
Sun’s energy as it flows into/out of an ecosystem?
- 10^22 joules per day
- Most hits places devoid of vegetation
- 1% of visible light that hits plant is used in photosynthesis
- Around 1/2 solar radiation absorbed in first 15 meters of water
Gross Primary Production
(GPP) Total amount of light energy converted to chemical energy per unit time
Net Primary Production
(NPP) Total light energy converted minus autotrophic respiration (Ra)
New plant biomass equation
NPP = GPP - Ra
Total biomass accumulation
NEP = GPP - Rt
Two key factors the limit primary production in aquatic ecosystem
- Sunlight
- Nutrients
Eutrophication
- High nutrient levels lead to overproduction of algae (chokes out O2)
Factors limit primary production in terrestrial ecosystems at global/local scale
- Global: Temperature and moisture
- Local: Nutrients, light, space, herbivores
Evapotranspiration
- Amount of water transpired from plants and evaporate from landscape
Relationship between evapotranspiration and primary production
- Higher evapotranspiration rates associated with higher primary production
Secondary production
- Amount of chemical energy in consumers’ food that is converted to own new biomass during given time period
- Not 100% efficient
Trophic efficiency
- How much of production at one trophic level is transferred to the next
Energy transfer isn’t 100% efficient because…
Energy is required for innumerable functions of the organism
Factors that determine how fast detritivores decompose materials?
- Temperature, moisture, nutrient availabiilty
Biogeochemical cycle
Route of an element or compound through an ecosystem
Nitrogen fixation
Transformation of atmospheric nitrogen into NH3
Denitrification
NH4+ –> NO2-
Ecosystem ecologists study nutrient cycling how?
- Study cycling of key materials at small and large scales
