Lec 24 (Primary Production) Flashcards
- What is Primary Production?
- What is the biggest source of primary production?
- How else can primary production occur?
The fixation of energy by autotrophs in an
ecosystem.
Biggest source of primary production is
photosynthesis by plants, phytoplankton, and
cyanobacteria.
Also can occur via chemosynthesis by some
species of bacteria
Primary productivity?
-amount of energy fixed by autotrophs over an interval of time (rate!)
-In the case of photosynthesis… Rate at which energy
from the sun used to make sugars by plants
-What is this 6CO2 + 6H2O → C6H12O6
-Photosynthesis
-What are the Two Measures of Primary Productivity?
Gross Primary Production
(GPP)
Net Primary Production
(NPP)
-What is Gross Primary Production
(GPP) and an example?
The total amount of energy fixed
by all the autotrophs in the
ecosystem.
Example:
GPP = Photosynthesis
-What is Net Primary Production
(NPP) and an example?
The total amount of energy fixed
by all the autotrophs in the
ecosystem, minus the cost
associated with its fixation.
Example:
NPP = Photosynthesis - Respiration
Why do we need to know the difference between GPP and NPP??
NPP is the amount of energy available to consumers in
an ecosystem.
How to measure ecosystem-level
primary production?
-Using Remote Sensing
-What is remote sensing? How does it work? What does it use?
-Science of acquiring information about the Earth’s surface without being in contact with it
-Sensing and recording
reflected or emitted energy
-To do this, we use cameras and sensors attached to satellites
Terrestrial Primary Production is affected by?
Mainly limited by temperature and moisture
Actual Evapotranspiration (AET)
Soil fertility
-What is Actual Evapotranspiration (AET)?
The total amount of water that evaporates and transpires off a landscape during a given time period, measured in mm water.
• Measure that accounts
for both temperature
and precipitation, as
AET is affected by both.
-Talk about Terrestrial Primary Production and
Soil Fertility
- Adding fertilizers can increase primary production of some plants while also decrease primary production of others. This due to different plants occupying different niches thus they have different requirements.
- Soil Fertility is due to factors like nutrient availability of nitrogen, phosphorus, potassium
Aquatic Primary Production is affected by?
Mainly limited by nutrient availability.
Freshwater Patterns/Marine Patterns
Aquatic Primary Production Freshwater Patterns.
Higher phosphorus concentrations are associated with greater algal biomass
As algal biomass increases so does the rate of primary production
Eutrophication?
nutrient enrichment of a water body
through natural processes or pollution, generally causing rapid algal growth and reduce dissolved oxygen levels