biogeochemical cycle (PP24) Flashcards
what is primary productivity
Quantity of biomass produced by primary producers
what is gross primary production (GPP_
Gross Primary Production (GPP): total quantity of biomass that a producer creates
Quantity of carbohydrates produced via photosynthesis
what is net primary production (NPP)
Net Primary Production (NPP): actual stored biomass available to consumers
what is the NPP formula
GPP minus biomass consumed by plant respiration (R)
NPP = GPP – R
in J/m2/year (Energy) or g/m2/year (Mass)
when is the NPP formula used?
Used when considering ecological efficiency
what is secondary productivity
Rate at which consumers convert chemical energy into biomass DIAGRAM IN SLIDES GO LOOK NOW
what is the anthropocene
Modern geological period – the age of humankind
Prefix “anthro” denotes human
what is the ecological footprint
Measures the land area needed to support a population living at a certain quality of life
Incorporates all resource need (food, energy, shelter, etc.)
Hallmark: land use & rise in greenhouse gas levels
what are the 4 important biogeochemical cycles?
nitrogen, oxygen, carbon, phosphorous
what is the main goal of the biogeochemical cycles
Cycling of important organic compounds in water and earth
what are biogeochemical cycles
Movement of chemical elements & molecules through biotic (“bio-“) & abiotic (“geo-“) components of an ecosystem
what is the water cycle and where is it found
Transportation of water via evaporation, transpiration, condensation, precipitation, & groundwater / surface water movement Found in: Oceans: 97% Ice (glaciers, polar caps): 2% Lakes, rivers, groundwater: 1%
know water diagram on slodes
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EXPLAIN the nitrogen cycle
Important ingredient of amino acids, nucleotides
Atmosphere = 80% N2
Atmospheric N2 ‘fixed’’ by bacteria to form ammonia (NH4+), usable by plants
Other bacteria convert waste nitrogen back to N2
explain phosphorus cycle
Important ingredient of nucleic acids, bones, & ATP
Important source of energy
Depends on rock weathering (slow process of erosion)
P trapped in rocks is released into soil → absorbed by producers → consumers → back too soil (decomposition)
what causes an increase of phosphorus in groundwater and soil? and are these natural or human impact
sewage, fertilizer and detergents
human
what can an increase of phosphorus cause ?
increase of biological growth
what is the human impact on the nitrogen cycle
↑ N in groundwater from sewage & fertiliser
Issues with drinking water
↑ in algae & cyanobacteria → ↓ O2 availability (anoxia) in lakes → ↓ fish (suffocation)
Intensive agriculture removes N from soil
Acid rain due to ↑ nitric acid
↓ soil pH & ↑ nutrient leaching (e.g. calcium)
what does an increase of nitrogen in water cause and what is the consequence of that
it causes an increase of growth of algae and cyanobacteria which therefore decreases O2 available in lakes (called anoxia) which therefore leads to the suffocation of fish.
what is a consequence of increase of acid raid due to the increase of nitric acid?
decrease in soil pH and increase in nutrient leaching
what is the duration of the short term carbon cycle
Takes place over the course of ~1 year
definition of sink and source
Sink: location that stores carbon
Source: location that releases carbon
what does the short term carbon cycle involve
Involves fluxes of carbon through different sinks
what is the process of the short term carbon cycle
Consider flow of carbon from organisms into the atmosphere & back again
Carbon is released into the atmosphere by respiration
Carbon is taken out of the atmosphere by autotrophs through photosynthesis
are carbon levels always constant or do they fluctuate
Carbon levels fluctuate over the course of a year
Must consider seasonal changes
Majority of plants found in the northern hemisphere (Eurasia, North America, much of Africa)
what is a natural cause for carbon level fluctuation?
seasonal changes
what seasons is there less photosynthesis (ie. an increase of atmospheric CO2 levels)?
Atmospheric CO2 levels increase during late fall & winter (less photosynthesis)
what seasons is there lower levels of CO2?
spring and summer
what is the duration of the long term carbon cycle?
Takes place over the course of thousands or millions of years
why is the long term carbon cycle more complex than the short term carbon cycle
More complex – need to consider carbon reservoirs
what is a carbon reservoir
Reservoir: area in which carbon is stored over long periods