Download Biogeochemical Cycles - Ms. Mogck`s Classroom

Cycles
 rapid cycling: substances cycle
between nutrient rersevoirs
(holding areas) quickly
 slow cycling: substances
accumulate and are unavailable to
organisms
 Evaporation from the
land (water to the
atmosphere)
 As it cools, water vapor
condenses and eventually
falls as precipitation
 Ground water transports
the water in the soil
Plants pull water from the
ground and lose it to the air
through transpiration
Photosynthesis and
Cellular Respiration
Energy
from sun
C6H12O6
+ 6O2
6CO2 +
6H2O
Energy
released
Slow cycle
 Living organisms play an
important role in the slow
cycling of carbon
 Trees act as carbon
reservoirs (carbon sinks)
until they die
 in the ocean,
phytoplankton and algae
reproduce creating biomass
 a small % drifts to the
ocean floor and is converted
to fossil fuel deposits
(over millions of years)
Boreal forest is recognized
as a significant carbon sink
due to the accumulation of
peat (muskeg)
Human Impact on Carbon
 Burning fossil fuels release
stored carbon into the
atmosphere (as carbon
oxides)
 Wildfires also return carbon
from trees into the atmosphere
(as carbon oxides)
Nitrogen
 makes up 78.1% of the
Earth’s atmosphere
 N2 is nitrogen gas
Nitrogen Fixation
 Some bacteria convert
atmospheric nitrogen into
ammonium
 these bacteria live in the lumpy
roots of legumes and share their
ammonium with the plants
Ammonium
 also produced when
decomposers break down
organic matter (called
ammonification)
 NH4  NO2-  NO3-
Denitrification
 denitrifying bacteria
convert nitrite or nitrate
back to nitrogen gas
 occurs in environment with
very little oxygen
Human Impact on Nitrogen
 Fertilizers contain nitrogen that
may run off into water and create
harmful algal blooms
 Burning fossil fuels contain
nitrogen that leads to
photochemical smog and acid
rain
 Wildfires convert N2 into
usable nitrates, ammonia
and ammonium.
 Wildfires also warm the
soil making it less acidic
allowing for greater growth
of plants
Phosphorous
 essential nutrient available
in limited quantities
 concentrated in living
organisms
 part of DNA and ATP
 phosphorus does not cycle
through the atmosphere
 found in soil and water and
gradually released out of
rocks
 animals eat milk, grain, meat
to get phosphorus
 plants can only use
phosphorus if it’s a phosphate
3(PO4 ) which dissolves in
water
 phosphorus keeps the growth
of producers in balance, but it
also limits the growth of crops
 how might the increased
availability of phosphorus
affect the aquatic ecosystem?
Algal Bloom
 overgrowth of algae
 caused by excess phosphorus
 as decomposers break down
the organic matter, they use up
the oxygen resulting in the
death of fish