Transcript Biogeochemical Cycles

Biogeochemical Cycles
Biogeochemical Cycles
describe the flow of essential
elements from the
environment through living
organisms and back into
the environment.
Fig 4.5 Periodic table of the elements.
© 2003 John Wiley and Sons Publishers
D. T. Krohne, General Ecology
Fig 4.6 Idealized
diagram of the
geologic cycle,
which includes the
tectonic,
hydrologic, rock
and
biogeochemical
cycles.
© 2003 John Wiley and Sons Publishers
CO2 & CH4
15%/year
Modified from D. T. Krohne, General Ecology
Hydrological Cycle
Hydrological Cycle
(water cycle)
1. Reservoir – oceans, air (as water vapor),
groundwater, lakes and glaciers;
evaporation, wind and precipitation
(rain) move water from oceans to
land
2. Assimilation – plants absorb water from the
ground, animals drink water or eat
other organisms which are
composed mostly of water
3. Release – plants transpire, animals breathe
and expel liquid wastes
Hydrological Cycle
1. Reservoir – oceans, air
(as water vapor),
groundwater, lakes and
glaciers; evaporation,
wind and precipitation
(rain) move water from
oceans to land.
2. Assimilation – plants
absorb water from the
ground, animals drink
water or eat other
organisms which are
composed mostly of
water.
3. Release – plants
transpire, animals
breathe and expel liquid
wastes.
Carbon Cycle
Carbon Cycle
(carbon is required for building organic compounds)
1. Reservoir – atmosphere (as CO2), fossil
fuels (oil, coal), durable organic
materials (for example: cellulose).
2. Assimilation – plants use CO2 in
photosynthesis; animals consume
plants.
3. Release – plants and animals release CO2
through respiration and
decomposition; CO2 is released as
wood and fossil fuels are burned.
Fig 4.15 Idealized diagram illustrating
photosynthesis for a green plant (tree) and
generalized reaction.
© 2003 John Wiley and Sons Publishers
Carbon Cycle
1. Reservoir –
atmosphere (as CO2),
fossil fuels (oil, coal),
durable organic
materials (for example:
cellulose).
2. Assimilation – plants
use CO2 in
photosynthesis; animals
consume plants.
3. Release – plants and
animals release CO2
through respiration and
decomposition; CO2 is
released as wood and
fossil fuels are burned.
Fig 4.17 Global flux of carbon, 1850-1990.
© 2003 John Wiley and Sons Publishers
Nitrogen Cycle
50% fertilizer
(Bacteria)
Modified from D. T. Krohne, General Ecology
Nitrogen Cycle
(Nitrogen is required for the manufacture of
amino acids and nucleic acids)
1. Reservoir – atmosphere (as N2); soil (as
NH4+ or ammonium, NH3 or
ammonia, N02- or nitrite, N03- or
nitrate
Nitrogen Cycle
2. Assimilation – plants absorb nitrogen as
either NH4+ or as N03-, animals obtain
nitrogen by eating plants and other
animals. The stages in the
assimilation of nitrogen are as
follows:
Nitrogen Fixation: N2 to NH4+ by
nitrogen-fixing bacteria (prokaryotes
in the soil and root nodules), N2 to
N03- by lightning and UV radiation.
Nitrification: NH4+ to N02- and N02- to N03by various nitrifying bacteria.
Nitrogen Cycle
3. Release – Denitrifying bacteria convert
N03- back to N2 (denitrification);
detrivorous bacteria convert
organic compounds back to NH4+
(ammonification); animals excrete
NH4+ (or NH3) urea, or uric acid.
Nitrogen Cycle
1. Reservoir – atmosphere (as
N2); soil (as NH4+ or
ammonium, NH3 or ammonia,
N02- or nitrite, N03- or nitrate
2. Assimilation – plants absorb
nitrogen as either NH4+ or as
N03-, animals obtain nitrogen by
eating plants and other animals.
3. Release – Denitrifying bacteria
convert N03- back to N2;
detrivorous bacteria convert
organic compounds back to
NH4+ ; animals excrete NH4+,
urea, or uric acid.
Critical Thinking Issue – How are Human
Activities Affecting the Nitrogen Cycle?
Effects of increased use of
nitrogen fertilizer:
• Increased nitric acid in soil:
• Leaching of magnesium and potassium
• Increased aluminum levels
• Plant root damage
• Changes in microbe communities
• Fish kills
• Eutrophication of water bodies
• Nitrates in drinking water
• Global effects on plant based CO2 uptake
© 2003 John Wiley and Sons Publishers
Phosphorus Cycle
Gaseous
phase
D. T. Krohne, General Ecology D. T. Krohne, General Ecology
Modified from D. T. Krohne, General Ecology
Phosphorus Cycle
(Phosphorus is required for the manufacture
of ATP and all nucleic acids)
1. Reservoir – erosion transfers phosphorus to
water and soil; sediments and rocks that
accumulate on ocean floors return to the
surface as a result of uplifting by
geological processes
2. Assimilation – plants absorb inorganic PO43(phosphate) from soils; animals obtain
organic phosphorus when they plants and
other animals
3. Release – plants and animals release phosphorus
when they decompose; animals excrete
phosphorus in their waste products
Phosphorus Cycle
1.Reservoir – erosion transfers
phosphorus to water and soil;
sediments and rocks that
accumulate on ocean floors return to
the surface as a result of uplifting by
geological processes
2.Assimilation – plants absorb
inorganic PO43- (phosphate) from
soils; animals obtain organic
phosphorus when they plants and
other animals
3.Release – plants and animals
release phosphorus when they
decompose; animals excrete
phosphorus in their waste products
Effects of Human Activities
on the Sulfur Cycle
• We add sulfur dioxide to the atmosphere
by:
– Burning coal and oil
– Refining sulfur containing petroleum.
– Convert sulfur-containing metallic ores into
free metals such as copper, lead, and zinc
releasing sulfur dioxide into the environment.
Sulfur
trioxide
Water
Acidic fog and
precipitation
Sulfuric acid
Ammonia
Oxygen
Sulfur dioxide
Ammonium
sulfate
Hydrogen sulfide
Plants
Dimethyl
sulfide
Volcano
Industries
Animals
Ocean
Sulfate salts
Metallic
sulfide
deposits
Decaying matter
Sulfur
Hydrogen sulfide
Fig. 3-32, p. 78
Ecosystems and the Gaia Hypothesis
Ecosystem defined: a community of
organisms and it’s corresponding abiotic
environment through which matter cycles and
energy flows
• Wide
variation in ecosystems
• Boarders can be well defined or vague
• Can be natural or artificial, managed or wild
• Wide range in scale
• Common to all ecosystems: energy flow and
cycling of matter
Gaia Hypothesis(es)
• Life has greatly affected the planetary environment
• This alteration has allowed life to persist
• The Earth is a “super-organism” - Life controls the
environment in a fashion that is equivalent to the way
an organism controls its various systems
• Evolution?
Biogeochemical cycles of
other minerals, such as
calcium and magnesium,
are similar to the
phosphorus cycle.