Download (N 2 ) into ammonia (NH 3 )

CYCLING IN NATURE
Wed Sept 4/Thurs Sept 5
If you have supplies to turn in, please place them under the window.
AGENDA
•Collect signature pages
•Set up science notebook. This will be a TESTGRADE!
•Stamp and review homework
•Notes: Nutrient Cycles
HOMEWORK
•Complete Pre-Lab: Using a Compound Light Microscope
•QUIZ NEXT CLASS- Flow of Energy and Matter in
Ecosystems
• Ecosystem structure is influenced by the
availability of nutrients and energy.
• The five main elements plants use
include:
 carbon
 oxygen
 hydrogen
 nitrogen
 phosphorous.
Cycles, Alright!
• The elements essential for life
tend to move in cycles.
• Elements are transferred from
the environment, to organisms,
then back to the environment.
Organisms
Environment
• Elements, chemical compounds, and other
forms of matter are passed from one
organism to another and from one part of
the biosphere to another through
biogeochemical cycles.
• Connect biological, geological, and
chemical cycles of the biosphere.
Organisms
Environment
• Cold and warm
ocean currents,
clouds, winds,
and rainfall are
all a part of the
global
hydrologic
cycle. The
hydrologic cycle
is driven by
solar energy.
• What are two ways water moves into the
atmosphere?
• Evaporation- water changes from liquid
form to an atmospheric gas.
• Transpiration: evaporation of water from
leaves of plants.
• It remains as water vapor, clouds, and
ice crystals until it falls back to
earth.
How does water fall back to Earth?
• Condensation- water cools and forms
clouds.
• Precipitation- water falls to earth and
remains on land for about 10 to 120 days.
• Then some of it evaporates or is carried
by rivers and streams to the seas where,
with evaporation, the cycle begins.
• Water is an important way in which
nutrients move into and out of
ecosystems. As the water goes
through the hydrologic cycle, it
carries the nutrients with it.
Raise your hand if
you love the
hydrologic cycle!!!
• Carbon moves in through the atmosphere
and oceans, through organisms, and then
back to the environment as dead
organisms deteriorate.
• Carbon enters the atmosphere through
– respiration,
– fossil fuel burning, and
– volcanic eruptions, which release
carbon from rocks deep in the earth’s
crust.
• Carbon exists as gas in the atmosphereCO2 (carbon dioxide). About half of all the
carbon entering the atmosphere each
year will move into two large “holding
stations”.
• The two places where most of the CO2 is
housed are:
1) oceans
2) plant biomass
• Each year
photosynthesiz
ers capture
airborne CO2
and turn it into
organic
compounds, like
food.
• In aquatic food webs, carbon is turned
into the shells and other hard parts of
marine organisms. When the shelled
organisms die, they sink to they bottom
where they can remain buried for millions
of years.
• This carbon may slowly be converted
into “fossil fuel”:
– gas,
– petroleum
– coal
• Of
all
of
the
nutrients
influencing the growth of land
plants, nitrogen is often in the
shortest supply.
• The atmosphere is the largest
supply of nitrogen, but it is in a
form that cannot be used by
organisms.
• Nitrogen Fixation: process of converting
nitrogen gas (N2) into ammonia (NH3)
• Bacteria that are found in the soil and on
the roots of legumes undergo this
process.
•
Nitrogen fixing bacteria can convert N2 into forms
that can be used in ecosystems. The N2 is turned
into ammonia NH3 by the bacteria. The ammonia
is then used in the production of proteins by
plants.
• N2  NH3 (nitrogen fixation!)
• Plants use the nitrogen in their tissues, the
nitrogen is then transferred to animals when they
consume the plant.
!!! The Nitrogen Cycle Yipee!!!
• Nitrogen is returned to
the environment when
bacteria and fungi
break down nitrogencontaining wastes and
the remains of plants
and animals.
• Denitrification:
conversion of nitrates
into nitrogen gas (N2)
Nutrient Cycles and Acid Rain
• Acid rain is caused by a
chemical reaction that
begins when compounds
like sulfur dioxide and
nitrogen oxides are
released into the air.
• These substances can rise
very high into the
atmosphere, where they
mix and react with water,
oxygen, and other
chemicals to form more
acidic pollutants, known
as acid rain
Volcanoes and acid rain
• Volcanoes are a
natural source of
acid.
Acid Rain
pH Scale
• pH scale- measuring
system that
indicates the
concentration of H+
ions in solution
• Acids- Are
compounds that
donate H+ (below
pH of 7)
• Bases- are
compounds that
donate OH- (above
pH of 7)
• Neutral pH is 7
http://www.ltbenvironmentalproject.com/uploadedImage
s/6-_FAQs/pHscale.jpg