Transcript Bio20 Ch2 my pptx - Cochrane High School

Cycles of Matter
Earth is a closed system
Living organisms need matter to cycle
because they are crucial for energy
and structural building blocks
Essential Ecosystem Services $$$$$
WATER (hydrologic cycle)
• 71% of Earth is water. (So why wasn’t it called Aqua?)
The amount of water in the biosphere
is finite. It is recycled through the
hydrological cycle.
(So you could be drinking dinosaur pee)
Hydrologic Cycle
WATER – ESSENTIAL FOR ALL LIFE
• Water is essential for humans and ecosystems. Drought and
poor water quality can affect water availability and impact
humans and the environment.
And only 3% of it is drinkable!
WATER’S SPECIAL PROPERTIES
Water exists in the environment as a solid, a liquid, and a gas
WATER’S SPECIAL PROPERTIES
Water is polar, allowing it to dissolve and transport a wide range
of materials
The charged ends dissolve a wide variety of
substances (nutrients, minerals, toxins), brings
them into the water cycle and moves them all over
the Earth through the atmosphere, ground and
surface water, connecting ecosystems that are
separated by great distances.
And microscopically – in cells and
organisms
Unicellular organisms that live in water absorb
needed dissolved substances
Blood, a water-based solution, transports
molecules of nutrients and wastes organisms
Nutrients dissolved in water get
transported through plants
All living chemical reactions are
basically in water
Did you know you are a walking bag of about
400 simultaneous chemical reactions?
Water is a great moderator of Earth’s
climates and the internal T of
organisms
Water’s high specific heat capacity
• As a liquid evaporates, the surface of
the liquid that remains behind cools Evaporative cooling.
• Evaporative cooling moderates
temperature in lakes and ponds and
prevents terrestrial organisms from
overheating.
• Evaporation of water from the leaves
of plants or the skin of animals
removes excess heat.
Human Impacts
• Acid precipitation: dead water systems, no
maple syrup!
Human Impacts
Climate change: increase in global temperatures
increases evapotranspiration and drought
Human Impacts
Increase in human population increases
demand for water. Some say the next world
war will be over water.
Human Impacts
Algal blooms (eutrophication) and creeping
dead zones owing to agricultural and human
wastes, fertilizers
Creeping Dead Zones
Health Hazards
Polluted drinking water:
• bacteria and viruses from sewage and
agricultural waste (cholera, food poisoning,
hepatitis) – every 10 seconds a child dies from
polluted drinking water.
• pesticides, industrial chemicals, heavy metals
• radioactive materials
Death from Unsafe Water
WATER AND CYCLING OF MATTER
• The hydrologic cycle plays a central role in nutrient cycles
(biogeochemical cycles). This flow chart demonstrates only some of the
interactions between these cycles.
precipitation
legumes
(nitrogen
fixation by
bacteria)
photosynthesis
carbon and oxygen
cycles
plants use
nitrate as a
nitrogen
source
sulfur and
phosphorus
used by plants
acid
deposition
(sulfur cycle)
weathering and
erosion release
sulfur and
phosphorus
trapped in rocks
CARBON/OXYGEN CYCLE
CARBON/OXYGEN CYCLE
Carbon Sinks (storage)
Largest carbon sink: the ocean
• dissolved CO2 in the water
• methane hydrates (CH3• H2O) trapped in
ocean floor
Human Impacts
Deforestation and burning of fossil fuels
contributes to climate change and global
warming
Nitrogen Cycle
Nitrogen is a structural component of DNA and
protein. It is crucial for leaf growth and making
chlorophyll the pigment that is necessary for
photosynthesis.
NITROGEN CYCLE
The atmosphere is 78% N2(g). However, most organisms cannot
use N2 (g) but they can use ammonium (NH4+) and nitrate (NO3-)
NITROGEN CYCLE
The atmosphere is 78% N2(g). However, most organisms cannot use N2 (g) but they can use
ammonium (NH4+) and nitrate (NO3-). Nitrogen fixing bacteria (found in nodules in legumes
– clover, peas, alfalfa) and in the soil change N2  NH4+ by nitrogen fixation. Decomposers
also supply ammonium when they decompose dead organisms by ammonification.
NITROGEN CYCLE
The atmosphere is 78% N2(g). However, most organisms cannot use N2 (g) but they can use
ammonium (NH4+) and nitrate (NO3-). Nitrogen fixing bacteria (found in nodules in legumes
– clover, peas, alfalfa) and in the soil change N2  NH4+ by nitrogen fixation. Decomposers
also supply ammonium when they decompose dead organisms by ammonification.
NITROGEN CYCLE
Nitrogen fixing bacteria (found in nodules in legumes – clover, peas,
alfalfa) and in the soil change N2  NH4+ by nitrogen fixation.
NITROGEN CYCLE
Decomposers also supply ammonium when they decompose
dead organisms by ammonification.
NITROGEN CYCLE
Nitrifying bacteria in the soil convert the ammonium to nitrite
and nitrate. Plants can use either ammonium or nitrates for
growth and building chlorophyll.
NITROGEN CYCLE
Denitrifying bacteria complete the cycle and return N2(g) to the
atmosphere. A similar cycle occurs in the water.
NITROGEN CYCLE
NITROGEN FIXATION – N2 gas to NH4+ (ammonium)
• Nitrogen-fixing bacteria that live in the roots of clover and alfalfa
(legumes) and in soil convert the nitrogen gas (from the atmosphere)
to ammonium (NH4+)
• AMMONIFICATION – organic wastes (from dead plants & animals) are
converted by decomposers to ammonium
+
NH4
NITROGEN CYCLE
• NITRIFICATION– bacteria (aerobic) in the soil convert ammonium to
nitrites (NO2) and then nitrates (NO3)
• ASSIMILATION – plants uptake NO3 (nitrates) which is dissolved in the
water, to be used for photosynthesis
Add oxygens
NITROGEN CYCLE
• DENITRIFICATION – bacteria convert nitrates back to N2 which returns
to the atmosphere to complete the cycle
N2
Human Impact
Agriculture removes nitrogen from the soil. We
add it back by annual crop rotation (croplegume-crop-legume) or fertilizers.
Human Impact
Excess nitrogen in fertilizers and animal waste
 algal blooms and creeping dead zones
Lake Ontario
The Nitrogen Cycle
• http://www.teachersdomain.org/asset/lsps07
_int_nitrogen/
THE SULFUR CYCLE
Sulfur is needed for proteins and vitamins in living organisms. Bacteria
are essential to this cycle, just like the nitrogen cycle. Plants need
sulfur as sulfate (SO42-)
Volcanos, low tide smells from
decomposition, deep sea vents
Human Impact
Humans release large amounts of sulfur into the
air: industries, burning fossil fuels, sour gas
 acid precipitation (sulfurous acid)
Kills water systems, damages plants and leaches
nutrients from the soil
THE PHOSPHORUS CYCLE
Phosphorus is essential for life (DNA, ATP, bones, teeth) but is only in limited
quantities on Earth. Keeps producers in check, but limits crop production.
THE PHOSPHORUS CYCLE
• Phosphorus is found in living organisms, land, and water, but it does
not cycle through the atmosphere. It comes originally from rocks, is
released by weathering and becomes phophate (PO43-) which living
organisms can use.
Human Impact
Detergents and fertilizers add phosphates to our
water  algal blooms
Learning Check
Can you fill in the blanks on the BLM cycles?
Can you ace your Ch2/3 practice test?
Can you do your checklist?