Lyons Environmental Science -Cycles of Matter Worksheet
The hydrologic cycle is the circular pathway of water on Earth from the atmosphere, to the surface, below
ground, and back. Water falls to Earth as precipitation such as rain or snow. Some droplets of water reenter the
atmosphere through evaporation or transpiration, which is evaporation that occurs between plant leaves and
the atmosphere. Water vapor in the atmosphere condenses and forms clouds, from which precipitation falls.
A biogeochemical cycle is the movement of a particular chemical, such as oxygen, carbon, nitrogen, or
phosphorous, through the living and nonliving parts of an ecosystem. In the oxygen cycle, oxygen flows into the
atmosphere as a byproduct of photosynthesis. Organisms take in this oxygen and release it as carbon dioxide
through respiration. Respiration and photosynthesis also figure heavily in the carbon cycle. The cycling of
carbon is important because it is the building block of life.
Carbon dioxide dissolves easily in water. Once there, it may precipitate as a solid rock known as calcium
carbonate (limestone). Corals and algae encourage this reaction and build up limestone reefs in the process.
Carbon dioxide is released from volcanoes. Humans have a great impact on the carbon cycle because when we
burn fossil fuels we release excess carbon dioxide into the atmosphere. Some believe this causes global
warming, because the carbon dioxide in the atmosphere acts like a blanket trapping heat in the atmosphere.
Other human activities that can affect the carbon cycle are agriculture, deforestation, and reforestation.
Nitrogen is used by living organisms to produce a number of complex organic molecules like amino acids,
proteins, and nucleic acids Proteins make up skin and muscle, among other important structural portions of your
body, and all enzymes are proteins. Since enzymes carry out almost all of the chemical reactions in your body,
it's easy to see how important nitrogen is.
78% of the atmosphere is nitrogen; however it cannot be taken up by many living organisms. Bacteria and
lightening convert nitrogen in the air into usable forms. Plants can only take up nitrogen in two solid forms:
ammonium ion (NH4+ ) and the ion nitrate (NO3- ) These forms of nitrogen are used by plants to make amino
acids (proteins) and nucleic acids (DNA and RNA). The activities of humans have severely altered the nitrogen
cycle. Some of the major processes involved in this alteration include: The application of nitrogen fertilizers to
crops has caused increased rates of nitrates into groundwater. The additional nitrogen entering the
groundwater system eventually flows into streams, rivers, lakes, and estuaries. In these systems, the added
nitrogen can lead to eutrophication. Increased amounts of nitrogen from fossil fuel combustion contribute to
acid rain. Livestock ranching and sewage leaching also release a large amount of ammonia into the
environment. This nitrogen enters the soil system and then the hydrologic system through leaching and runoff.
The phosphorous cycle begins when phosphate is released by the erosion of rocks. Plants and fungi can take up
the phosphates with their roots. Phosphorous moves from the producers to the consumers via the food chain.
Phosphorous is returned to the soil through the decomposition of plants and animals. Phosphorous may leach
into groundwater from the soil, settling into sediment. Over time this sediment forms into rocks. When these
rocks erode the, cycle begins again. Human influences on the phosphate cycle come mainly from the use of
fertilizers, manure from feedlots, and sewage treatment plants.
Nutrient Cycles Worksheet
Instructions: On a separate sheet of paper, put your NAME, PERIOD, and the title
“Nutrient Cycles Worksheets.” For each of the following cycles, put the cycle name.
Then write the following sentences or questions. Fill in the blanks using the words
provided in the word bank. Make sure to underline the filled-in words.
Carbon Cycle
Coal
Photosynthesis
Oil
Natural Gas
Cellular Respiration
Burning of fossil fuels
Sugar
Greenhouse
Decayed
1.
2.
3.
4.
Plants use CO2 in the process of __________ to make ___________ & oxygen.
Animals and plants use oxygen in the process of ____________ to make ATP, which makes more CO2.
In the past, deposits of carbon were stored when dead plants and animals ______________.
Today these deposits are burned as fossil fuels. The 3 types of fossil fuels are ___________________,
_________________, and ___________________.
5. More CO2 is released in the atmosphere today than in the past because of _____________________.
6. Too much CO2 in the atmosphere may be responsible for the _______________________ effect, in
which gas molecules in the atmosphere trap heat around the Earth.
7. The chemical equation for photosynthesis is:
Oxygen Cycle
Photosynthesis
Ozone
Waste
Crust
Oceans
Cellular Respiration
1. Plants release 430-470 billion tons of oxygen during the process of ______________________.
2. Atmospheric oxygen in the form of ____________________ (O3) provides protection from harmful
ultraviolet (UV) rays.
3. Oxygen is found everywhere on Earth, from earth’s _________________ (ground & rocks), to the
_____________, where it is dissolved.
4. Oxygen is vital for ________________ by plants and animals, a process which produces CO2 and water.
5. Oxygen is also necessary for the decomposition of _________________ by bacteria and fungi, which
turns it into other elements necessary for life.
6. The chemical equation for cellular respiration:
TURN OVER!
Nitrogen Cycle
Extra Information that You DO NOT have to copy:
78% of the atmosphere is nitrogen; however it cannot be taken up by many living organisms.
Bacteria and lightening convert nitrogen in the air into usable forms. Plants can only take up
nitrogen in two solid forms: ammonium (NH4+ ) and nitrate (NO3- ). These forms of nitrogen are
used by plants to make amino acids (proteins) and nucleic acids (DNA and RNA). The activities of
humans have severely altered the nitrogen cycle. Some of the major processes involved in this
alteration include: The application of nitrogen fertilizers to crops has caused increased rates of
nitrates into groundwater. The additional nitrogen entering the groundwater system eventually
flows into streams, rivers, lakes, and estuaries. In these systems, the added nitrogen can lead to
eutrophication. Increased amounts of nitrogen from fossil fuel combustion contribute to acid
rain. Livestock ranching and sewage leaching also release a large amount of ammonia into the
environment. This nitrogen enters the soil system and then the hydrologic system through
leaching and runoff.
Atmosphere
78%
Nitrogen-fixing
Ammonia
Proteins
Denitrificating
Nitrate
Plants
Animals
Waste
Plants
1. Our atmosphere is made up of________ nitrogen gas.
2. Animals and plants cannot directly use nitrogen gas found in our_______________.
3. Special bacteria “fix” nitrogen in the air so other organisms can use it. These bacteria are called
_________________ bacteria.
4. Organisms use nitrogen to make _______________ and nucleic acids (DNA and RNA).
5. Bacteria break down animal waste and create _________ and _____________, which are nitrogen-rich
products easily used by plants.
6. ____________ bacteria in the soil break down ammonia into the gaseous form of nitrogen, which is not
available for use by plants or animals.
7. In another part of the cycle, animals eat _____________ that contain nitrogen, which is again returned
to the soil by animal ____________ or decaying _______________ and ______________.
TURN OVER!
Water Cycle
Extra Information that You DO NOT have to copy:
The water (hydrologic) cycle is the circular pathway of water on Earth from the atmosphere, to the surface,
below ground, and back. Water falls to Earth as precipitation such as rain or snow. Some droplets of water
reenter the atmosphere through evaporation or transpiration, which is evaporation that occurs between plant
leaves and the atmosphere. Water vapor in the atmosphere condenses and forms clouds, from which
precipitation falls.
Evaporation
Atmosphere
Waste
Condensation
Rain
Transpiration
Groundwater
Lakes and rivers
Oceans
Precipitation
1. Most water on Earth is stored in the ______________.
2. Surface water on Earth includes freshwater found in _______________________.
3. Surface water in oceans and lakes and rivers is turned into vapor (gas) through the process of
________________________________.
4. Water becomes liquid form again in clouds in the ____________________, through the process of
_______________________.
5. Liquid water falls back to Earth as different forms of _________________, such as ___________, snow,
and sleet.
6. Animals release water during respiration and as ________________, such as in urination.
7. Plants loose water through their leaves, which is called ____________________________.
8. Water that is stored underground, such as in aquifers is called _____________________________.
TURN OVER!
Phosphorous Cycle
Extra Information that You DO NOT have to copy:
The phosphorous cycle begins when phosphate is released by the erosion of rocks. Plants and fungi can take up
the phosphates with their roots. Phosphorous moves from the producers to the consumers via the food chain.
Phosphorous is returned to the soil through the decomposition of plants and animals. Phosphorous may leach
into groundwater from the soil, settling into sediment. Over time this sediment forms into rocks. When these
rocks erode the, cycle begins again. Human influences on the phosphate cycle come mainly from the use of
fertilizers, manure from feedlots, and sewage treatment plants. This can put too much phosphorus in bodies of
water, which can result in over-growth of plants and algae, a process called eutrophication. This overgrowth of
plants and algae can result in lowered oxygen levels in the water, possibly killing other aquatic organisms such as
fish and insects.
Pollution
Basins
Overgrowth
Rocks & Minerals
Waste
DNA
Plants
1. Phosphorous is mostly found in ______________.
2. It is an essential nutrient for life, as it makes up important molecules like ______________.
3. In the Phosphorous Cycle, phosphorous moves between the soil and __________, which are eaten by
animals. The animals use phosphorous, and then their ____________ products help return the sulfur
for the next generation of phosphorous in the soil.
4. Some of the phosphorous in soils can be washed away into water __________.
5. Another source of phosphorous comes from man-caused __________________.
6. Too much phosphorous in water leads to plant __________________, strangling all other life in the
water.
TURN OVER!
EXTRA CREDIT – 10 Points Added if you do the Sulfur Cycle!
Sulfur Cycle
Water
Pollution
Sulfuric acid
Volcanoes
Matches
Minerals
H2S
Ground/rock
Insecticide
Rain
1. Sulfur in its pure elemental state is most often found near active ________________________.
2. Sulfur is found in all of Earth’s environments, including the air, the hydrosphere ( ________-portion), the
biosphere (living portion), and the lithosphere (___________-portion).
3. Many sulfates, a solid form of sulfur, come from chemical weathering (breaking-down) of
_______________ that contain sulfur.
4. Another major source of sulfur is from ____________________ caused by man-made activities. These
are mixed with water in the air, falling as ___________ into water basins.
5. The gas, _______, smells like rotten eggs.
6. One of the most important sulfur compounds is the acid ____________________________, which is
used to make fertilizers, automobile batteries, iron and steel, and plastics.
7. Other uses for sulfur include ______________________ (kills insects) and _____________ (used to start
fires).