The Biosphere Carbon CycleCarbon Cycle Nitrogen CycleNitrogen Cycle Oxygen CycleOxygen Cycle Water CycleWater Cycle

The BiosphereThe Biosphere• Carbon Cycle Carbon Cycle

• Nitrogen Cycle Nitrogen Cycle

• Oxygen Cycle Oxygen Cycle

• Water Cycle Water Cycle

The Four SpheresThe Four Spheres

Scientists divide regions on the Earth into Scientists divide regions on the Earth into

four spheres: four spheres: – Lithosphere – Earth’s crust, soil, rocks etc. Lithosphere – Earth’s crust, soil, rocks etc. – Hydrosphere – all water on Earth Hydrosphere – all water on Earth – Atmosphere – all gases in the air Atmosphere – all gases in the air – Biosphere – all life Biosphere – all life

• Each sphere contains many natural cycles that Each sphere contains many natural cycles that contribute to our survivalcontribute to our survival

The BiosphereThe BiosphereBiosphere means “life-zone” and was coined Biosphere means “life-zone” and was coined by Dr. Vladimir Vernadskyby Dr. Vladimir Vernadsky

The biosphere encompasses all living things The biosphere encompasses all living things It is divided into separate, but It is divided into separate, but interdependent units called ecosystems interdependent units called ecosystems

The Biosphere cont.The Biosphere cont.

• Ecosystems are well-defined habitats hosting Ecosystems are well-defined habitats hosting systems of interacting organismssystems of interacting organisms..

• The continuation of life within the biosphere The continuation of life within the biosphere depends on the constant recycling of nutrients. depends on the constant recycling of nutrients.

• Nutrients are chemical ingredients found on Nutrients are chemical ingredients found on Earth, which are necessary for the continuation Earth, which are necessary for the continuation of life.of life.

The Nutrient CycleThe Nutrient Cycle

• Nutrients come from decaying biomaterial Nutrients come from decaying biomaterial (dead things) that become gases (move into (dead things) that become gases (move into atmosphere) and solids and liquids that are atmosphere) and solids and liquids that are released into the soil and water for living released into the soil and water for living plants and animals to use as nutrientsplants and animals to use as nutrients

• This is referred to as the This is referred to as the nutrient cycle – nutrient cycle – there are four nutrient cyclesthere are four nutrient cycles

The Carbon CycleThe Carbon Cycle

• The Carbon cycle is a nutrient cycle The Carbon cycle is a nutrient cycle

• It is the movement of carbon from the It is the movement of carbon from the atmosphere into plants, animals, and the atmosphere into plants, animals, and the soil, and then back into the atmosphere soil, and then back into the atmosphere againagain

• Carbon is an essential component of life Carbon is an essential component of life on Earth. on Earth.

The Carbon Cycle (cont’d)The Carbon Cycle (cont’d)

• Plants take carbon dioxide from the Plants take carbon dioxide from the atmosphere and use it to produce their atmosphere and use it to produce their own food through own food through photosynthesisphotosynthesis

• The plants form The plants form carbohydratescarbohydrates

• They also release They also release oxygenoxygen

• Animals breathe oxygen and eat carbon – Animals breathe oxygen and eat carbon – storing plants storing plants

• The animals, in turn, breathe out carbon The animals, in turn, breathe out carbon dioxide dioxide

• When both plants and animals die, When both plants and animals die, decomposition releases carbon dioxide decomposition releases carbon dioxide into the air and it is used again into the air and it is used again

The Carbon Cycle (cont’d.)The Carbon Cycle (cont’d.)


• Carbon dioxide is also a greenhouse gas – Carbon dioxide is also a greenhouse gas – it helps to regulate Earth’s temperature it helps to regulate Earth’s temperature

• When there is vast clear cutting and When there is vast clear cutting and burning of forests, massive amounts of burning of forests, massive amounts of carbon is released into the atmosphere carbon is released into the atmosphere and carbon dioxide-processing plants are and carbon dioxide-processing plants are destroyed.destroyed.


• This creates an imbalance affecting the This creates an imbalance affecting the greenhouse effect greenhouse effect

• Too much carbon dioxide in the air can Too much carbon dioxide in the air can increase the global temperature (global increase the global temperature (global warming) – like on planet Venus where warming) – like on planet Venus where there is too much carbon dioxide in the there is too much carbon dioxide in the air.air.

The Nitrogen CycleThe Nitrogen Cycle

• The nitrogen cycle is a nutrient cycle The nitrogen cycle is a nutrient cycle • Nitrogen is the most plentiful element in Nitrogen is the most plentiful element in

Earth’s atmosphere – 78% Earth’s atmosphere – 78% • Nitrogen has to change to Nitrogen has to change to ammoniaammonia and various and various

compounds called compounds called nitratesnitrates before it is useful to before it is useful to living things living things



• This is accomplished by microscopic This is accomplished by microscopic bacteria living on the roots of legumes bacteria living on the roots of legumes (alfalfa, peas, beans, and clover) (alfalfa, peas, beans, and clover)

• An exchange takes place between plants An exchange takes place between plants and the bacteria – plants take in nitrogen and the bacteria – plants take in nitrogen compounds, the bacteria receive compounds, the bacteria receive carbohydrates carbohydrates

• The plant converts the ammonia and The plant converts the ammonia and nitrates into proteins nitrates into proteins

The Nitrogen Cycle Cont’dThe Nitrogen Cycle Cont’d


• All life on earth depends on these bacteriaAll life on earth depends on these bacteria• When animals eat the plants they use the When animals eat the plants they use the

proteins and other nitrogen compounds to proteins and other nitrogen compounds to build build amino acidsamino acids – the building block of life – the building block of life

• When animals produce waste, or die, When animals produce waste, or die, decomposition breaks down the amino acid decomposition breaks down the amino acid proteins back into ammonia and nitrates proteins back into ammonia and nitrates

The Nitrogen Cycle (Cont’d)The Nitrogen Cycle (Cont’d)

The Nitrogen Cycle Cont’dThe Nitrogen Cycle Cont’d

• These nitrates are reabsorbed into water, These nitrates are reabsorbed into water, soil and plant roots or fixed again by the soil and plant roots or fixed again by the bacteria bacteria

• This bacteria can release free nitrogen in This bacteria can release free nitrogen in the atmosphere through the atmosphere through denitrification –denitrification – the cycle then repeats. the cycle then repeats.

The Oxygen CycleThe Oxygen Cycle

• The Oxygen cycle is a nutrient cycle The Oxygen cycle is a nutrient cycle

• The majority of oxygen is produced by The majority of oxygen is produced by the respiration (breathing) of plants the respiration (breathing) of plants

• Oxygen is a by-product of photosynthesis Oxygen is a by-product of photosynthesis 90% of all oxygen is replaced through the 90% of all oxygen is replaced through the respiration by algae in the world’s oceans respiration by algae in the world’s oceans


The Oxygen Cycle (cont’d)The Oxygen Cycle (cont’d)

• Plants release oxygen into the air Plants release oxygen into the air

• Some oxygen reacts with carbon in the Some oxygen reacts with carbon in the air to produce carbon dioxide air to produce carbon dioxide

• Some is breathed in by animals and Some is breathed in by animals and breathed out as carbon dioxide breathed out as carbon dioxide


• More oxygen is taken back by plant roots More oxygen is taken back by plant roots reversing photosynthesis producing reversing photosynthesis producing carbon dioxide and water – this, in turn, carbon dioxide and water – this, in turn, combines with soil nutrients allowing combines with soil nutrients allowing plants to grow plants to grow


The Water Cycle (cont’d)The Water Cycle (cont’d)

• The water cycle is a nutrient cycle The water cycle is a nutrient cycle

• Water must be constantly recycled Water must be constantly recycled through the atmosphere as water vapour through the atmosphere as water vapour and back to Earth’s surface and back to Earth’s surface

The Water CycleThe Water Cycle


• Water vapour is the result of Water vapour is the result of evaporationevaporation of bodies of water (oceans, lakes, etc.) of bodies of water (oceans, lakes, etc.) and and transpirationtranspiration where water is taken up where water is taken up by plant roots and released to the air by plant roots and released to the air through leaves through leaves



• In the atmosphere this water vapour In the atmosphere this water vapour collects as clouds, condenses, and falls to collects as clouds, condenses, and falls to the Earth as precipitation the Earth as precipitation

• It then runs into rivers, lakes, oceans, It then runs into rivers, lakes, oceans, and percolates down through soil as and percolates down through soil as ground water ground water

• The groundwater dissolves nutrient so The groundwater dissolves nutrient so plants can use them as food plants can use them as food


The Water Cycle Cont’dThe Water Cycle Cont’d

• Some groundwater filters into permeable Some groundwater filters into permeable rocks like sandstone or limestone and can rocks like sandstone or limestone and can be stored in empty layers between rocks be stored in empty layers between rocks called called aquifersaquifers

• The top layer of the stored water is called The top layer of the stored water is called the the water table water table



• Humans extract water from the water Humans extract water from the water table and use it table and use it

• This water returns through sewage and This water returns through sewage and waste disposal where it evaporates and waste disposal where it evaporates and the cycle begins again. the cycle begins again.


Suggested ActivitySuggested Activity

• Activity 7Activity 7• Please read pages 48 – 53 of your text. Take Please read pages 48 – 53 of your text. Take

special note of the illustrated diagrams of each special note of the illustrated diagrams of each cycle of the biosphere. cycle of the biosphere.

• Create four concept maps each outlining one Create four concept maps each outlining one cycle of the biosphere: water, carbon, oxygen, cycle of the biosphere: water, carbon, oxygen, and nitrogen.and nitrogen.

• In no less than a page discuss how each of these In no less than a page discuss how each of these cycles are interconnected and interdependent. cycles are interconnected and interdependent.

Documents

The Biosphere Carbon CycleCarbon Cycle Nitrogen CycleNitrogen Cycle Oxygen CycleOxygen Cycle Water CycleWater Cycle