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

The Four Spheres Scientists divide regions on the Earth into four spheres: –Lithosphere – Earth’s crust, soil, rocks etc. –Hydrosphere – all water on Earth –Atmosphere – all gases in the air –Biosphere – all life Each sphere contains many natural cycles that contribute to our survivalEach sphere contains many natural cycles that contribute to our survival

The Biosphere Biosphere means “life-zone” and was coined by Dr. Vladimir Vernadsky The biosphere encompasses all living things It is divided into separate, but interdependent units called ecosystems

The Biosphere cont. Ecosystems are well-defined habitats hosting systems of interacting organisms.Ecosystems are well-defined habitats hosting systems of interacting organisms. The continuation of life within the biosphere depends on the constant recycling of nutrients.The continuation of life within the biosphere depends on the constant recycling of nutrients. Nutrients are chemical ingredients found on Earth, which are necessary for the continuation of life.Nutrients are chemical ingredients found on Earth, which are necessary for the continuation of life.

The Nutrient Cycle Nutrients come from decaying biomaterial (dead things) that become gases (move into atmosphere) and solids and liquids that are released into the soil and water for living plants and animals to use as nutrientsNutrients come from decaying biomaterial (dead things) that become gases (move into atmosphere) and solids and liquids that are released into the soil and water for living plants and animals to use as nutrients This is referred to as the nutrient cycle – there are four nutrient cyclesThis is referred to as the nutrient cycle – there are four nutrient cycles

The Carbon Cycle The Carbon cycle is a nutrient cycleThe Carbon cycle is a nutrient cycle It is the movement of carbon from the atmosphere into plants, animals, and the soil, and then back into the atmosphere againIt is the movement of carbon from the atmosphere into plants, animals, and the soil, and then back into the atmosphere again Carbon is an essential component of life on Earth.Carbon is an essential component of life on Earth.

The Carbon Cycle (cont’d) Plants take carbon dioxide from the atmosphere and use it to produce their own food through photosynthesisPlants take carbon dioxide from the atmosphere and use it to produce their own food through photosynthesis The plants form carbohydratesThe plants form carbohydrates They also release oxygenThey also release oxygen

Animals breathe oxygen and eat carbon – storing plantsAnimals breathe oxygen and eat carbon – storing plants The animals, in turn, breathe out carbon dioxideThe animals, in turn, breathe out carbon dioxide When both plants and animals die, decomposition releases carbon dioxide into the air and it is used againWhen both plants and animals die, decomposition releases carbon dioxide 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 – it helps to regulate Earth’s temperatureCarbon dioxide is also a greenhouse gas – it helps to regulate Earth’s temperature When there is vast clear cutting and burning of forests, massive amounts of carbon is released into the atmosphere and carbon dioxide-processing plants are destroyed.When there is vast clear cutting and burning of forests, massive amounts of carbon is released into the atmosphere and carbon dioxide-processing plants are destroyed.

The Carbon Cycle (cont’d) This creates an imbalance affecting the greenhouse effectThis creates an imbalance affecting the greenhouse effect Too much carbon dioxide in the air can increase the global temperature (global warming) – like on planet Venus where there is too much carbon dioxide in the air.Too much carbon dioxide in the air can increase the global temperature (global warming) – like on planet Venus where there is too much carbon dioxide in the air.

The Nitrogen Cycle The nitrogen cycle is a nutrient cycleThe nitrogen cycle is a nutrient cycle Nitrogen is the most plentiful element in Earth’s atmosphere – 78%Nitrogen is the most plentiful element in Earth’s atmosphere – 78% Nitrogen has to change to ammonia and various compounds called nitrates before it is useful to living thingsNitrogen has to change to ammonia and various compounds called nitrates before it is useful to living things The Nitrogen Cycle

This is accomplished by microscopic bacteria living on the roots of legumes (alfalfa, peas, beans, and clover)This is accomplished by microscopic bacteria living on the roots of legumes (alfalfa, peas, beans, and clover) An exchange takes place between plants and the bacteria – plants take in nitrogen compounds, the bacteria receive carbohydratesAn exchange takes place between plants and the bacteria – plants take in nitrogen compounds, the bacteria receive carbohydrates The plant converts the ammonia and nitrates into proteinsThe plant converts the ammonia and nitrates into proteins The Nitrogen Cycle Cont’d

The Nitrogen Cycle All life on earth depends on these bacteriaAll life on earth depends on these bacteria When animals eat the plants they use the proteins and other nitrogen compounds to build amino acids – the building block of lifeWhen animals eat the plants they use the proteins and other nitrogen compounds to build amino acids – the building block of life When animals produce waste, or die, decomposition breaks down the amino acid proteins back into ammonia and nitratesWhen animals produce waste, or die, decomposition breaks down the amino acid proteins back into ammonia and nitrates The Nitrogen Cycle (Cont’d)

The Nitrogen Cycle Cont’d These nitrates are reabsorbed into water, soil and plant roots or fixed again by the bacteriaThese nitrates are reabsorbed into water, soil and plant roots or fixed again by the bacteria This bacteria can release free nitrogen in the atmosphere through denitrification – the cycle then repeats.This bacteria can release free nitrogen in the atmosphere through denitrification – the cycle then repeats.

The Oxygen Cycle The Oxygen cycle is a nutrient cycleThe Oxygen cycle is a nutrient cycle The majority of oxygen is produced by the respiration (breathing) of plantsThe majority of oxygen is produced by the respiration (breathing) of plants Oxygen is a by-product of photosynthesis 90% of all oxygen is replaced through the respiration by algae in the world’s oceansOxygen is a by-product of photosynthesis 90% of all oxygen is replaced through the respiration by algae in the world’s oceans The Oxygen Cycle

The Oxygen Cycle (cont’d) Plants release oxygen into the airPlants release oxygen into the air Some oxygen reacts with carbon in the air to produce carbon dioxideSome oxygen reacts with carbon in the air to produce carbon dioxide Some is breathed in by animals and breathed out as carbon dioxideSome is breathed in by animals and breathed out as carbon dioxide The Oxygen Cycle

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

The Water Cycle (cont’d) The water cycle is a nutrient cycleThe water cycle is a nutrient cycle Water must be constantly recycled through the atmosphere as water vapour and back to Earth’s surfaceWater must be constantly recycled through the atmosphere as water vapour and back to Earth’s surface The Water Cycle

Water vapour is the result of evaporation of bodies of water (oceans, lakes, etc.) and transpiration where water is taken up by plant roots and released to the air through leavesWater vapour is the result of evaporation of bodies of water (oceans, lakes, etc.) and transpiration where water is taken up by plant roots and released to the air through leaves The Water Cycle

The Water Cycle (cont’d) In the atmosphere this water vapour collects as clouds, condenses, and falls to the Earth as precipitationIn the atmosphere this water vapour collects as clouds, condenses, and falls to the Earth as precipitation It then runs into rivers, lakes, oceans, and percolates down through soil as ground waterIt then runs into rivers, lakes, oceans, and percolates down through soil as ground water The groundwater dissolves nutrient so plants can use them as foodThe groundwater dissolves nutrient so plants can use them as food The Water Cycle

The Water Cycle Cont’d Some groundwater filters into permeable rocks like sandstone or limestone and can be stored in empty layers between rocks called aquifersSome groundwater filters into permeable rocks like sandstone or limestone and can be stored in empty layers between rocks called aquifers The top layer of the stored water is called the water tableThe top layer of the stored water is called the water table The Water Cycle

The Water Cycle (cont’d) Humans extract water from the water table and use itHumans extract water from the water table and use it This water returns through sewage and waste disposal where it evaporates and the cycle begins again.This water returns through sewage and waste disposal where it evaporates and the cycle begins again. The Water Cycle

Suggested Activity Activity 7Activity 7 Please read pages 48 – 53 of your text. Take special note of the illustrated diagrams of each cycle of the biosphere.Please read pages 48 – 53 of your text. Take special note of the illustrated diagrams of each cycle of the biosphere. Create four concept maps each outlining one cycle of the biosphere: water, carbon, oxygen, and nitrogen.Create four concept maps each outlining one cycle of the biosphere: water, carbon, oxygen, and nitrogen. In no less than a page discuss how each of these cycles are interconnected and interdependent. In no less than a page discuss how each of these cycles are interconnected and interdependent.