2 Recycling in the biosphere Remember:Energy is NOT recycledMatter IS recycledBiological systems do not use up matter; they transform it.In other words, the same molecules are passed around again and again within the biosphere.We are breathing the same oxygen atoms that dinosaurs might have!
3 Biogeochemical Cycles Recycle matter within the biosphereBiological, geological, and chemical aspects of the biosphere are connected and continually recycled, or passed, from one organism to another and from one part of the biosphere to anotherThe two most important biogeochemical cycles are: the water cycle and nutrient cycles
4 The Water Cycle All living things require water to survive Water moves between bodies of water, atmosphere, and land
5 Water Cycle TermsDuring the day, the sun heats the environment, which causes water molecules to enter the atmosphere through evaporation or transpirationEvaporation = Water changes from liquid to atmospheric gasTranspiration = Water evaporates from the leaves of plants
6 Water Cycle Terms (Continued) The warm, moist air filled with water vapors becomes cool as it rises.This leads to condensation = water vapor (gas) turns into liquid water, forming cloudsPrecipitation = the water droplets within the clouds become large enough to fall to Earth in the form of rain, snow, sleet, or hail
7 Water Cycle Terms (Cont.) Surface RunoffMost of the precipitation that falls to the Earth runs along the surface of the ground until it enters a body of waterPrecipitation can also seep into the soil and enter plants through their rootsOnce runoff enters a body of water or seeps into the ground, the water molecules will evaporate or transpire again
8 Water Cycle Condensation Precipitation Evaporation Transpiration Run offSeepageRoot uptake
9 Nutrient CyclesNutrients = all chemical substances that an organism needs to sustain lifeHelp organisms build tissues and carry out essential life functionsLike water, nutrients are passed between organisms and the environment through biogeochemical cycles.
10 Nutrient Cycles (Continued) Nutrients are in short supply for most ecosystemsRecycling nutrients becomes essential for ecosystems to functionKeeps a constant flowPrevents chemicals from reaching toxic levels of concentrationThree most important nutrient cycles are:Carbon, Nitrogen, and Phosphorus cycles
11 The Carbon Cycle Carbon is the key ingredient of living tissue Carbon is found in:organisms,oceans, air, and certaintypes of rocks
12 The Carbon Cycle (Cont.) CO2 (Carbon Dioxide)Makes up atmosphereReleased into atmosphere by organisms breathing, volcanic activity, burning fossil fuels, and vegetationReleases into ground through decomposition of organic matterTaken in by plants in photosynthesis
13 The Carbon Cycle (Cont.) There are four main processes involved in the carbon cycle:1. Biological = photosynthesis, respiration, and decomposition2. Geochemical = erosion and volcanic activity3. Mixed Biogeochemical = burial and decomposition4. Human Activities = mining, cutting & burning forest, burning fossil fuels
14 E. Steps of The Carbon Cycle Carbon enters the atmosphere from breathing and combustionProducers use carbon dioxide in photosynthesis.These producers then release oxygen.Animals inhale the oxygen and exhale carbon dioxide. Animals also feed on the plants. The animals and plants eventually die.Decomposers eat the dead plants and animals. The carbon that was in animal and plants is then returned to the atmosphere as carbon dioxide.
16 The Nitrogen CycleAll organisms require nitrogen to make amino acids (which are used to build proteins)Nitrogen gas (N2) makes up 78% of Earth’s atmosphereNot usable by most organismsNitrogen containing substances such as ammonia (NH3), nitrate ions (NO3-), and nitrite ions(NO2-) are found in waste from organisms and in dead and decaying organic matterThese are usable forms of nitrogenHumans add nitrogen to the biosphere through nitrate (fertilizers)
17 The Nitrogen Cycle (Cont.) Only certain bacteria can use nitrogen gas directlyFound in soil and on roots of plants called legumes (beans, peas, peanuts, etc.)They convert it to ammonia through nitrogen fixationOther bacteria convert ammonia into nitrates & nitritesProducers use it to make proteins, and consumers eat producers and reuse nitrogen to make proteinsWhen organisms die, decomposers return nitrogen to soil as ammoniaAmmonia is taken up by producers (again)Other soil bacteria convert nitrates into nitrogen gas through denitrification, which releases nitrogen back into the atmosphere
19 Simplified Nitrogen Cycle Organic wastes(from plants and animals) add nitrogen to the soil.Bacteria in the soil convert the nitrogen into forms plants can use.Plants use nitrogen in the soil to grow, develop, and produce seeds.Plants are eaten by animals and people. The organic waste (which contains nitrogen) is returned to the soil again.
20 The Phosphorus Cycle Phosphorus is essential to living organisms Forms part of life-sustaining molecules such as DNA and RNAPhosphorus is not common in the biosphereDoes not enter the atmosphereExists on land in rock and soil minerals, and in ocean sedimentsPhosphate is released as rocks and sediments gradually wear downOn land, phosphate washes into rivers and streams, where it dissolves and eventually makes its way to oceans
21 The Phosphorus Cycle (cont.) Runoff/Collection:Erosion transfers phosphorus to water and soil; sediments and rocks that accumulate on ocean floors return to the surface as a result of uplifting by geological processesAbsorption/ConsumptionPlants absorb inorganic phosphate from soils; animals obtain organic phosphorus when they eat plants and other animalsDecomposition/ReleasePlants and animals release phosphorus when they decompose; animals excrete phosphorus in their waste products