NUTRIENT CYCLESNUTRIENT CYCLES: ECOSYSTEM TO ECOSPHERESlide 3Nutrients: The Elements of LifeA GENERALIZED MODEL OF NUTRIENT CYCLING IN AN ECOSYSTEMNutrient Compartments in a Terrestrial EcosystemUptake of Inorganic Nutrients from the SoilThe Atmosphere Is a Source of Inorganic NutrientsSome Processes By Which Nutrients Are RecycledCARBON, HYDROGEN AND OXYGEN CYCLES IN ECOSYSTEMSSlide 11PHOSPHOROUS CYCLE IN ECOSYSTEMSNITROGEN CYCLE IN ECOSYSTEMSSources of Nitrogen to the SoilBiological Sources of Soil NitrogenAtmospheric Sources of Soil NitrogenAgricultural Supplements to Soil NitrogenBiological Nitrogen FixationNitrificationUptake of Nitrogen by PlantsAmmonificationDenitrificationSlide 23NUTRIENT LOSS IN ECOSYSTEMS INUTRIENT LOSS IN ECOSYSTEMS IINUTRIENT LOSS IN ECOSYSTEMS IIIGLOBAL NUTRIENT CYCLESGLOBAL WATER CYCLE IGLOBAL WATER CYCLE IIGLOBAL WATER CYCLE IIIGLOBAL WATER CYCLE IVGLOBAL CARBON CYCLE IGLOBAL CARBON CYCLE IIGLOBAL CARBON CYCLE IIIGLOBAL NITROGEN CYCLE IGLOBAL NITROGEN CYCLE IIGLOBAL NITROGEN CYCLE IIISlide 38NUTRIENT CYCLES READINGS: FREEMAN Chapter 54NUTRIENT CYCLES: ECOSYSTEM TO ECOSPHERE•Nutrient cycling occurs at the local level through the action of the biota.•Nutrient cycling occurs at the global level through geological processes, such as, atmospheric circulation, erosion and weathering.NUTRIENT CYCLES•The atoms of earth and life are the same; they just find themselves in different places at different times.•Most of the calcium in your bones came from cows, who got it from corn, which took it from rocks that were once formed in the sea.•The path atoms take from the living (biotic) to the non-living (abiotic) world and back again is called a biogeochemical cycle.Nutrients: The Elements of Life•Of the 50 to 70 atoms (elements) that are found in living things, only 15 or so account for the major portion of living biomass.•Only around half of these 15 have been studied extensively as they travel through ecosystems or circulate on a global scale.Na SODIUMMn MANGANESEFe IRONCl CHLORINEP PHOSPHORUSAl ALUMINUMS SULFURMg MAGNESIUMSi SILICONK POTASSIUMCa CALCIUMN NITROGENH HYDROGENC CARBONO OXYGENA GENERALIZED MODEL OF NUTRIENT CYCLING IN AN ECOSYSTEM•The cycling of nutrients in an ecosystem are interlinked by an a number of processes that move atoms from and through organisms and to and from the atmosphere, soil and/or rocks, and water.•Nutrients can flow between these compartments along a variety of pathways.Nutrient Compartments in a Terrestrial Ecosystem•The organic compartment consists of the living organisms and their detritus.•The available-nutrient compartment consists of nutrients held to surface of soil particles or in solution.•The third compartment consists of nutrients held in soils or rocks that are unavailable to living organisms.•The fourth compartment is the air which can be found in the atmosphere or in the ground.Uptake of Inorganic Nutrients from the Soil•With the exception of CO2 and O2 which enter though leaves, the main path of all other nutrients is from the soil through the roots of producers.•Even consumers which find Ca, P, S and other elements in the water they drink, obtain the majority of these nutrients either directly or indirectly from producers.The Atmosphere Is a Source of Inorganic Nutrients•The atmosphere acts as a reservoir for carbon dioxide (CO2), oxygen (O2) and water (H2O).•These inorganic compounds can be exchanged directly with the biota through the processes of photosynthesis and respiration.•The most abundant gas in the atmosphere is nitrogen (N2);about 80% by volume. Its entry into and exit from the biota is through bacteria.Some Processes By Which Nutrients Are Recycled•Cycling within an ecosystem involves a number of processes.•These are best considered by focusing attention on specific nutrients.CARBON, HYDROGEN AND OXYGEN CYCLES IN ECOSYSTEMS•C, H & O basic elements of life; making up from about 98% of plant biomass.•CO2 and O2 enter biota from the atmosphere.•Producers convert CO2 and H2O into carbohydrates (CH2O compounds) and release O2 from water.•Producers, consumers and decomposers convert CH2O compounds, using O2, back into CO2 and H2O.CARBON, HYDROGEN AND OXYGEN CYCLES IN ECOSYSTEMS•Carbon and oxygen cycle come out of the air as carbon dioxide during photosynthesis and are returned during respiration.•Oxygen is produced from water during photosynthesis and combines with the hydrogen to form water during respiration.PHOSPHOROUS CYCLE IN ECOSYSTEMS•Phosphorus, as phosphate (PO4-3), is an essential element of life.•It does not cycle through atmosphere, thus enters producers through the soil and is cycled locally through producers, consumers and decomposers. •Generally, small local losses by leaching are balanced by gains from the weathering of rocks.•Over very long time periods (geological time) phosphorus follows a sedimentary cycle.NITROGEN CYCLE IN ECOSYSTEMS•Nitrogen (N2) makes up 78% of the atmosphere.•Most living things, however, can not use atmospheric nitrogen to make amino-acids and other nitrogen containing compounds.•They are dependent on nitrogen fixing bacteria to convert N2 into NH3(NH4+).Sources of Nitrogen to the Soil•Natural ecosystems receive their soil nitrogen through biological fixation and atmospheric deposition.•Agricultural ecosystems receive additional nitrogen through fertilizer addition.Biological Sources of Soil Nitrogen•Only a few species of bacteria and cyanobacteria are capable of nitrogen fixation.•Some are fee-living and others form mutualistic associations with plants.•A few are lichens.Atmospheric Sources of Soil Nitrogen•Lightning was the major source of soil nitrogen until recent times when the burning of fossil fuels became a major source of atmospheric deposition.•Nitrogen oxides come from a variety of combustion sources that use fossil fuels. In urban areas, at least half of these pollutants come cars and other vehicles.Agricultural Supplements to Soil Nitrogen•Various forms of commercial fertilizer are added to agricultural fields to supplement the nitrogen lost through plant harvest.•Crop rotation with legumes such as soybeans or alfalfa is also practiced to supplement soil nitrogen.Biological Nitrogen Fixation•Nitrogen fixation is the largest source of soil nitrogen in natural ecosystems.•Free-living soil bacteria and cyanobacteria