2 KEY CONCEPT 1Ecosystems consist of nonliving (abiotic) and living (biotic) components.
3 KEY CONCEPT 2An ecosystem survives by a combination of energy flow and matter recycling.
4 KEY CONCEPT 3 Earth is a Closed System! Biosphere Carbon cycle PhosphorusNitrogenWaterOxygenHeat in the environmentHeat
5 BIOGEOCHEMICAL CYCLES: ABIOTIC CYCLES GLOBAL RECYLING - A closed pathway where matter cycles from the nonliving environment to living and then back again for reuse.Key feature- nutrients recycle through the earth’s air, land, water, and living organisms.Nutrients are the elements and compounds that organisms need to live, grow, and reproduce.The overall rate of nutrient movement is limited most by decomposition.The rate of nutrient loss is a key characteristic in any ecosystem.
6 Overview of Nutrient Cycling PlantsConsumptionOverview of Nutrient CyclingHerbivoreAssimilationFeces or urineDeathDeathDetritusUptakeSoil nutrient poolDecomposerfood webLoss to erosion or leaching into groundwater
7 Water Cycle Condensation Transpiration Evaporation Precipitation Rain cloudsTranspirationEvaporationPrecipitation to landTranspiration from plantsPrecipitationPrecipitationEvaporation from landEvaporation from oceanSurface runoff (rapid)RunoffPrecipitation to oceanInfiltration and PercolationSurface runoff (rapid)Groundwater movement (slow)Ocean storage
8 Water Cycle Causes wind currents There are strong forces of attraction between molecules of water.Water exists as a liquid over a wide temperature range.Liquid water changes temperature slowly.It takes a large amount of energy for water to evaporate.Liquid water can dissolve a variety of compounds.Water expands when it freezes.Water CycleWater has greatest influence of all non-living components
9 Effects of Human Activities on Water Cycle We alter the water cycle by:Withdrawing large amounts of freshwater.Clearing vegetation and eroding soils.Polluting surface and underground water.Contributing to climate change.
14 Most Important Greenhouse Gases GHGs Source ExamplesWater: H2O Oceans, rivers, plants, soilCarbon Dioxide: CO2 Combustion of fossil fuels, plant respiration, oceans, volcanoesMethane: CH4 Mining operations, combustion, animals, wetlands, landfillsOther GHGs : Nitrous oxide (N2O), Ozone (near surface),Learn more about GHGs:Source: U.S. EPA 2005
15 Nitrogen CycleAvailability of Nitrogen is a limiting factor for primary productivity78% N gas in atmosphereunusable
16 Nitrogen Cycle Ammonification Decomposition by bacteria during decay Bacteria can “fix nitrogen” which means they break apart nitrogen gas and convert it into ammonia or ammonium.AssimilationAbsorption and incorporation of nitrogen by plantsThese nodules are called rhyzomes. They are where the nitrifying bacteria reside. They have a symbiotic relationship with the plantNitrificationAmmonia to nitrates and nitrites by bacteriaThen can be assimilated by plantsDenitrificationDenitrifying bacteria convert nitrates back into N2
17 Effects of Human Activities on the Nitrogen Cycle We alter the nitrogen cycle by:Adding gases that contribute to acid rain.Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone.Contaminating ground water from nitrate ions in inorganic fertilizers.Releasing nitrogen into the troposphere through deforestation.
18 Effects of Human Activities on the Nitrogen Cycle Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined.
19 Phosphorous CycleNo gaseous component (from land to sediment and back to land only)Erosion releases phosphate soil plantsDecomposers phosphate soilDeposited in oceanic sediment unavailable for yearsFertilizers, run off containing animal wastes, and sewage aquatic ecosystems
21 Effects of Human Activities on the Phosphorous Cycle We remove large amounts of phosphate from the earth to make fertilizer.We reduce phosphorous in tropical soils by clearing forests.We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.
23 Effects of Human Activities on the Sulfur Cycle We add sulfur dioxide to the atmosphere by:Burning coal and oilRefining sulfur containing petroleum.Converting sulfur-containing metallic ores into free metals such as copper, lead, and zinc releasing sulfur dioxide into the environment.
24 Acid PrecipitationRain, snow or fog that has a pH value of less than 5.6 because of the carbon dioxide from air dissolved in itAny rainfall has a pH value less than 5.6 is defined as acid rain
25 Acid PrecipitationWhen gas pollutants e.g. sulfur dioxide, nitrogen dioxide dissolve in rain water, various acids are formed.CO2 + H2O H2CO3 (carbonic acid)SO2 + H2O H2SO3 (sulphorous acid)NO2 + H2O HNO2 (nitrous acid) HNO3 (nitric acid)