Lecture 4  material cycling 1 st 2010-2011
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  • 1. MATERIAL CYCLING IN ECOSYSTEMS Lecture 3 NS5 1st 2010-2011
  • 2. THE CYCLING OF MATERIALS IN THE ENVIRONMENT • LAW OF ECOLOGY #2: EVERYTHING MUST GO SOMEWHERE • LAW OF THERMODYNAMICS: ENERGY IS NOT CREATED NOR DESTROYED
  • 3. BIOGEOCHEMICAL CYCLING • The movement of elements and compounds that are essential to life • Materials are transported through organisms, the atmosphere, water and land in a series of CYCLES • “Bio” – life, participation of organisms • “Geo” - abiotic environment as source of nutrients • “Chemical” – nature of substances being cycled
  • 4. BASIC TYPES OF CYCLES • Gaseous type – the reservoir is the atmosphere and/or hydrosphere (e.g. N2, CO2, O2) • Sedimentary type – the reservoir is the Earth’s crust (e.g. Phosphorus) • Linkage type – the reservoir includes major pathways in air, water, and crust (e.g. sulfur)
  • 5. WHEN THE PROBLEMS COME IN • Errors in Nutrient Cycling • A’  A’’  A’’’’  A’ • Pollution – accumulation of a chemical form that is higher than the standards • Non-biodegradable substances – change to form new chemical structure where no organism has yet to utilize it • Reduction of the concentration of other chemical forms – limits growth of the subsequent components of the cycle • Eutrophication - the channeling of a substance to other pathways (greater amounts of phosphates in aquatic systems)
  • 6. INTRODUCING THE CYCLES OF NATURE BIOGEOCHEMICAL CYCLES
  • 7. THE HYDROLOGIC CYCLE OR WATER CYCLE !"#$%&'"(&)*+),-./.012)345678)9$(:;$) <=)
  • 8. PURPOSE: Mediates Nutrient Cycle and A Major Energy Dissipation Pathway • IMPACTS OF HUMAN INTRUSION • More consumption than supply • Pumping waters from aquifers - not a normal part of the water cycle • Garbage and wastes pollute the water and clog drainage systems induces flooding • Asphalting – render the ground impervious to water blocks infiltration POLLUTION: a change in transfer rate of water and nutrients that can lead directly or indirectly to a degradation of human health or degradation of plant and animal life
  • 9. • OXYGEN CYCLE Type: Gaseous (21%) • Major Reservoir: Atmosphere • Forms: Free and Molecular Oxygen • Sources: Photosynthesis from producer AND Photodissociation of Water Vapor • Fate of Free O2: • Reach higher levels of trophosphere and reduced to ozone (provides protection by filtering out the sun's UV rays) • May react with chemicals and organic compounds of the earth’s crust • May be used up in cell respiration which release CO2 to be used by autotrophs to produce more O2
  • 10. IMPACTS OF HUMAN INTRUSION • CFC’s (chlorofluorocarbons) deplete ozone layer “ozone hole” • Eutrophication (nutrient enrichment from agricultural and domestic wastes) leads to depletion of oxygen in water • Combustion of fossil fuels and removal of vegetation (deforestation) deplete the supply of oxygen in the atmosphere
  • 11. CARBON CYCLE • Type: Gaseous Cycle • Major Reservoir : Atmosphere but also calcium carbonate in shells and limestone, as well as fossil fuels • Significance : Major element of organic compounds; building blocks of all biomolecules • Processes • Photosynthesis removes CO2 while respiration and combustion add CO2 to the atmosphere. • CO2 from air and water combine to form bicarbonate (HCO3) – source of carbon for aquatic producers. Carbonic acid makes rainwater also slightly acidic • Similarly, when aquatic organisms respire, CO2 is released and combine with water to form HCO3. HCO3 (water) = CO2 (air)
  • 12. The global carbon cycle includes the earth's atmosphere, oceans, vegetation, soils and fossil fuels
  • 13. CARBON RESERVOIRS
  • 14. CONTROVERSIAL ISSUES ASSOCIATED WITH CARBON CYCLE
  • 15. NITROGEN CYCLE • Type: Gaseous Cycle • Major reservoir – ATMOSPHERE • Importance – Essential for many biological processes, constitutes part of proteins (amino acids), in bases of nucleic acids that make up DNA and RNA • 79% of atmosphere is made up of nitrogen (N2) but this is INERT • It must be fixed for organisms to utilize it
  • 16. IMPACTS OF HUMAN INTRUSION • USE OF NITROGEN FERTILIZERS • NITROGEN OXIDES RELEASED THROUGH COMBUSTION • Human use of nitrogen fertilizers causes runoff, leading to eutrophication in aquatic • Burning of fossil fuel + automobiles : source systems (e.g. eutrophication) of nitrogen dioxide • NITRATES LEACHING INTO • Ozone + PAN Photochemical Smog GROUNDWATER • LIVESTOCK RELEASE OF LARGE AMOUNTS • Nitrogen level in drinking water rises OF AMMONIA (FROM WASTES) • A large rise of nitrogen in drinking water • The ammonia released from wastes of supplies leads to Methemoglobinemia / livestock can have detrimental effects on Blue-Baby Syndrome fish and other organisms • There is reduction in diversity
  • 17. PHOSPHORUS CYCLE • Type: Purely Sedimental • Major reservoir – Earth’s crust • Gradual cycle - It has no gaseous phase • Phosphorous normally occurs in nature as part of phosphate ion. • Most phosphates found as salts in ocean sediments or in rocks. • Over time : geologic processes can bring sediments from ocean to land, and weathering can bring it from land to ocean • Importance • Phosphorous constituent of nucleic acids in DNA, and energy currency of cell ATP. • Phosphorous -also found in bones, in phospholipids which are found in biological membranes.
  • 18. IMPACTS OF HUMAN INTRUSION • Humans mine phosphate ores for use in fertilizer production and detergents • Human actions could lead to eutrophication of aquatic systems which cause algal blooms • Algal blooms cause fish kills
  • 19. SULFUR CYCLE • Type: Sedimentary cycle with atmospheric component • Major reservoir – inorganic sulfur in rocks and fossil fuel • Biological Importance • Sulfur is an important element in protoplasm which is an important component of some amino acids. • Sulfur is part of proteins, vitamins and hormones
  • 20. CONTROVERSIES ASSOCIATED WITH THE SULFUR CYCLE ACID RAIN
  • 21. THE CYCLING OF HEAVY METALS BIOMAGNIFICATION AND BIOREMEDIATION
  • 22. MERCURY • Fish can be contaminated with methylmercury from neighboring industrial plants • They discharge mercury wastes into water • Result : Minamata disease or Mercury Poisoning • Effects : blindness, deafness, lack of coordination, intellectual deterioration
  • 23. CADMIUM • Itai-itai disease is cadmium poisoning, first in Japan 1950 • Cadmium was released into the river by mining companies in the mountains • Causes softening of the bone, and kidney failure • Name of disease derived from painful screams because of severe pain in joints and spine of victims “pain-pain”
  • 24. LEAD • Lead poisoning = Increases level of lead leads to negative effects on nervous and reproductive system • e.g. Lead containing gasoline, Paints, Batteries, Electric Wires, Cables etc
  • 25. HYDROCARBON • DDT – (dichlor-diphenyl- trichloroethane) “organochlorine insecticide” • Banned in 1972 • Exposure to DDT causes eggshell thinning in bird species eg. raptors, eagles, peregrine falcons • Toxic to humans and animals when swallowed or absorbed through the skin
  • 26. BIOLOGICAL MAGNIFICATION • It is the increase in concentration of an element or compound that occurs in the food chain as a result of food chain energetics or degradation of substance. • Accumulation of chemicals in higher predators or in higher trophic levels • Chemical concentration is said to be magnified thousand fold in tissues of higher trophic level organisms • It is important in ecology because : it indicates that solution to certain types of pollution is not dilution because food chains will concentrate the pollutant ANSWER : BIOREMEDIATION
  • 27. NEXT MEETING: POPULATION