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Ecology unit 5

Kelly Chamberlain 196.213 English 92 cards

Cards in this deck (92)

  1. 1Steps in photosynthesis cycle (3)1. CO2 from atmosphere + soil water forms sugar
    2. Animals eat plants and use carbon to build tissues
    3. Animals return CO2 to environment by breathing and death
  2. 2Reservoirs of Carbon (2)CO2 in atmosphere and carbon in earth crust
  3. 3Significance of Carbon cycle globally (3)Driving force for other element cycles
    Photosynthesis/respiration
    Greenhouse effect and warming
  4. 4Long term carbon cycles (2)Silication
    Coalification
  5. 5Silicate cycle (4)Transformation of silicate rocks to carbonate rocks
    1.Atmospheric CO2 dissolves in rain, forming carbonic acid
    2. Carbonic acid dissolves silicate rocks and releases cations
    3. Products travel to oceans
    4. CO2 expelled to atmosphere via volcanic sea vents
  6. 6How do plants accelerate mineral weathering?Secrete organic acids
  7. 7Effect of warm temperatures on plants?Promotes weathering, soil formation, plant growth and root activity
  8. 8Coalification cycleBurial of organic matter
    Warm temps: Water accumulates forming hydromorphic soil and increased aquatic vegetation and detritus
    Cold periods: Vegetation and detritus becomes buried under mineral sediments
  9. 9Role of microbes in carbon cycleMajor decomposers that break down organic matter returning CO2 to atmosphere and C to soil
  10. 10What does decomposed organic matter by microbes becomeMatter becomes microbial biomas and CO2
    A fraction of carbon in matter becomes protected in soil
  11. 11Major components of plant residues (5)Carbohydrates: Starch, cellulose and hemicellulose
    Lignin
    Proteins
    Lipids
  12. 12Starch digestionVia Amylase
    Polymer of glucose units, high energy
    Accessible to most microbes
  13. 13Cellulose & Hemicellulose structure and digestionCellulose - Linear polymer of glucose
    Hemicellulose - Surrounds cellulose
    Enzyme - Cellulase
    Microbes break down cellulose and hemicellulose via cellulase, high energy. Easy to digest
  14. 14Lignin structure and digestionComplex structure that is hard to decompose, surrounds cellulose. Microbes only break down lignin to reach cellulose.
    Digested via oxidation - free radicles released to break down lignin, CO2 released
  15. 15Brown Rot and soft rotFungi which decompose polysaccharides associated with lignin
  16. 16White rotFungi which truly decomposes lignin and the sugars associated with lignin
  17. 17Protein digestionProtein bonds hydrolysed by protease enzymes to release amino acids
  18. 18Lipid digestionPlants store lipids as fats and lipids make up waxes. Lipids digested Via lipases
    Dcomposition is slow as lipids are hydrophobic
  19. 19Physical Protection of Organic matter in soilProtection occurs in micropores where microbes cant access them, or in pores where the water current is discontinuous so microbes don't have access
  20. 20Chemical protection of organic matter - Surface areaIn clay soil, Iron ppts on clay particles and organic matter attaches to iron. Ppts increase surface area and increase amount of organic matter
    Energy required to remove matter from ppts
  21. 21Chemical protection of organic matter - Chemical bondingOrganic matter is amphiphilic. Polar region faces minerals in soil and attracts cations
  22. 22Physical role of organic matterBinds particles to forms aggregates
    reduces erosion
    increases water capacity
    Increases tilth
  23. 23Chemical role of Organic matterNutrient cycling
    Retains cations
    Buffers pH
    Filters contaminants
  24. 24Biological role of organic matterSource of C and energy to microbes
    Inactivate some pesticides
    Enhance degradation of pesticide residues
  25. 25Major reservoirs of Nitrogen (3)Atmosphere - most unreactive
    Igneous rocks
    Sedimentary rocks
  26. 26Inorganic vs organic nitrogenInorganic in Atmosphere, organic in Soil, oceans and animals
    Organic N less reactive than inorganic N
    N is not reactive until fixed
  27. 27Nitrogen transformations in soil (8)Fixation
    Immobilisation/Mineralisation
    NH4+
    Nitrification
    Denitrification
    NH3 volatilisation
    Leaching
  28. 28FixationIn Prokaryotes
    Conversion of atmospheric N2 to NH3
  29. 29Haber Bosch synthesisConverts unreactive N2 to reactive NH3, used for fertilisers
    Requires lots of energy for transformation
  30. 30Biological fixation of NitrogenRhizobium bacteria in nodules, require nitrogenase enzyme. Plants supply energy to rhizobium which fixes N for plant
    N2 reduced to NH3, requires anoxic environment
  31. 31Immobilisation of NMicrobial conversion of NH4+ and NO3- (mineral nitrogen) into organic N, requires carbon
  32. 32MineralisationUnreactive organic N converted to reactive inorganic N
    Organic N in proteins degraded by enzymes forming amino acids and amines which are converted to Ammonium
  33. 33Function of urea in soilsAdded via fertiliser or animal waste
    Hydrolysed to NH4+, increasing soil pH, NH3 released to atmosphere
  34. 34Activity of NH4+ in soil (5)Uptake by plants
    Immobilisation by microbes
    Retention in soil particles
    Loss through ammonia - NH3 volatilisation
    Conversion to nitrite and nitrate (nitrification)
  35. 35NitrificationOxidation of NH4+ to NO3-
    Microbes release energy during process
    require oxygen
    Microbes are acid sensitive, produce acids to control their chemical environment
  36. 36Ammonia volitilisationNH4+ converted to NH3 in soil and NH3 is lost to atmosphere
  37. 37Nitrate LeachingInorganic nitrogen in soil: NH4+ and NO3-
    Significant environmental pollutants
    Causes eutrophication and forms N2O greenhouse gas
  38. 38DenitrificationAnaerobic bacteria use nitrate as oxidant for respiration when O2 levels are low, high moisture, presence of C substrate
    Forms N2O
  39. 39Nitrification InhibitorsRestrict NH4+ conversion to NO3- so reduce NO3- conversion to N2 and N2O
    Did use DCD but now banned
  40. 40Differences between Phosphorous and other cyclesDoes not come from atmosphere
    No redox reactions involved
    Finite source and mined from reservoirs, mostly in liquid and solid phases
  41. 41Phosphorous cyclePool: Sediment
    Weathers from rocks and released to ecosystem via soil
    Fungi and microbes accelerate release by releasing organic acids
    P from soil taken up by plants and plants eaten by animals, returned to soil via waste and mineralised
  42. 42Contamination sources in phosphorous cycleSulfur oxidised to SO4 2-
    H2SO4 reacts with mined phosphate rock forming gypsum
    gypsum waste contains uranium and cadmium
  43. 43Transformations of POrganic and inorganic forms in soil, no redox required
    Organic is non reactive and needs to be mineralised
  44. 44AdsorptionRock weathering forms a precipitate on top of phosphorous deposit so only small amount available, added Phosphorous becomes locked in soil
  45. 45Mobility of P in soilOnly slightly soluble so immobile in soil. Plants form root hairs to reach sources of phosphorous
  46. 46Mycorrhizae and P uptakeMycelium network of mycorrhizae extends through soil to reach phosphorous soils
    Plant provides fungi sugars and fungi provides water and nutrients to plant
  47. 47Plant mycorrhizal relationship in good N and P concentrationsInhibit mycorrhizal infection at adequate nutrient concentrations, very large energy expenditure to continue infection
  48. 48Benefits of mycorrhizal infectionChanges chemical environment increasing the amount of inorganic P roots can uptake,
    Increases root surface area, increases root distance, decreases diffusion distance
  49. 49How do mycorrhizal fungi modify root environment?Direct: Produce phosphatases and organic acids
    Indirectly: Increases uptake of calcium which releases phosphorous
    Increased efficiency of NH3 use, reduces pH and increases P solubility
  50. 50EctomycorrhizaExternal mycelial sheath around roots, hartig net - nutrient exchange
  51. 51EndomycorrhizaArbuscular, most common association and effective at low phosphorous concentrations
  52. 52Difference between Sulfur and NitrogenSulfur does not need to be fixed, mostly available of sulphate
  53. 53Hierarchy of energy in sulfur compoundsH2S
    S
    SO2
    SO3 2-
    SO4 2-
  54. 54Organic sulfurHighly reduced forms are organic and in organic matter, essential for forming amino acids and proteins
  55. 55Primary source of sulfur to atmosphereDMS roduced by phytoplankton
    Has cooling effect, DMS scatters light.
    Increasing Phytoplankton to increase DMS and decrease temp investigated, but implications of increased phytoplankton unknown
  56. 56Elemental sulfurFrequently mined and found near hot springs
    Oxidised to SO42-, releases heat
    H2SO4 used to treat phosphate rock
  57. 57Phases of sulfur cycleSedimentary: Sulfur locked in organic and sedimentary deposits released through weathering and decomposition
    Gaseous: sulfur circulates globally
  58. 58Processes of sulfur cycle (4)Assimilatory reduction (Immobilisation)
    Dissimilatory reduction
    Oxidation
    Desulphurylation (Mineralisation)
  59. 59Assimilatory reductionSO42- incorporated into cells
    Sulfate reduced to sulphides (S2-) and incorporated into amino acids
  60. 60Dissimilatory reductionSo4 2- used as oxidant of sugars by anaerobic heterotrophs
  61. 61OxidationOrganisms oxidise reduced forms of sulfur to release energy
    H2S oxidised to S
    S oxidised to Sulfate
  62. 62PyriteIron and sulfure reduction forms Pyrite
    -Reduced S accumulates as pyrite
  63. 63Restoration of sulfur contaminated sitesWhen exposed to oxygen, sulfur is reduced to SO4 2- decreasing pH and inhibiting growth
    Want to keep pyrite salt in reduced form, add water to reduce oxygen contact keeping sulfur reduced. Adding CaCO3 buffers pH
  64. 64Mineralisation of SOrganic S broken down to H2S and other organic S gases
  65. 65Acid rain formationFossil fuel burned releasing SO2 into atmosphere
    SO2 forms H2SO4
    H2SO4 dissolved in and released in rain
  66. 66What is BioremediationCleaning up contaminants using microbes and plants by breaking down toxins into less harmful substances
  67. 67Types of enzymes involved in bioremediationIntra, ecto and extracellular enzymes
  68. 68Classes of enzymes involved inHydrolases, dehalogenases and oxidoreductases
  69. 69XenobioticsPollutants, have resistance to attenuation due to chemical bonds, have not been around long enough for microbes to develop pathway to remove them
  70. 70Key features of bio-remediating microbesGrows quickly in niche environment
    Modifies or consumes pollutant quickly
    Does not produce harmful byproducts
    Non pathogenic
    Aerobic preferentially due to fast metabolism
  71. 71Microbes in the Bioremediation of organic pollutantsMicrobes that degrade pesticides and hydrocarbons as their sole source of carbon and energy
  72. 72Common pollution eventsspillages or leakages of crude oil
  73. 73Optimal conditions for organic pollution degradationFavourable temperature, good nutrient supply (C:N 30:1), sufficient nutrient supply
  74. 74Anaerobic degradation of PAHs and Halogenated compoundsDechlorinate PCBs and remove halogens from aliphatic and aromatic halogen-hydrocarbons. This reaction reduces or eliminates toxicity
  75. 75Fungi and bioremediation of hydrocarbonsLigninolytic fungi can digest lignin and degrade organic pollutants
  76. 76Methanotrophs and bioremediationMethanotrophs - Aerobic bacteria use methane as carbon source and energy
    Can degrade halogenated hydrocarbons and aromatic hydrocarbons
    Use methane monooxydase
  77. 77Processes that microbes use to degrade pollutants (4)Mineralisation
    Co-metabolism
    Polymerisation
    Bioaccumulation
  78. 78MineralisationPollutant used as growth: source of energy and carbon, releases CO2
  79. 79Co-metabolismEnergy source added to transform the pollutant
  80. 80PolymerisationUses pollutant to form large polymer, less toxic and easier to degrade
  81. 81AccumulationPollutant accumulates in microbe, effective in aquatic environments
  82. 82Mechanisms of In Site remediation (4)Biostimulation
    Bioaugmentation
    Bioventing
    Biosparging
  83. 83BiostimulationStimulation of microbial activity
  84. 84BioaugmentationInoculating soil with microbes
  85. 85BioventingInjecting air into unsaturated zones - provides oxygen to existing microbes
  86. 86BiospargingUsing existing microbes to degrade pollutants in saturated zones. Injecting air and nutrients into saturated and unsaturated zones
  87. 87Ex situ bioremediation pathways (3)Land farming
    Turned Windrows
    Forced vented piles
  88. 88Land farmingContaminated soil excavated and spread out in thin layer over lined surface. Remediation enhanced by regular turning and addition of nutrients. Requires large area, but simple and cheap
  89. 89Turned WindrowsContaminated soil excavated and shaped into piles on a lined surface
    Pile periodically aerated
    Cheap and effective
  90. 90Forced vented pilesShaped into piles 3m high -6m wide
    Air injected or vacuum
    Vapours collected and treated by activated carbon to reduce emissions
  91. 91Selenium decontaminationAdding contaminated soil to bioreactor, producing selenium metalloids, and other useful byproducts
  92. 92PhytoremediationUsing plants
    Roots can absorb pollutants and heavy metals and break them down and prevent harmful substances from reaching waterways

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196.213 Flashcards on Ecology unit 5, created by Kelly Chamberlain on 19/05/2019.
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