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M IKROORGANISME DALAM SIKLUS BIOGEOKIMIA Oleh: Dr. Ratu Safitri, MS Laboratorium Mikrobiologi. Jurusan Biologi F-MIPA Universitas Padjadjaran.

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Presentasi berjudul: "M IKROORGANISME DALAM SIKLUS BIOGEOKIMIA Oleh: Dr. Ratu Safitri, MS Laboratorium Mikrobiologi. Jurusan Biologi F-MIPA Universitas Padjadjaran."— Transcript presentasi:

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2 M IKROORGANISME DALAM SIKLUS BIOGEOKIMIA Oleh: Dr. Ratu Safitri, MS Laboratorium Mikrobiologi. Jurusan Biologi F-MIPA Universitas Padjadjaran

3 L INGKUP M ATERI : Ikhtisar Siklus Biogeokimia : - Siklus N dan Reaksi dalam siklus - Siklus O - Siklus P - Siklus C 2

4 D ASAR DARI KONSEP SIKLUS BIOGEOKIMIA Semua materi siklus tidak diciptakan atau dihancurkan Sehubungan karena bumi adalah suatu sistem tertutup, maka semua hal yang berada di dalamya akan dalam suatu siklus. Siklus Biogeokimia: perbahan atau sklus materi dalam suatu sistem lingkungan. 3

5 J ENIS MATERI YANG BEREDAR  Element kimia (carbon, nitrogen, oxygen, sulfur, Phosphor) atau molekule air.  Makronutient : diperlukan pertukaran dalam jumlah yang besar, misal : potassium, calcium, iron, magnesium  Mikronutrien beredar dalam jumlah yang sangat kecil, misalnya: boron (tanaman hijau) copper (untuk aktifitas ensim) molybdenum (nitrogen-fixing bacteria) 4

6 E ARTH ’ S ECOSYSTEMS ARE MAINTAINED BY A CONSTANT INFLUX OF ENERGY Solar Energy Autotroph Herbivore Carnivore Respiratory Loss Transformation Loss of Energy 5

7 B IOGEOCHEMICAL C YCLES Cycling of chemical elements between living and non- living portions of the earth’s ecosystems Biotic Abiotic Uptake Decomposition Respiration Excretion

8 B IOGEOCHEMICAL C YCLE : Siklus utama yang akan dibahas: Siklus nitrogen Siklus oxygen Siklus phosphorus Siklus carbon Sirkulasi molekul kimia dalam siklus biogeokimia dan interaksinya dalam siklus adlah sangat penting untuk memelihara ekosistem terestrial, air tawar, dan ekosistem laut. Perubahan iklim global, temperatur, hujan, dann kestabilan ekosistem sangat tergantung pada siklus biogeokimia. 7

9 Siklus N 8

10 N ITROGEN BEREDAR DI T ANAH -Komposisi N udara: 80% - Nitrogen beredar dalam peredaran : (a). Bakteri dalam tanah akan merubah nitrat menjadi gas ke udara (denitrifikasi) (b) Dengan adanya cahaya, sejumlah nitrogen dioksidasi dan bergabung dengan air membentuk asam dan akan jatuh dalam bentuk hujan. Tanaman akan mengambil nitrat dan mengubahnya menjadi bahan protein yang akan diantarkan oleh karnivora dan herbivora dalam rantai makanan. Ketika organisma mengelurakan limbah, nitrogen akan dikembalikan ke lingkunga. Ketika biota mati, akan didekomposisi dan dikonversikan menajdi amoniak. 9

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13 Surface water Oxidized layer Reduced soil layer [NH 4 ] HIGH Low [NH 4 ] Slow Diffusion Biodegradation C/N <20 C/N >20 12

14 Surface water Oxidized layer Reduced soil layer [NH 4 ] HIGH Low [NH 4 ] Slow Diffusion nitrification [NO 3 ] high 13

15 Surface water Oxidized layer Reduced soil layer [NO 3 ] high Leaching [NO 3 ] Low N2N2 Denitrification 14

16 Nitrogen Fixation Nodules on plant roots 15

17 R EAKSI - REAKSI DALAM S IKLUS N ITROGEN

18 S UMBER N Lightning Inorganic fertilizers Nitrogen Fixation Animal Residues Crop residues Organic fertilizers 17

19 F ORMS OF N ITROGEN Urea  CO(NH 2 ) 2 Ammonia  NH 3 (gaseous) Ammonium  NH 4 Nitrate  NO 3 Nitrite  NO 2 Atmospheric Dinitrogen  N 2 Organic N R OLES OF N ITROGEN Plants and bacteria use nitrogen in the form of NH 4 + or NO 3 - It serves as an electron acceptor in anaerobic environment Nitrogen is often the most limiting nutrient in soil and water. 18

20 G LOBAL N ITROGEN R ESERVOIRS Nitrogen Reservoir Metric tons nitrogen Actively cycled Atmosphere3.9*10 15 No Ocean  soluble salts Biomass 6.9* *10 8 Yes Land  organic matter  Biota 1.1* *10 10 Slow Yes 19

21 N ITROGEN IS A KEY ELEMENT FOR amino acids nucleic acids (purine, pyrimidine) cell wall components of bacteria (NAM). 20

22 N ITROGEN C YCLES Ammonification/mineralization Immobilization Nitrogen Fixation Nitrification Denitrification 21

23 R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N2ON2O N2N2 22

24 A MMONIFICATION OR M INERALIZATION R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N2ON2O N2N2 23

25 M INERALIZATION OR A MMONIFICATION Decomposers: earthworms, termites, slugs, snails, bacteria, and fungi Uses extracellular enzymes  initiate degradation of plant polymers Microorganisms uses: Proteases, lysozymes, nucleases to degrade nitrogen containing molecules Plants die or bacterial cells lyse  release of organic nitrogen Organic nitrogen is converted to inorganic nitrogen (NH 3 ) When pH<7.5, converted rapidly to NH 4 Example: Urea NH CO 2 24

26 I MMOBILIZATION The opposite of mineralization Happens when nitrogen is limiting in the environment Nitrogen limitation is governed by C/N ratio C/N typical for soil microbial biomass is 20 C/N < 20  Mineralization C/N > 20  Immobilization 25

27 N ITROGEN F IXATION Energy intensive process : N 2 + 8H+ + 8e ATP = 2NH 3 + H ADP + 16 Pi Performed only by selected bacteria and actinomycetes Performed in nitrogen fixing crops (ex: soybeans) R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N2ON2O N2N2 26

28 M ICROORGANISMS FIXING Azobacter Beijerinckia Azospirillum Clostridium Cyanobacteria Require the enzyme nitrogenase Inhibited by oxygen Inhibited by ammonia (end product) Anabaena Microcystis 27

29 R ATES OF N ITROGEN F IXATION N 2 fixing systemNitrogen Fixation (kg N/hect/year) Rhizobium-legume Cyanobacteria- moss30-40 Rhizosphere associations 2-25 Free- living1-2 28

30 B ACTERIAL F IXATION Occurs mostly in salt marshes Is absent from low pH peat of northern bogs Cyanobacteria found in waterlogged soils 29

31 N ITRIFICATION Two step reactions that occur together : 1 rst step catalyzed by Nitrosomonas 2 NH O 2  2 NO H 2 O+ 4 H + 2 nd step catalyzed by Nitrobacter 2 NO O 2  2 NO 3 - Optimal pH is between If pH < 6.0  rate is slowed If pH < 4.5  reaction is inhibited R- NH 2 NH4NH4 NO 2 NO 3 NO 2 NONO N2ON2O N2N2 30

32 D ENITRIFIKASI Removes a limiting nutrient from the environment 4NO C 6 H 12 O 6  2N H 2 0 Inhibited by O 2 Not inhibited by ammonia Microbial reaction Nitrate is the terminal electron acceptor R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N2ON2O N2N2 31

33 Interactive Nitrogen Cycle N 2 Fixation Plant and Animal Residues Industria l Process es Fertilizer Lightning, Rainfall Atmosphe re Organic Matter Volatilizati on Leachin g N 2, N 2 O, NO R-NH 2 + Energy + CO 2 R-NH 2 + H 2 O R-OH + Energy + 2NH 3 Soil exchange sites 2NH OH - 2NO H 2 O + 4H + 2NH OH - NO 3 - Pool Plant/Micro bial Sink Pla nt Los s Back to Intro Page 32

34 ORGANIC MATTER MESQUITE RHIZOBIUM ALFALFA SOYBEAN BLUE-GREEN ALGAE AZOTOBACTER CLOSTRIDIUM PLANT AND ANIMAL RESIDUES R-NH 2 + ENERGY + CO 2 R-NH 2 + H 2 O R-OH + ENERGY + 2NH 3 MATERIALS WITH N CONTENT < 1.5% (WHEAT STRAW) MATERIALS WITH N CONTENT > 1.5% (COW MANURE) MICROBIAL DECOMPOSITION HETEROTROPHIC AMINIZATION BACTERIA (pH>6.0) FUNGI (pH<6.0) AMMONIFICATION GLOBAL WARMING pH>7.0 2NH OH - FIXED ON EXCHANGE SITES +O 2 Nitrosomonas 2NO H 2 O + 4H + IMMOBILIZATION NH 3 AMMONIA-3 NH 4 + AMMONIUM-3 N 2 DIATOMIC N0 N 2 O NITROUS OXIDE1 NO NITRIC OXIDE2 NO 2 - NITRITE3 NO 3 - NITRATE5 OXIDATION STATES ATMOSPHERE N 2 O NO N 2 N2O2-N2O2- NH 3 SYMBIOTICNON-SYMBIOTIC + O 2 Nitrobacter FERTILIZATION LIGHTNING, RAINFALL N2 FIXATION DENITRIFICATION PLANT LOSS AMINO ACIDS NO 3 - POOL LEACHING AMMONIA VOLATILIZATION NITRIFICATION NH 2 OH Pseudomonas, Bacillus, Thiobacillus Denitrificans, and T. thioparus MINERALIZATION + NITRIFICATION IMMOBILIZATION NO 2 - MICROBIAL/PLANT SINK TEMP 50°F pH 7.0 LEACHING DENITRIFICATION LEACHING VOLATILIZATION NITRIFICATION ADDITIONS LOSSES OXIDATION REACTIONS REDUCTION REACTIONS HABER BOSCH 3H 2 + N 2 2NH 3 (1200°C, 500 atm) Joanne LaRuffaRobert Mullen Wade ThomasonSusan Mullins Shannon Taylor Heather Lees Department of Plant and Soil Sciences Oklahoma State University INDUSTRIAL FIXATION Back to Intro Page 33

35 S IKLUS O KSIGEN 34

36 Tanaman menggunakan energi matahari untuk mengkonversikan karbondioksida dan air menjadi karbohidrat dan oksigen melalui fotositesis. 6CO2 + 6H2O + energy → C6H12O6 + 6O2 Organisma fotosintetik berperan dalam siklus oksigen termasuk tanaman, phytoplankton di laut. Biota laut cyanobacteria Prochlorococcus ditemukan tahun 1986.cyanobacteriaProchlorococcus Hwan membentuk setengah siklus dari oksigen yang digunakan untuk memecah karbohidrat menjadi energi dalam proses respirasi. O2 + carbohydrates → CO2 + H2O + energy 35

37 S IKLUS P 36

38 S IKLUS P DI L AUTAN 37

39 S IKLUS P DI DALAM T ANAH 38

40 The phosphorus cycle describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere. The atmosphere does not play a significant role, because phosphorus and phosphorus-based compounds are usually solids at the typical ranges of temperature and pressure found on Earth. phosphorus Phosphorus normally occurs in nature as part of a phosphate ion, consisting of a phosphorus atom and some number of oxygen atoms, the most abundant form (called orthophosphate ) having four oxygens: PO43-. Most phosphates are found as salts in ocean sediments or in rocks. Over time, geologic processes can bring ocean sediments to land, and weathering will carry terrestrial phosphates back to the ocean. sedimentsweathering 39

41 Plants absorb phosphates from the soil and phosphate enters the food chain. After death, the animal or plant decays, and the phosphates are returned to the soil. Runoff may carry them back to the ocean or they may be reincorporated into rock. The primary biological importance of phosphates is as a component of nucleotides, which serve as energy storage within cells (ATP) or when linked together, form the nucleic acids DNA and RNA. Phosphorus is also found in bones, and in phospholipids (found in all biological membranes).nucleotidesATPDNARNAphospholipids Phosphates move quickly through plants and animals; however, the processes that move them through the soil or ocean are very slow, making the phosphorus cycle overall one of the slowest biogeochemical cycles. 40

42 Siklus Karbon 41

43 Usually thought of as four major reservoirs of carbon (the atmosphere, the terrestrial biosphere - which includes freshwater systems and non-living organic material, such as soil carbon -, the oceans with dissolved inorganic carbon and living and non-living marine biota, and the sediments which includes fossil fuels) interconnected by pathways of exchange. dissolved inorganic carbonsedimentsfossil fuels The exchanges between reservoirs, occur because of various chemical, physical, geological, and biological processes. The ocean contains the largest active pool of carbon near the surface of the Earth, but the deep ocean part of this pool does not rapidly exchange with the atmosphere.deep ocean 42

44 The global carbon budget is the balance of the exchanges (incomes and losses) of carbon between the carbon reservoirs or between one specific loop (e.g., atmosphere - biosphere) of the carbon cycle. IN THE OCEAN: The seas contain around gigatonnes of carbon, mostly in the form of bicarbonate ion. Inorganic carbon, that is carbon compounds with no carbon- carbon or carbon-hydrogen bonds, is important in its reactions within water. This carbon exchange becomes important in controlling pH in the ocean and can also vary as a source or sink for carbon.pH 43

45 Carbon is readily exchanged between the atmosphere and ocean. In regions of oceanic upwelling, carbon is released to the atmosphere. Conversely, regions of downwelling transfer carbon (CO2) from the atmosphere to the ocean. When CO2 enters the ocean, carbonic acid is formed: CO2 + H2O ⇌ H2CO3 This reaction has a forward and reverse rate, that is it achieves a chemical equilibrium. Another reaction important in controlling oceanic pH levels is the release of hydrogen ions and bicarbonate. This reaction controls large changes in pH:chemical equilibrium H2CO3 ⇌ H+ + HCO3− 44


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