Microbes and The Environment Topic F2, F5 Below: soil bacteria

Ecological Roles of Microbes Producers Decomposers Nitrogen Fixers

Nitrogen (be able to draw)

Nitrogen Cycle Atmospheric Nitrogen Gas (N2) Roles of Bacteria Nitrogen Fixation Nitrogen Gas  Ammonium ions Decomposition and Ammonification Dead stuff  Ammonium ions Nitrification Ammonium  Nitrates Assimilation Nitrates being used by plants to make proteins and other molecules needed by living things Denitrification Nitrates Nitrogen Gas

Outline the roles of Rhizobium, Azobacter, Nitrosomonous, Nitrobacter and Pseudomonas denitrificans in the nitrogen cycle. Rhizobium and Azobacter--nitrogen fixing Nitrosomonous oxidizes ammonia to form nitrite. Nitrobacter oxidizes nitrite to form nitrate. (nitrification) Pseudomonas denitrificans denitrify

Describe the conditions that favor dentrification and nitrification. Denitrification-- decreases soil fertility and plant growth. water-logged soils. poor aeration and deficiency of oxygen in the soil. Nitrification ploughed soil because then the oxygen gets into the soil and makes it unfavorable for dentrifying bacteria. This is why soil is aerated

Sewage and Bacteria Outline the consequences of releasing raw sewage and nitrate fertiliser into rivers. Include: pathogens Eutrophication algal blooms deoxygenation increase in biochemical oxygen demand (BOD)

The role of saprotrophic bacteria in the treatment of sewage: Trickling filter beds- consists of a fixed bed of rocks, gravel, wood or plastic media over which sewage flows downward and causes a layer or film of microbial slime to grow. This slime has saprotrophic bacteria that decompose the sewage Reed Bed System- Self contained, artificially engineered, wetland ecosystem for treatment and recycling of sewage. Saprotrophic bacteria decompose…

Reed bed system

Bioremediation Bioremediation -- any process that uses living things or their enzymes to return the natural environment to its original condition after being altered by contaminants Bioremediation of soil by bacteria… Selenium Solvents Pesticides Bioremediation of contaminated water by bacteria Oil spills Other contaminants Big picture: Certain bacteria can be used to decompose and/or convert contaminants into less toxic substances.

Metabolism of Microbes Photoautotroph: An organism that uses light energy to generate ATP and produce organic compounds from inorganic substances. (ex. Cyanobacteria, algae etc.) Photoheterotroph: an organism that uses light energy to generate ATP and obtains organic compounds from other organisms. (ex. Purple and green non-sulfur bacteria) Chemoautotroph: an organism that uses energy from chemical reactions to generate ATP and produce organic compounds from inorganic substances. (ex. Deep sea vent bacteria) Chemoheterotroph: an organism that uses energy from chemical reactions to generate ATP and obtain organic compounds from other organisms. (ex. Pathogenic bacteria)

Compare photoautotrophs with photoheterotrophs Energy source: for both = light Carbon source: Photosynthesis for photoautotrophs Food (organic compounds) for photoheterotrophs.

Compare chemoautotrophs and chemoheterotrophs Energy source Chemoautotrophs use chemical reactions of inorganic compunds to produce ATP Chemoheterotrophs use organic compounds for energy (respiration) Carbon source Chemoautotrophs – use inorganic sources of carbon to make organic substances Chemoheterotrophs – get organic compounds directly from food.

Draw and label: filamentous cyanobacterium (Anabaena) This image is copyright Dennis Kunkel at www.DennisKunkel.com Draw and label: filamentous cyanobacterium (Anabaena) An example photoautotroph. Photosynthetic cell– does photosynthesis! Heterocyst—cell that does nitrogen fixation

Biomass can be used as a source of fuels such as methane and ethanol. Explain the principles involved in the generation of methane from biomass… Anaerobic conditions (sealed) 3 types of bacteria involved Type 1: decompose organic material to organic acids and alcohol. Type 2: Convert organic acids and alcohol into carbon dioxide, hydrogen, and acetate Type 3: Methanogenic bacteria/archaea such as methanobacillus and methanococcus Produce methane from CO2,, acetate and Hydrogen. The methane is then burnt as a source of energy. The rest of thedigested material is rich in nutrients and used as fertiliser.